VAG 405 SCAN TOOL

VAG405 SCAN TOOL

A week ago I  ordered a VAG405 scan tool from an online store. This scan tool is essentially a dedicated stand-alone OEM level diagnostic device for scanning Volkswagen, Audi, Skoda, Seat, VW Golf, VW GTI , VW Polo, VW Jetta, VW Beetle, VW Passat, VW Touareg, vehicles... etc. Restated, it's a scan tool specific to VAG vehicles manufactured since 1990 to the current day, yet it is quite unlike the Autel D900 diagnostic scan tool I evaluated in a previous blog which is not VAG specific but can scan several makes of vehicles.

As can be seen, it can scan Golf 3, Golf 4 Beetle, New Beetle, Passat.....

It also scans the Polo, Sharan, Lupo, Bora and the Transporter, etc...

However, when the scan tool arrived, I expected something much smaller, like perhaps the size of a Samsung S7, but to my surprise it was actually quite substantial, sporting a large easy to read backlit LCD with OBD/EOBD functionality. The box also included a nylon carry case, an OBD2 cable, a USB cable and a VAG405 user's manual.

Initially, I was intrigued by the general claims made by the advert and reiterated on  the actual box it which it was packaged. It stated that  the VAG405 scan tool reads most electronic controlled modules and erases Diagnostic Trouble Codes (DTCs) from the ECU's non-volatile memory triggered by the Engine, Transmission, ABS, Airbags, Climatic control (AC), Steering wheel, Immobilizer, Instrument cluster and Central electronics, etc. That it reads and clears generic trouble codes on VAG vehicles using either ISO 9141-2 ("CARB"), or ISO 1430 ("KWP-2000") and ISO-15765 ("CAN") protocols for the latest cars and can even resets the MIL light, airbag, ABS and a host of other  OBDII systems.

ISO 1941 Protocol

KWP2000 Protocol

CAN Bus Protocol

And that it can also resets oil service light and retrieve the ECU embedded VIN (Vehicle Information Number) as well as display I/M readiness. 

All of this just sounded too good to be true so I just had to get one. But after running tests I am sorry to say that I am not too impressed with it. Not because it is brick but that it is rather inclined towards cars built prior to y2k.  I found that the VAG405 timed-out and froze when scanning for trouble codes, while displaying "Please Wait" on its LCD screen. In order to reset it, I had to physically unplug the 16 pin DLC then reconnect, else I was going to wait forever.  I assume the "Please Wait" (timeout) is an incompatibility between the non-volitile memory used in my 2007 VW Polo 2.0L Highline and that used in VW prior to y2k. However, most of the other functions appear to be compatible.

I like the fact that it is powered from the car's battery via the DLC and therefore doesn't need batteries but a nice to have would have at least been an on-off switch fitted to the scan tool, to reset the scan tool when it freezes. The software is fairly simplistic and easy to use, though rather limited since it doesn't allow you to change module coding. I couldn't retrieve my car's embedded VIN and I don't think this VAG405 can't retrieve it from  any later model VAG vehicle. It is a very nifty scan tool and great value for money if you own an older VW vehicle or Audi but steer clear of it if your car is newer that year 2000. Perhaps this peculiarity is specific to my scan tool yet everything else seem to function as per claim in the advert and on the box.

Below is a series of photographs that I uploaded to demonstrate the functionality of this scan tool.

Engine control Module data

ABS control Module data

Airbag control Module data

Instrument Control Module data

Electronics Module Control data

Gateway Control Module data

Comfort Control Module data

Failed communication occurred several times but after unplugging DLC and
reinserting comms appeared to be much better.

The software is quite informative, guiding you to causes of comms errors.

Link Error! This happened when I scanned the Steering Control Module and the Radio Control Module, both of which was present and responded to the Autel D900 scan tool.

OBD readiness tests of the 8 monitors, 6 of which are feature in the above image and
2 are featured in the image below, all of which pass,

The first 6 Control Modules, A peculiarity I picked up is that the Airbags is listed before ABS which
isn't normal compared to other dedicated scan tools and computerized scan tool software.

Control Modules 16 -25 

Control modules 35 -56

I don't believe that there are no stored codes because I know there are airbag error codes stores which I determined using VCDS. Like I mentioned earlier, the VAG405 is more suited to vehicles manufactured prior to y2k.

VOLKSWAGEN'S EXISTENCE THREATENING CRISES

Volkswagen's Knock-on / Snowball effect

During September of 2015 Volkswagen AG admitted that they created sophisticated software that could  determined when the cars in which it was installed were tested by the U.S. Environmental Protection Agency (EPA) thus able to turn on the pollution controls but once all wheels were in rotation and the steering wheel was turned, the cheat software turned off. The cars implicated in Volkswagen's emissions scandal include the VW Jetta TDI, the VW Beetle, VW Golf  Model 2009-2015 TDI's, the Audi A3 and the Passat 2014- 015 model .  

Apparently Volkswagen cheated at emissions tests for seven years before being caught by the International Council on Clean Transportation. With the result that all sales of affected VW cars were stopped. In a the inquests that followed Volkswagen was found guilty and liable to compensate all the car owners who were cheated.

The owners of the 482,000 Volkswagen 2-liter diesel vehicles implicated in the company's emissions scandal  could each get as much as $7,000 because the automaker is willing to shell out over $10 billion in a civil settlement to U.S. car owners, in order to make things right. The automaker is expected to award each of these  car owners between $1,000 and $7,000 and will attempt to repair as many of the automobiles as it can, at no cost to the consumers. 

European are also shouting compensation and Europe's Industry Commissioner Elzbieta Bienkowska  says it would be biased and very unfair of  Volkswagen to treat European customers  differently  because of different legal system, and that Volkswagen (VOW) should monetarily   compensate European customers same compensation as US drivers. And she added "Treating consumers in Europe differently than U.S. consumers is no way to win back trust,"  However  VW officials in Europe said that they will repair vehicles and remove illegal software, but have no intention to pay consumers compensation, arguing they suffered no loss.

As Volkswagen prepares to spend $10.2 billion to buy back vehicles in the U.S. a South Korean Volkswagen executive has been arrested after a warrant was issued by the Seoul District Court for charges related to Volkswagen's emissions cheating. Claiming the executive should have submitted test results for new cars but tried to fool the system by submitting test results for previous models. In what could mean even more trouble for  Volkswagen, the VW executive told prosecutors he altered the software for the electronic control units based on direct orders from Volkswagen management. Volkswagen Korea is facing class-action lawsuits from Korean owners who are demanding compensation similar to what has been offered to owners in the U.S. 

From this it is clear that the Snowball effect will soon go global and evey country will jump on the band wagon in order to get a piece of Volkswagen. The million dollar question is, " Will Volkswagen survive a 80 billion USD "existence -threatening  crises.

WHAT IS A VW EPC WARNING LIGHT

What Is a VW EPC Warning Light

The EPC warning light is an instrument cluster based LED found on all Volkswagen, Audi, Seat and Skoda vehicles fitted with a drive-by-wire system and EPC stands for Electronic Power Control. However the EPC warning light is not exclusive to these VAG cars, most other motor manufacturers also have them, since it's legislated to be part of the OBDII system. This EPC light when lit displays the letters EPC and primarily warns the driver that there is problems in the engine's torque system - (acceleration system). The reason why the EPC turns on, problem could be many, among which are the vehicle's knock sensors, its throttle system, its cruise control, its mass air flow system, its engine speed verification system or any of the other associated systems that cooperate in the drive-by-wire schema. 

When this EPC light comes on, the vehicle’s throttle valve (butterfly) may be limited in order to protect the engine from damage. It prevents the engine from revving above 2000rpm. This is known as limp mode and the ECU permits just sufficient power to drive the vehicle to a service center for repairs. To remedy the problem, the vehicle’s ECU should be scanned with an automotive diagnostic too, in order to extract the DTC's related to the torque problem.  Cars with an accelerator cable are also fitted with an EPC light but the ECU software is quite different, yet the overall principal remains the same.

All Volkswagen (VAG) vehicles have a whole array of dashboard warning lights in their instrument panels, specifically designed to alert the driver to any vehicle malfunctions or problems. In fact so does all most modern day automobiles. Having said that, it is only a matter of time before these lights start lighting up. Invariably and inevitably all cars will breakdown at sometime or the other but its nice to be warned about a mechanical problem before it actually occurs. For example, having a low coolant level light or an low engine oil-level light flash at you, accompanied by an audio alert is a blessing because complete loss of either coolant or engine oil could result in a very expensive repair. 

The one warning light that puzzles most drivers is the VW EPC warning light. Driver often ask, what is the VW EPC warning light? Like I've mentioned above, it is a bright yellow dashboard light with the letters EPC inscribed in bold.it  When lights-up to draws your attaention to a potential malfunction in the EPC system. When it lights up whilst driving and the trouble is related to a safety issue, the car will more than likely go into limp mode. This may sound quite serious but in most cases it's not. There are several reasons why EPC Dashboard Warning Light turns on, but through a process of elimination the cause can be tracked down fairly easily. 

The Engine Speed Sensor is  known to cause the EPC light to turn on. The engine speed sensor is a proximity magnetic transducer counting the revolutions of the flywheel / crankshaft and sends a steady stream of pulses to the ECU. So when this stream of data is interrupted for whatsoever reason for only a fraction of a second, the ECU  detects this and turns on the EPC light and cuts power to the engine. It does this to protect the engine from damage. 

If you have a scan tool, check for DTC errors. The following error code, 17745 /P1337, 17746 / P1338, 17747 / P1339 and 17748 / P1340 are the troubles codes that provides a  tell tail sign that the engine speed sensor is either loose or faulty, hence the car's engine cuts-out whilst driving and the speedometer is inoperative.  But in some cases the engine will start again. When this symptoms repeats itself often, you should know it is time to replace that pesky engine speed sensor.

The Accelerator Pedal itself is often the main culprit that causes EPC problems. A telltale sign is that the engine idles a lot faster than it aught to. To verify this, physical pull the accelerator pedal away from the floor board while the car is idling. If it reduces the engine's revs back to normal, then it is time to replace it, because the potentiometers that's built into the the accelerator pedal, have gone faulty. Accelerator pedal problems are numerous and the following DTC, 16504 / P0120, 16505 / P0121, 16506 / P0122, 16507 / P0123, 18038 / P1630, 18039 / P1631, 18040 / P1632, 18041 / P1633, 18042 / P1634, are linked to accelerator pedal errors. 

Mass air flow sensor is another engine component that can cause the EPC light to turn on. Cleaning the  mass air flow sensor with compressed air does often solve the problem but if the issue persists, its time to replace mass air flow sensor. But before changing it, check to see if any of the rubber hoses in its vicinity isn't perished. An leak in Air Intake System wil allowing air unmonitored to enter the intake which will throw a P2279 / 15093 error or a P0068 / 15101 error.


The Throttle body is by far the most common cause of an EPC problem though in many cases it is not the throttle body that's at fault but rather that it the needs to be recalibrated (adaptation). The scan codes like P2135 / P2136 / P2137 / P2138 / P2139  and P2140, will give a  good idea as to whether or not the throttle body require replacement.  But in many cases it turns out to be  wiring harness issue. The plugs that connects the throttle drive motor and the throttle position sensors is fairly troublesome ad should be checked before throttle is replace.

The Brake light switch can also cause the EPC light to come on because the torque control circuit uses the brake light signal as a ECU input signal when the car decelerates.  

The Injectors and the Ignition Coils can also cause the EPC light to turn on. I've heard that an incorrect spark gap on the plugs can also cause an EPC problem but haven't experienced it yet.  Driving with very little gasoline in the tank can also cause the EPC light to turn on because the high pressure fuel pump may lose pressure which then notifies the ECU to inhibit the torque circuit and switch on the EPC light and make the car go into limp mode.

I've experienced the Knock Sensor turn on the EPC light. Spirited driving also turns on the EPC light.

So as you can see there are several things that can cause an EPC fault.  This is not a complete list of EPC problems but as new ones are identified, I will post them.  The following questions prompted me to write a synopsis of what an EPC light is!

___________________________________________________

What is an EPC light? What is an EPC warning light? What is an EPC light on Volkswagen? What Is the VW EPC Warning Light? What is the EPC light on a Volkswagen Jetta? What is EPC on a Volkswagen? What does it mean if the EPC warning light comes on in a Volkswagen? Volkswagen - EPC Warning Light, What does an EPC light on the dash of a Polo match car mean? EPC light came on and lost all power. 

The EPC warning symbol came on today while driving. EPC Light and stalling. EPC light came on and can't start the engine. EPC light on, what does it mean ? EPC light and engine check light. EPC warning light. Epc light. EPC + power loss/no boost.  Do not exceed 4000 rpm  EPC light.   EPC error where the car shakes terribly.  ESP EPC & Engine Light ON.  EPC Light and Stalling. Polo bluemotion 58 plate and a yellow engine light came on. I read the manual but still not sure something to do with the exhaust??

A little help as my wife needs the car for work.2002 1.6L GOLF, EPC light on. POWER LOSS An EPC light will appear on the dash randomly whilst driving. Once it is on, there is a noticeable loss in power and it stays this way until the... volkswagon polo epc warning.step by step guide to turn light off please, preferably without visiting expensive vw garage. Have diagnostic computer to see code! EPC light came on and engine will not rev higher. I have a vw polo and the EPC warning light has come on what should i do? Orange light 03 vw polo. VW Polo Map sensor fault code idling poorly. EPC light on my dashboard 2001 vw polo. It has something to do with the engine management, retarding the power of the engine.

AUTEL D900 CONTINUED

AUTEL 900

This blog is a continuation of a previous blog named AUTEL D900 SCAN TOOL in which I outlined its indispensability and necessary tool to repair any VAG vehicle. Anyway, I hooked up the D900 2015 version to my polo classic 2.0l highline. As can be seen below, its software is already at version 15.7 and dated July 2015 meaning that it's a huge improvement compared to the 2011 model. There are 30 vehicle manufacturers  listed in the Autel 900 menu, the 28th of which is Volkswagen and the last selection is other, meaning any vehicle not listed. I did a DTC scan but there was none stored in memory. Neither was there any vehicle information nor freeze frame data. Compared to VCDS the live data is accurate. I was interested to see the coolant temperature increase while the car idled and that's exactly what I saw. 

The OBD2 monitors are abbreviated and I dropped in a list for ease of identification below. Unfortunately I can't demonstrate the DTC feature since there were not DTCs to display. I verified with my VCDS to make sure that the D900 isn't saying that there isn't any while there may be some.

Abreviations o the various OBD2 monitors.

In my opinion the D900 is good value for money. Initially  I was sceptical that it didn't support Polo but it clearly does. It supports Audi and Porsche but doesn't specifically list Skoda nor Seat.  It may read then under other but I will have to check this and this post later. A list of VAG cars that it supports can be seen here.

The D900 laying on the passenger seat.

The D900 switch on, first screen.

D900 supports Volkswagen and Audi 

D900 has 7 functions, 6 of which can be seen here

D900 reads MIL status, Freeze frame and I/M readiness

Live data from my VW polo 

More live date from my VW Polo

The following 3 pics are  self explanatory

More live data from my VW Polo

AUTEL 900 works on the following list of VW Polo Highline Cars

vw polo highline
swift zdi vs vw polo highline
volkswagen polo 1.2 l highline
volkswagen polo 1.2 l highline d
volkswagen polo 1.2 mpi highline
volkswagen polo 1.2 tsi highline
volkswagen polo highline 1 4
volkswagen polo 1.4 5p. highline
volkswagen polo 1.4 highline 75cv
volkswagen polo 1.4 highline 80cv
volkswagen polo 1.4 tdi highline 75cv
volkswagen polo 1.4 tdi highline 80cv
volkswagen polo 1.6 l highline
volkswagen polo 1.9 tdi highline 96kw for sale
volkswagen polo 6n2 highline
volkswagen polo classic 1.6 highline
volkswagen polo highline accessories
volkswagen polo highline audio system
volkswagen polo highline ausstattung
volkswagen polo highline black
volkswagen polo highline blue
volkswagen polo highline bluetooth
volkswagen polo highline colours
volkswagen polo highline deep black
volkswagen polo highline diesel mileage
volkswagen polo highline diesel on road price
volkswagen polo highline diesel on road price bangalore
volkswagen polo highline diesel on road price in chennai
volkswagen polo highline diesel on road price in hyderabad
volkswagen polo highline diesel price in india
volkswagen polo highline diesel review
volkswagen polo highline diesel second hand
volkswagen polo highline diesel used
volkswagen polo highline diesel used cars
volkswagen polo highline images
volkswagen polo highline india
volkswagen polo highline india review
volkswagen polo highline interior photos
volkswagen polo highline interiors
volkswagen polo highline km 0
volkswagen polo highline mexico
volkswagen polo highline mileage
volkswagen polo highline model
volkswagen polo highline occasion
volkswagen polo highline on road price
volkswagen polo highline petrol features
volkswagen polo highline petrol mileage
volkswagen polo highline petrol on road price bangalore
volkswagen polo highline petrol user reviews
volkswagen polo highline price bangalore
volkswagen polo highline price in chennai
volkswagen polo highline price in mumbai
volkswagen polo highline r line
volkswagen polo highline red
volkswagen polo highline review
volkswagen polo highline review team bhp
volkswagen polo highline specifications
volkswagen polo highline specs
volkswagen polo highline sr
volkswagen polo highline tdi
volkswagen polo highline tyre size
volkswagen polo highline vs gt
volkswagen polo highline vs hyundai i20 asta
volkswagen polo highline vs swift zxi
volkswagen polo highline white
volkswagen polo india highline price
volkswagen polo reviews highline petrol
vw polo 1 2 tsi 105 highline 5d
vw polo 1 6 tdi 105 highline 5d
vw polo 1 6 tdi 90 highline bm 5d
vw polo 1 6 tdi highline
vw polo 1.2 cr highline bsiv
vw polo 1.2 cr highline bsiv price
vw polo 1.2 highline 64ps
vw polo 1.2 highline review
vw polo 1.2 tsi dsg highline
vw polo 1.2 tsi dsg highline optimum
vw polo 1.2 tsi highline eu
vw polo 1.2 tsi highline forum
vw polo 1.2 tsi highline jahreswagen
vw polo 1.2 tsi highline kopen
vw polo 1.2 tsi highline pepper grey
vw polo 1.2 tsi highline r-line
vw polo 1.4 fsi highline
vw polo 1.4 highline
vw polo 1.4 highline gebraucht
vw polo 1.4 highline nasıl
vw polo 1.6 tdi highline gebraucht
vw polo 1.6 tdi highline km 0
vw polo 1.9 tdi highline
vw polo 1.9 tdi highline 74kw
vw polo 1.9 tdi highline 96kw
vw polo 1.9 tdi highline 96kw for sale
vw polo 1.9 tdi highline for sale
vw polo 2.0 highline for sale
vw polo 2.0 highline fuel consumption
vw polo 2.0 highline review
vw polo 2.0 highline specs
vw polo 5 highline
vw polo 50 servo highline
vw polo 60 servo highline
vw polo 6c highline
vw polo 6n highline
vw polo 6n2 highline ausstattung
vw polo 6r highline
vw polo 6r highline ausstattung
vw polo 6r highline test
vw polo 81 kw highline
vw polo 9n highline
vw polo 9n highline ausstattung
vw polo 9n3 highline
vw polo classic 2.0 highline
vw polo classic 2.0 highline for sale
vw polo gp 1.2 tsi highline
vw polo highline
vw polo highline 1 2 tsi
vw polo highline 1 4 tdi
vw polo highline 1.2 tsi
vw polo highline 1.2 tsi 2014
vw polo highline 1.2 tsi 2015
vw polo highline 1.2 tsi dsg
vw polo highline 1.2 tsi test
vw polo highline 1.4
vw polo highline 1.4 16v
vw polo highline 1.4 2010
vw polo highline 1.6
vw polo highline 1.6 tdi
vw polo highline 1.6 tdi dpf
vw polo highline 1.6 tdi dpf 90ps 7-dsg
vw polo highline 2006
vw polo highline 2009
vw polo highline 2010
vw polo highline 2011
vw polo highline 2013
vw polo highline 2013 india
vw polo highline 2014
vw polo highline 2015
vw polo highline 2016
vw polo highline 2017
vw polo highline 90 ps
vw polo highline ablagefach
vw polo highline adac test
vw polo highline ausstattung
vw polo highline automatik
vw polo highline autoscout24
vw polo highline baujahr 2000
vw polo highline black
vw polo highline diesel
vw polo highline diesel 2013
vw polo highline diesel 2014
vw polo highline diesel ebay
vw polo highline diesel gebraucht
vw polo highline diesel india
vw polo highline diesel price
vw polo highline diesel review
vw polo highline diesel review team bhp
vw polo highline dsg
vw polo highline eu neuwagen
vw polo highline executive
vw polo highline facelift
vw polo highline features
vw polo highline for sale
vw polo highline gebraucht
vw polo highline gebraucht kaufen
vw polo highline gebrauchtwagen
vw polo highline india
vw polo highline interior
vw polo highline jahreswagen
vw polo highline kaufen
vw polo highline km 0
vw polo highline konfigurator
vw polo highline konfigurieren
vw polo highline kopen
vw polo highline leasing
vw polo highline lenkrad
vw polo highline limousine
vw polo highline mexico
vw polo highline music system
vw polo highline navi
vw polo highline neu
vw polo highline neues modell
vw polo highline neupreis
vw polo highline neuwagen
vw polo highline nieuw
vw polo highline pepper grey
vw polo highline petrol
vw polo highline petrol 2011
vw polo highline petrol 2013
vw polo highline petrol price
vw polo highline petrol review
vw polo highline petrol team bhp
vw polo highline petrol user review
vw polo highline plus
vw polo highline price
vw polo highline price in chennai
vw polo highline price in kolkata
vw polo highline r line
vw polo highline review
vw polo highline second hand
vw polo highline shadow blue
vw polo highline specials
vw polo highline specification
vw polo highline specs
vw polo highline tageszulassung
vw polo highline tdi
vw polo highline te koop
vw polo highline team bhp
vw polo highline test
vw polo highline tsi
vw polo highline tsi test
vw polo highline tyre size
vw polo highline tyres
vw polo highline udstyr
vw polo highline usado
vw polo highline usata
vw polo highline velgen
vw polo highline video
vw polo highline vs comfortline
vw polo highline vs sr
vw polo highline vs swift zdi
vw polo highline vs swift zxi
vw polo highline weiß
vw polo highline wiki
vw polo highline xenon
vw polo highline youtube
vw polo trendline comfortline of highline
vw polo tsi highline for sale
vw polo tsi highline manual
vw polo tsi highline review
vw polo unterschied comfortline highline
vw polo unterschied trendline comfortline highline
vw polo v highline
vw polo variant highline
vw polo wersja highline

VAG RELAY INDETIFICATION

VW RELAY PROBLEM, AUDI RELAY ISSUES, SEAT RELAY TROUBLE AND SKODA RELAY DIFFICULTIES.

So, you have an electrical problem with one of your car's relays and you have no idea which one is troublesome or misbehaving because even the Bentley manual got that information wrong. Well, your'e in for a treat because I have listed several VAG relays in their "marking number order", making them easy to identify. For example, the manual lists the Motronic Engine Control Module Relay as item (J271) which is in fact Relay #428 for older gasoline powered VW, AUDI, SKODA and SEAT cars and Relay #460 for later (newer) gasoline powered VW, AUDI, SKODA and SEAT cars whereas  Relay #109 is the Motronic Engine Control Module Relay for older diesel powered VW, AUDI, SKODA and SEAT cars and Relay #120 for later (newer) diesel VW, AUDI, SKODA and SEAT cars. VAG cars have relays strew all over the car, sometimes in the engine compartment, sometimes under the dashboard, sometimes in the fuse distributor, etc, so they're not always that simple to find. However if you know what they do, then fault finding relay issues / problem,  becomes simple.

Relays with their VAG numbers inscribed on the plastic housing.

WHAT IS A RELAY?

Technically, a  relay is just a remote switch. Most of the VAG relays are 4 pronged, and the reason relays are use as remotes switches, is because its contacts can carry a lot more current than a dashboard mounted switch. Besides relays make it convenient to switch several sets of contacts simultaneously when the solenoid in energized. Relays come in all sorts of configurations among which are single pole single throw, double pole double throw, etc and can be really toublesome. Most VAG solenoids have 4 prongs, 1 or 2 regular prongs used for the solenoid winding and 2 or 3 heavy duty prongs allocated for the switch contacts that carry higher currents. Relay contacts can become intermittent after suffering consistent contact bounce. The relay solenoid can even burn out, causing the relay not to respond. The most common problem on relays is cracked or dry solder joints on the printed circuit board around the heavy duty prongs. I've also found the plastic stays that supports the metal relay contact melt due to heat build-up rendering the mechanical switch movement inoperative.

Cracked / Dry Solder joints. This is what happens inside relays.

It is also common for relay contacts to fuse/melt/weld together either in the normally open or the normally closed position.  A telltale sign is that the plastic housing is discoloured in an area and often bulged due to excessive heat where this happens. Sometimes the relay prongs heat up so much that it melts  the socket it plugs into causing the PVC/plastic to flow between the prong and socket contacts causing an open circuit. Either way, relay will have to be replaced and perhaps even the relay socket.  VW used many Multi purpose relays like Relay #1, Relay #53, Relay #204, Relay #645 to mention but a few. These can easily be used in place of most other relays should it meet the necessary current specifications.  Spade terminals connected to a short lengths of appropriate thickness wire  from each sprong and plugged into the correct relay socket slot can serve as a converter if the switch prongs are differently configured from the one you need.

VAG Engine Control Module Relay Circuit showing  the relay output powering-up the ECU.

VW Relays, SKODA Relays, Audi Relays, SEAT Relays,

Relay #1 SEAT, VW Relay Multi Use Relay ... Part No - 171 906 383

Relay #7 AUDI Relay - ABS Hydraulic Pump Relay

Relay #13 VW, SKODA Relay - A/C Relay

Relay #15 AUDI VW SEAT SKODA glow plug relay  (same as #202) ... Part No - 8A0 951 253

Relay #17 SKODA, Audi Seat VW relay  ... Part No - 171 937 503A

Relay #18 VW, Audi, Seat, Skoda, Load Reduction Relay  ... Part No - 191 937 503

Relay #19 VW, Seat, Audi  Relay - Wiper Interval Relay ... Part No - 321 955 531A

Relay 20 VAG VW Audi Skoda Relay - Rear Window Wiper Relay ... Part No - 171 955 529

Relay #21 Polo Passat, Bora, Caddy, Emergency Signal Flasher Relay ... Part No - 191 953 227 A

Relay #22 VAG, VW, Audi, Skoda, Indicator Hazards Relay  ... Part No -  431 953 231

Relay #27 Seat Relay - Belt Warning Control Module Relay

Relay #30 VW, AUDI Relay - Rear Window Wiper/Washer Relay

Relay #31 VW, Audi, Seat, Wiper Timed Relay ... Part No -  191 955 532A

Relay #33 VW relay - Headlight Washer System Relay

Relay #36 VW, Audi, Seat,  Lights Left On Buzzer Relay ... Part No -  3A0 951 307

Relay #38 VW, Audi, Seat, Skoda,  Air Conditioning Relay  ... Part No -  191 906 383A

Relay #53 VW, Audi, Seat, Skoda Relay -  Multi Use Relay ... Part No -  141 951 253B

Relay #67 VW Jetta relay - FP (Fuel Pump) Relay

Relay #68  VAG,VW, Audi,Skoda, Coasting Relay (Fog lights / Horn)... Part No -  811 919 098B

Relay #72  VW, Audi, Seat, Rear Wiper Relay ... Part No -  191 955 529

Relay #74  VAG, Control Unit Fuel Cut Off Relay ... Part No - 811 919 096G

Relay #76  VW, Audi Relay -   Double Relay ... Part No - 443927826,

Relay #79 VW Relay - Remote Rear Lid Relay

Relay #80   VW,  12v 40 Amp Fuel Pump Relay ... Part No - 191 906 383

Relay #87 VW AUDI Relay - ABS Relay

Relay #88  VW, Audi, Seat Relay - Buzzer Relay ... Part No - 443 951 307ABC

Relay #94  VW  Audi Relay - Head light Relay ... Part No - 191 906 383B

Relay #99 VW Relay - Washer/Wiper Intermittent Relay

Relay 100  Jetta, VW, Polo, Golf Relay -  SAI relay (secodary Air Injection)   (J299)

Relay #100 VW, Audi , Seat, Skoda, Golf , Bora  Beetle, Load Reduce Relay 7M0 951 253A

Relay #109  ECU Power Supply Diesel AUDI, Skoda, Seat, VW,  ... Part No - 357 906 381A

Relay #117 VW Audi Seat  Control Unit Relay Part Number 357906121

Realy #120  VW AUDI VW Diesel Engine Control module relay ...  Part No - 1H0 906 123

Relay #128  VW AUDI  Headlight Control Relay Part 7M0 941 597

Relay #131 VW Audi Seat Skoda  Timed Cooling Fan Relay Part No 357959485

Relay #134 Audi, VW,  Diesel Engine Relay Part No - 357906123

Relay #147  VW Audi Seat  Air Conditioning Relay Part No 1H0959142

Relay #149 VW Audi Seat Skoda  Rear ELECTRIC OPENING VENT WINDOW Nr 357959485

Relay #151  VW Audi Seat Skoda  Rear Fog Light Realy Part Number191945383

Relay #153 VW Audi Seat Skoda PNEUMATIC IDLE SPEED BOOST Part No357907467

Relay #167  VWAudi Seat Skoda Fuel Pump Relay With Part No 191906383C

Relay #168 VW, Audi, Aircon Retardation Relay Part No 7M0906363

Relay #169 VW Audi Seat Skoda Relay Heated Rear Window Relay Part No 7M0959627C

Relay #136  AUDI , VW GOLF, IBIZA 1.9 AAZ Engine Control Unit Relay 1H0 906 123 A

Relay #185 VW, Audi,Seat, Skoda, Relay For Starter Check Part No - 3B0 91 1251

Relay #200  VW Audi Seat Skoda Relay Part No. - 7M0 951 255

Realy #201 VW Audi Seat Skoda Relay Close Contact Relay Part  No. - 443 951 253T

Relay #202   AUDI A4/A6 VW PASSAT Relay  - Glow Plug Relay NO 202 8A0 951 253

Relay #203 VW Audi Seat Skoda GLOW PLUG RELAY FUEL PUMP Part No 8A0 951 253A

Relay #204  VW, Audi,   Skoda, SEAT Relay - Multi Use Relay Part Number 4319 512 53H

Relay #205 VW Audi SEAT Relay - Contact Close Relay Part Number 443 951 253

Relay #206 VWAudi Seat Skoda Relay For Air Con Part Number 431951253F

Relay #208 VW Relay - Contact Close Relay Part Number 8A0951253B

Relay #213  VW Audi Relay - Coolant Fan Relay 443951253J

Relay #214  Audi, VW  Relay - Cooling Fan Muli UseRelay  443951253K / 8D0951253A

Relay #215 Audi Contact Close Relay Part Number No - 4439 512 53l

Relay #216  VW Audi Seat  Relay - Contact Close Relay Part Number 443 951 253M

Relay #217 VW Audi Relay Part Number 443 951 253S

Relay #218 VW Audi Seat Skoda  Window Regulator Relay Part No 895951254

Relay #213  VW Audi   SEAT Skoda Relay - Cooling Fan Relay  443951253J Relief a4 a6 a8

Relay #219 VW PASSAT  AUDI A4, TOUAREG Relay - 12V FAN RELAY 443 951 253 AA

Relay #229  VW Audi Seat Skoda Relay - Intermediate Wiper Relay Part No 431 955 531

Relay # 236 Audi Time Control Relay Part Number 443955532A

Relay #239 VW Audi Seat Realy - Rear Wiper Washer Relay Part Number 445955529A

Relay #240 VW Audi Oil Pressure Relay Part Number 443919082

Relay #241  VW Audi Oil Pressure Relay Part Number 443919082B

Relay #259 VW Audi Seat Buzzer Relay Part Number 443951307A

Relay #267 VW Audi Skoda Magnetic Clutch Relay 443919578C

Relay #272 VWAudi Time Control Relay Part Number 443955532C

Relay #297 VW Audi Control Unit GearShift Lock Relay PartNumber 443927351B

Relay #296 VW Audi Seat Skoda  Relay For Magnetic Coupling PartNo 443919578G

Relay #301 VWAUDI SEAT RELAY Part No 4A09194714A

Relay #305 VW Audi Seat Skoda AC Compressor Control Unit Relay No 443919578J

Relay #310 Audi Relay - Oil Pressure Relay Part Number 893 919 082A

Relay #337 VW Audi Seat Skoda Relay Part No 4A0 907 413

Relay #339 VW Audi Seat Skoda Relay For ABS Part No 4A0 907 517

Relay #342 VW AUDI Audi Air Conditioning Clutch Relay Part No - 4A0919579C

Relay #351 VW Audi Seat Skoda Relay For ABS Part No 4A0907513A

Relay #355 VW Audi Seat Skoda  Relay PartNo 4A0 907 413A

Relay #357 VW Audi Skoda  Seat Cruise Control Relay... Part No - 4A0907307A

Relay #361 VW, AUDI, SEAT 1.9 TDI Relay   ... Part No - 4A0 907 440

Relay #364 Audi Seat Skoda VW Relay Part No 4A0951258

Relay #366 VW Audi Seat Skoda Relay Part No 4A0907413B

Relay #368 Audi Seat Skoda VW Relay For Heater Unit Part No 4A0 907 045

Relay # 370  VW Audi Relay Close Contact Relay 8d0 951 253

Relay #373  AUDI VW Part Number: 8D0951253A (8D0 951 253A)

Relay #377  VW Golf   Bora  Intermittent Wash Wipe, fuse Relay ... Part No - 4B0 955 531A

Relay #381 VW, Audi, Skoda, Fog Light Relay ... Part No - 431951253G

Relay #387 VW, Audi, Skoda, Head light Brake Warning Relay ... Part No - 4B0 919 417

Relay #389 VW Relay - Headlight washers Relay

Relay #390 VW, Audi, Multi Function Steering Wheel Relay ... Part No - 4B0 907 487

Relay #399  VW, AUDI,  Audi A8,  Multi Function Steering Wheel Controller

Relay #410 VW, Golf  MK4,  Lupo, Bora, Pasat, VW Polo Relay - Fuel Pump Relay 6N0 906 383A

Relay #411 VW, Passat, Jetta, Golf, Skoda , Seat, Relay ... Part No - 1J0 959 485 A

Relay #428 VW, Audi, Motronic Engine Control Module Relay (J271)  

Relay #430  VW Audi, Seat, Skoda, Relay   ... Part No -7M3 959 143

Relay #433 VW Golf, Touareg Relay - Starter Cut Off Relay, ... Part No -  3D0 951 253 A

Relay #451 VW GOLF BORA Relay - Multi Function Steering Wheel Relay control Unit  1J0 907 487A

Relay #460  VW GOLF JETTA Relay - Passat Engine Control Unit Relay ... Part No - 1K0951253A

Relay #461 VW Touran Relay - 1T2 1.9 TDI (J271)  Glow plug Relay  03G 907 282A  

Relay #460 ECU Relay,  VW GOLF MK5 JETTA Passat Audi A3 TT 1K0951253A

Relay #645 Audi VW Skoda Seat Relay - Multipurpose  Cooling Fan Relay 4H0 951 253A

SEAT CHECK ENGINE LIGHT PROBLEMS

SEAT COMMON PROBLEMS AND SOLUTIONS  

The supermini SEAT Cordoba based on the Seat Ibiza Mk2, has been around since 1993. When the Volkswagen AG took over production from the Spanish auto maker, it was  replaced by the Ibiza ST /  Seat Vario built on the same platform as the Mk4 VW Polo and the Skoda Fabia. They are available in coupe, saloon and estate in 1.2, 1.4,  1.6, 1.8 and 2.0L petrol and 1.9L diesel engines with either a 5-speed manual or 6-speed tiptronic gearbox, and were in production until 2009. These cars  were  renown  for their good performance, handling and its safety features, but like all cars, they tend to develop common problems after a few years. Pero es un buen coche para comenzar en Mexico y España.

The most common of all engine problems was engine misfiring and in the process turning on the Seat check engine light, or the Seat Ibiza engine warning light, or  Seat Altea engine warning light, or the Seat Leon engine warning light, or Seat Arosa engine warning light, or Seat Leon TDI engine warning light, or Seat Cordoba  engine warning light. The most likely cause of this problem was the coil pack or the spark plug leads which needs replacement. A telltale sign was excessive  shaking when idling. This was very prevalent when coming to a stop street or traffic light or when starting first thing in the morning. Unlike cars of yesteryear  that had a single coil and a distributor that supplied a spark to the upcoming spark plug; these cars have its own coil pack for each cylinder. More coils packs  just increased the amount of things that could go wrong, and do they go wrong.

Another common problem with the Mk4 was a lack of power which also turns on the Seat Ibiza engine diagnosis warning light or Seat Cordoba engine warning light.  The cause of the problem in most cases is  the MAF (mass air flow) sensor. A telltale sign is a lack of power at high speeds and or just  poor overall acceleration. It is always worthwhile to try and clean it with compressed air but if this didn't solve the problem, replacement is the only option.  Once repaired,  one would feel an immediate improvement on performance. 

Many Seat Cordoba window wipers also just suddenly stops working which sometimes turned out to be the wiper linkage that seized and sometimes turns out to be the wiper motor and sometimes both. Then there is the ever creaking noise sometimes sounding like an exhaust rattle coming from the front suspension when driving over speed bumps or rough surfaces. This turned out to be the anti roll bar bushes which after replacement solved the problem. A problem that plagued the automatic models is the ever noticeable red oil mark on the ground underneath the car. The origin of the leak is either gearbox seal leaking or the selector shaft seal that is leaking. Seal replacement normally stops the leak. Failure to address this problem ends up with the gear lever stuck in park with the PRDN light glowing right red on the dashboard. The gearbox  grinds when attempting to put the car into drive but will kick in with an huge thud.

Then there is the breaking distance problem on certain models (Ibiza, Toledo, Cordoba, Leon, Vario and Inca) fitted with ABS, needing a lot more force to be applied to the brake pedal to get the car to stop. The cause of the problem turned out to be tension cracks that develop in the vacuum pipe going to the brake servo near to the connections area. This is in fact a manufacturing fault that can be replaced under recall free of charge. After replacement of the vacuum pipes breaking was back to normal.

Ibiza, Altea Toledo, Leon Toloedo, Cordoba  and Alhambra vehicles fitted with a 3 and 4 cylinder pump injector engine with 2 valves per injector is prone to the bolts on the tandem pump cover that breaking off.  This was also a manufacturer  fault and vehicles were recalled to have the pump checked that was supplied by a certain manufacture.

Seat Ibiza and Seat Toledo and Seat Leon with VINs ranging from VSSZZZ1MZ1B036908 to VSSZZZ1Mz1B044227 seem to have a problem with head airbag unit which would fail to activate under certain collision conditions. Seat Altes,Toledo and Leon with 2 L TDI engine and  6 speed manual VIN ranging from VSSZZZ5PZ4R000048 to VSSZZZ5PZ4R017390 and VSSZZZ5PZ5R000026 to VSSZZZ5PZ5R103620 and VSSZZZ5PZ6R000009 to VSSZZZ5PZ6R001638  have flywheel problems that was also recalled for replacement.

The Seat Cordoba 1.9 TDI also developed starting problem when not driven for a day or two. But will eventually start after several attempts, idling very rough and smoking. In some cases it just drained the battery as well. But once she started it will start every time thereafter until left to stand for a day or two again.  This was caused by the diesel pipes sucking in air causing the diesel to flow pack towards the tank. The cause was a leaking diesel filter. A very annoying problem with some Mk4 is the drafts that comes in through door seals. It seemed that these rubber seals tend to collapsed after 5 years. Another thing is the coolant sensors / temperature sensors are generally of a very poor quality on all VW/Audi/Seat/Skoda group cars. They just tend to go faulty all the time. Surprisingly most of these problems are also prevalent in VW Polo range, after all SEAT is just another Mk4 VW Polo that has been badge engineered.