DIAGNOSTIC TROUBLE CODES

DIAGNOSTIC TROUBLE CODES

Your car has been misbehaving of late. Somehow she just doesn't seem to perform like she did in the past. It is very likely that there is a problem with your car and that she already threw an error code, now stored in its OBD (on-board Diagnostics) system. Fortunately this stored data can be retrieved via the diagnosis interface because diagnostic error codes have been standardized globally. Implying that the stored data can be retrieved with any Generic Scan Tool. Virtually every VW service center and even some private mechanics have one or more. Many private individuals have also invested in scan tools  because automotive repair cost have just skyrocketed of late hence they prefer to do the repairs themselves. I've been doing all my VW repairs for the past 8 years. 

OK, so now that youv'e done a diagnostic scan of your car, and retrieved the diagnostic scan codes, the printout looks like a foreign language. You desperately need help to understand what it means but you are no nearer to solving the misbehaving problem with the scan in hand, than you were without the scan. Don't worry, after explaining the basics of scan analysis, you will have a decent idea how to interpret your particular scan and perhaps even do the repair yourself before deleting / clearing the error code.

Low cost Diagnostic scan tools from various manufacturers.

Before we start to analyse the scan there are a few things that I need to mention. Diagnostic errors or more correctly DTC (diagnostic trouble codes) are numerous and fall into to categories, viz Generic fault codes / manufacturer-specific fault codes. However, there is a third category specific to VAG vehicles, though many mechanics also consider them as manufacturer-specific. But I will expound on this later. Fault code are divided into four categories viz, P, B, C and U One of these four alphabetical letters always precede  four numerals  and are thus referred to as an alphanumeric  code or just code for short. The P category is by far the most interesting. Both Generic fault codes and  manufacturer-specific fault codes are applicable to all OBD-II vehicles but manufacturer-specific fault code definitions vary from manufacturer to manufacturer and are also different to VAG codes.

P CODES

The P stands for powertrain, meaning the car's engine and gearbox / transmission.  So any and all preceded by a P is associated with engine or transmission problems. For example, P0100 is a powertrain code that correlates to  'mass  air flow circuit problem'. P0200 is also a powertrain code that correlates to an 'open circuit injector'. P0300 is a another powertrain code that correlates to the 'detection of random/multiple cylinder misfires'. P codes start at P0000 and range to P3999.  Generic P codes are a subset of P codes and start with either P0xxx, P2xxx and P34xx - P39xx, implying that P codes  staring at P1xxx and P30xx- P33xx are not generic but manufacturer-specific codes. 

As can be seen above, in the Powertrain system , the first digit after the P indicates  whether or not the code is generic or manufacturer-specific. The second digit identifies a specific area of the vehicle that's at fault. The powertrain components are divided into 9 distinct area as can be seen below. ( Refer to diagram below)

1xx Fault codes related to 'Fuel & Air Metering'
2xx Fault codes related to 'Fuel, Air metering & Injection Circuit'
3xx Fault codes related to 'Ignition System & Misfire Detection'
4xx Fault codes related to 'Auxiliary Emission Controls'
5xx Fault codes related to 'Vehicle Speed & Idle Control System'
6xx Fault codes related to 'Computer Output Circuit'
7xx Fault codes related to 'Transmission / gearbox related faults'
8xx Fault codes related to 'Transmission / gearbox related faults'
9xx Fault codes related to 'Transmission / gearbox related faults'

The third and fourth digits identify the specific component involved with the fault. This can be referenced from a complete list of codes that can be downloaded from various OBD sites. For example, www.outilsobdfacile.com/ www.obd-codes.com/trouble_codes/ www.launchtech.co.uk  www.trouble-codes.com/ www.automotive-technology.co.uk 

The fault code doesn't identify the actual component that's causing the fault but rather narrows it down the area that needs to be investigated. Often times the sensor that does the detection actually goes faulty. For instance, the crankshaft position sensor and camshaft position sensors are prone to failure, causing the engine to stall or  fail to start. 

OBD-II Diagnostic Trouble Codes Explained

B CODES

B stands for Body and includes the Air Bag and other mechanical / electronic components not associated with the engine and transmission/gearbox. For example, B0005 is a body error code and correlates to a 'park switch circuit malfunction'. B0530 is another body error code and correlates to a 'stuck fuel level sensor'.  Generic body trouble codes start with either B0xxx or B3xxx, again implying that B codes starting with B1xxx and B2xx are manufacturer-specific codes.

C CODES

C stands for Chassis and include the ABS and other mechanical / electronic components not associated with neither  the engine and gearbox nor the body. For example,  C0281 is a chassis error code and correlates to a 'brake switch circuit malfunction'. C0238  is a chassis error code and correlates to a 'wheel speed mismatch'. The generic network trouble codes for C start with  either C0xxx or C3xxx. C codes starting with either C1xxx or C2xxx are manufacturer-specific codes.

U CODES

U stands for User Network. Initially the U stood for “undefined” but is now network-related. For example,  U0109 is a network error code  and correlates to 'lost communication with fuel pump control module'. U0405 is another is a network error code  and correlates to 'invalid data received from cruise control module'. The generic network trouble codes for U start with  either U0xxx and or U3xxx, again implying that codes starting with U1xxx and U2xxx are manufacturer-specific codes. 

VAG CODES

Now VAG codes on the other hand  range from 00000-65535 and don't have any letters. It is just a 5 digit numeral and coincides with the list of both generic code and manufacturer specific codes. For example:-

VAG code 16385 coincides with generic code  P0001 - Fuel Volume Regulator Control Circuit Open

VAG code  16389 coincides with generic code  P0005 - Fuel Shutoff Valve (A) Circuit Open


VAG code   16434 coincides with generic code  P0050 - Oxygen Sensor Heater Bank 1/2 Control Circuit

Generic fault code P0403 equates to a VAG 16787 - EGR Valve Malfunction

Generic fault code P0571 equates to a VAG 16955 code - Brake Switch Signal Implausible 

Generic fault code P1690 equates to a VAG 18098 code - Malfunction Indication Light (K83)


Generic fault code  P1814 equates to a VAG 18222 - Transmission Pressure Control Valve open or Short to Ground 

Generic fault code P0032 equates to a VAG 000050 - Oxygen (Lambda) Sensor Heating Circuit Short to Plus 

Generic fault code P0720 equates to a VAG 17104 -  Transmission Output Speed Sensor (G195) Circuit Malfunction


Generic fault code P1517 equates to a VAG 17925 -  ECU Power Supply Relay  Malfunction 

Looking at your scan printout, especially if it's a VCDS scans, it may be quite evident that there are two or three data systems delivering the same data but in a slightly different format. The clipping below purely displays VAG codes with a numeric description.

Address 17: Instruments Labels: Redir Fail!
Part No: 6Q0 920 820 H
Component: KOMBI+WEGFAHRSP VDO V05 
Coding: 00141

6 Faults Found:
01312 - Powertrain Data Bus 
37-10 - Faulty - Intermittent
01314 - Engine Control Module 
49-10 - No Communications - Intermittent
01316 - ABS Control Module 
49-10 - No Communications - Intermittent
01321 - Control Module for Airbags (J234) 
49-10 - No Communications - Intermittent
01322 - Control Module for Multi-Function Unit (MFA) (J501) 
49-10 - No Communications - Intermittent
01309 - Power Steering Control Module (J500) 
49-10 - No Communications - Intermittent


The clipping below displays both generic and VAG error codes as well as a fault description in number code.

Address 01: Engine        Labels: 06A-906-032-BBW.lbl
Part No: 06A 906 032 RJ
Component: 2.0l R4/2V      G   6505  
Coding: 00003
   
4 Faults Found:
17837 - Circuit for Brake Vacuum Pump 
P1429 - 35-00 - Open Circuit
16452 - MAP/MAF  Throttle Position Correlation 
P0068 - 35-00 - 
16804 - Catalyst System; Bank 1 
P0420 - 35-00 - Efficiency Below Threshold
16395 - Bank 1: Camshaft A (Intake) 
P0011 - 35-10 - Retard Set point not Reached - Intermittent

The clipping below  shows VAG 5 digit codes and description numbers.

46 Address: Central Conv. Labels: 1C0-959-799.lbl 
Part No: 1C0 959 799 C 
Component: HLO Komfortgerát 1H 0003 
Coding: 00258 

3 Faults Found: 
01330 - Central Control Module for Central Convenience (J393) 
53-10 - Supply Voltage Too Low - Intermittent 
00849 - S-contact at Ignition / Starter Switch (D) 
25-00 - Unknown Condition Switch 
01359 - Internal Central Locking Switch; Passenger Side (E198) 
27-10 - Implausible Signal - Intermittent

As can be seen in two of the examples above, there are also numbers like, 27-10, 37-10, 49-10, etc. The first two digits of each set of numbers are the numeric equivalent to the text meaning 'Implausible Signal, 'Faulty  and 'No Communications' respectively. Each set of numbers ends in -10, which means 'intermittent'. Hence 27-10 means Implausible Signal - Intermittent, 37-10 means  Faulty - Intermittent and  49-10 means  No Communications - Intermittent. Fault codes can also have a -00 suffix in place of -10 which implies a definite fault (not intermittent). Occasionally you would encounter just a hyphen (-). This implies that the scan equipment could not retrieve further details about the fault and just left it blank. 

HOW TO STEAL AN AUDI

HOW TO STEAL AN AUDI, VOLKSWAGEN, SEAT OR SKODA

Gone are the days when car thieves could slim-jim a car's door, jam a screwdriver into the ignition lock and turn it with force to start the car, or alternatively cut the ignition wires and hot wire the car, and off they go. In most cases stolen cars are seldom recovered, forcing Insurance Companies to hike their premiums. Lobbying  on their part, and government efforts to reduce car theft, resulted that immobilizer and alarm systems started appearing as standard features in most cars.  I believer that it's now mandatory for all new cars sold within the European Union to have an electronic engine immobilizer installed.

IMMOBILIZER

An immobilizer acts as an anti-theft device that inhibits the car's engine from starting, unless the correct ignition key or additional electronic deactivation device is present. This concept makes hot wiring a car totally futile. If the code received from the key is incorrect or missing, the ECU disables the system until the correct key is placed in the ignition, and or the correct key code  is presented, which will allow the car to start. Such electronic devices operate  automatically and effectively prevents thieves from starting a car by hot wiring it, thus incentivising auto Insurance Companies to offer lower rates for vehicles equipped with these anti-theft devices. Be that as it may. Are immobilizers "secure" enough? Especially considering that it only reduced car theft by an estimated 40%. 

Transponder chips used in automotive immobilizer systems

Currently, electronic chips,  algorithms and data encryption systems are used to protect cars from theft. And since its inception, the electronics industry members have had ways of marking their micro chips. In most cases, with  an alpha numeric marking and perhaps a logo. Texas chips had a tiny map of Texas, Motorola had their classic M, Phillips  had an emblem composed of a globe with a doubly wavy equator with two stars in each hemesphere. There were also several other electronic chip manufacturers many of them specializing in specific equipment. But today Philips and Texas Instruments dominates the fob key transponder market with their immobilizer chips. Legacy key manufactures like JMA and Silca each formed in-house electronics departments that specifically focuses on transponder technology and vigarously compete for market share. Then there is also Sokymat, Temic, NXT, Megamos, etc, providing anti-theft transponder / immobilizer electronic devices for keys.

Turbo Key Decoder can unlock any VAG car in just 3 minutes.

A VW 3 button remote fob key fitted with a transponder and a miniature electronic circuit board essentially broadcasts an encrypted radio signal to the receiver fitted in the car's steering column, at the exact moment the driver starts the vehicle. If the signal is recognized by the receiver and the handshake is successful, it then responds by sending an encrypted signal to the car's engine control unit (ECU), enabling the car's engine to start. In Volkswagen vehicles, the miniature electronic circuit board in the fob key handles central lock/unlock and alarm activation which normally operates on the 433Mhz (UHF) frequency band, but some models  operate on either  315MHz or at 868MHz frequency band. 

Volkswagen, Audi and Seat only uses two key blade profiles, namely HU66 and HU49 on both their flat and flip keys, whereas the Skoda uses both HU66 HU49 and SK22 blade profiles. The blades and profiles are visible in the image below which can easily be decoded with a Turbo key decoder or a cheaper Lishi decoder, aka Master Key-Set for VAG for the relevant blade profile.

Volkswagen. Audi, Seat and Skoda key blade profiles.

The intricacy starts with the numerous transponders used in Volkswagen, Audi, Seat and Skoda which varies from the PHILIPS ID33 Transponder, to the PHILIPS Crypto ID42 Transponder, to the PHILIPS Crypto ID44 Transponder, to the PHILIPS Crypto ID46 Transponder,  to the MEGAMOS  ID13  Transponder and MEGAMOS Crypto  ID48  Transponder; to the Silca and JMA equivalents. Some  precoded  Megamos Crypto transponders can be coded from the VIN using the appropriate equipment, like the AD100Pro.

Megamos Crypto ID48 transponder (glass)

Having said appropriate equipment; immobilizers according to most of us are  "secure" but research hackers have found vulnerabilities in the engine immobilizers algorithm / encryption system that is supposed to protect the vehicle from theft.  Apparently said hacker hacked one of the most popularly used immobilizers  within a mere 6 hours.  He then released a white paper "Wirelessly Lockpicking a Vehicle Immobilizer" but was gagged by the High Court of London with an interim injunction from releasing his scientific article for public consumption. 

The following is an actual cryptographic hash (SHA-512) 

9d05ba88740499eecea3d8609174b444
43683da139f78b783666954ccc605da8
4601888134bf0c23ba46fb4a88c056bf
bbb629e1ddffcf60fa91880b4d5b4aca

Silicon chip transponder

What this means is that the current 48 bit encryption systems used by most car manufacturers can be easily cracked. The rolling code Hitag2  system used by Alfa Romeo, Chevrolet, Citroen, Dacia, Fiat, Ford, Lancia, Mitsubishi, Nissan, Opel, Peugot and Renault has been crack several years ago and is not secure. A 48 bit system is fractionally secure compared to the 128 bits Advanced Encryption Standard (AES) used for computer data systems which could take more than a 100 years to crack with a Quantum Super Computer. To add doom to gloom, several key decoders and key duplicators are available on the open market and you don't have to be a certified locksmith to be able to buy it, though they is quite expensive. 

"The mechanical turbo decoder can unlock any

 Audi, Volkswagen, Seat or Seat 

within 3 minutes flat".

Once the key is duplicated, the doors can be unlocked  and turning on the ignition is just as simple.  Starting the vehicles is slightly more intricate but still doable. Silca and JMA supplies systems that can do exactly that in just a few minutes. Optika, Lector and Lector Pro reads the code from the key and generates the required code.
What this means, is  that it now easier to steal a car with a manufacturer fitted immobilizer than a car with an anti theft gorilla bar attached to its steering.

Car Steering Wheel Theft proof Lock - Auto Anti-theft Retractable Lock

Laser key cutting machines  and key duplicating machines are as popular as diagnostic scanner software and it is really easy to use. I suppose its just a matter of time before crime syndicates  invest in these devices to further ply their "trade". Looks like Gorilla bars are back in vogue.

VOLVO IS NO LONGER SWEDEN'S BEST SELLING CAR

VOLVO IS NO LONGER SWEDEN'S BEST SELLING CAR

It was just announced that the Volkswagen  Golf won car of the year in Sweden for year 2016. And yes, it's the  very Scandinavian country where the iconic Volvo brand topped car sales each and every consecutive year for the past 54 years . However, for the very first time in history or Volvo or rather more exactly the same number of  years, the German designed and manufactured VW Golf outsold the Swedish manufactured Volvo in 2016.  Volkswagen Golf's accounted for almost 6% of all new cars sold, whereas the combined sales of Volvo’s V70, S90 and V90 only  constituted a mere 5.7%. But this event of Volkswagen beating Volvo at sales is not entirely unique because it happened once before. Way back in 1962, the humble Volkswagen Beetle knocked Volvo off the top selling spot by outselling Volvo. Be that as it may, Volvo still retains the largest share of the Swedish Car market, sanding at roughly 22 percent, with Volkswagen in a close second position with approximately 16 percent market share.

The smokey Ford Kuga is on fire, literally!

Despite the fallout from its diesel emissions scandal, with its cheating  device, Volkswagen AG as a whole is bouncing back, regaining market confidence after  their pledge to focus on electric power in the coming years. VW Golf is Sweden's top seller and currently their most popular car.  The VW Golf sales are  closely followed by VW Passat as the fifth most popular car, followed by VW Polo as the eight most popular car, followed by the Skoda Octavia as Sweden's tenth most popular car.

Volvo has always been known to be a "very safe car" but the Swedes have lost their national pride when Chinese firm "Zhejiang Geely Holding Group" bought the  iconic Swedish brand —Volvo — in 2010. This is probably the real reason why Volkswagen is gaining ground in Sweden? 

"Talking about safe cars or rather unsafe cars. 

The fiery Ford Kuga and the fiery Ford Everest 

are probably the unsafest cars 

on the roads today".

Ford motor company has contacted all Kuga owners by post, urging them to book their fiery Kuga's into their workshops for a free maintenance check, but not explaining the urgency of the matter. No sooner have they done this, when four more Ford Kuga's burst into flames during the same amount of days. According to Ford, it appears that the issue is limited to their 1.6-litre EcoBoost engine but according to owners somehow their Everest is also affected. About a year ago a Ford Kuga driver was  burnt beyond recognition in Durban,  and to-date as many as 40 Kuga fiery incidents have been reported.


1) Ford Kuga owner leaps from burning vehicle in Durban.
2) A PE family is in shock when their Ford Kuga burst into flames.

3) Husband and wife watched their Kuga burnt out.

A all new Kuga hot-rod in full glory

Kuga with frostbite after bursting into flames

A fiery Ford Kuga making like a Volcano

Peculiarly most of the burnt-out Kugas are white in colour.

If it wasn't for the Original Ford Kuga Mag, this burnt out stack could easily
have been mistaken for a Volkswagen vehicle.

Virtually unrecognizable but is definitely a Kuga

From Ford to ashes and from Ford to dust.

It looks like a volcanic eruption but it's really a Ford Kuga

Ford Kuga front-end totally destroyed

However owner reports say that Fords bursting into flames is not limited to the Ford Kuga  EcoBoost Ambiente but rather prevalent on Ford Everest 3.0 SUV as well.  Ford motor company is facing a huge backlash and a potential class-action lawsuit over Kuga fires because Ford Kuga vehicles owners across South Africa are proressively growing concerned over the spontaneously combustion of their vehicles. Yet Ford Motor Company is still trying to dodge burning issue of recalling their Kuga range. The issue that VW went through during its emission scandal is going to be pale in comparison to what awaits Ford Motor Company because there was loss of life. The pics below are just some of the Ford Kugas that were engulfed in flames.

Ford Kuga making like a chimney

 A completely Toasted Ford Kuga

A Ford Kuga imitating a cable.

Fortunately, and all thanks to God, that Volkswagen vehicles don't burst into flames as often as Ford Kuga's do. Below are some pics of Volkswagen vehicles that suffered the same fate as the cars above.

1) A Volkswagen Polo on fire in Bo-kaap, Cape Town
2) A Volkswagen Polo Vivo caught alight outside the Punjab National Bank in India.
3) A VW Polo hosed down by its owner.

A VW Polo caught alight on the south bound R102 in KwaZulu Natal 

A VW Jetta completely engulfed in flames in Verulam-KwaZulu Natal. 

A VW Polo taking time out.

In a certain sense  every car is a potential  / ticking time bomb, considering it is propelled by highly a inflammable liquid like petrol, or diesel,  or LP gas in the presence of engine oil, and other combustible materials like cloth, foam, pleather, rubber, PVC and paint. With a battery powered high current electrical system capable of igniting electrical fires, through arcing or an electrical short circuits acting as a trigger. And Fuel spillage from a burst pipe on a hot engine presenting another trigger amongst others. This can be equated to storing a box of matches with the gunpowder in the same keg, whiles we rolling on it. 

However, if safety standards are observed to the hilt, accidents will be reduced to an absolute minimum. Case in point, the Samsung S7 with its overheating and self-combusting properties has causes many a house to burn down and likewise many a car has caused its driver severe injuries some of whom burn to death.

VCDS

VCDS

AUTOMOTIVE DIAGNOSTICS

Over the past few years, I've often referred to VCDS and diagnostic scans in my blogs. For the life of me, it never dawned on me that the vast majority of Volkswagen, Audi, Seat and Skoda  vehicle owners have  no idea what it is, have never heard of VCDS, let alone know what it does. Some has never even seen a diagnostic scan of their own car. I sincerely apologize for the confusion it may have caused.  So the rest of this installment will be devoted to explaining what VCDS is, specifically for the benefit of the masses. But before I do so, I need to sketch a picture as to why car manufacturer are obligated by law to  install on-board diagnostic OBD systems into each and every car they manufacture. 

As long ago as 1946 the State of California (USA) realized that automotive vehicles significantly contributed to the rising levels of air pollution, and passed legislation to establish 'air quality emission standards for motor vehicles'. It is noteworthy, that the very first Volkswagen emission controlled engine was in fact the 1963 Type I VW Beetle engine. It employed a system known as Positive Crankcase Ventilation (PCV) to control its crankcase emissions.  During the 1970's the United States Environmental Protection Agency raised concerns over the general degradation of air quality, though they were especially concerned over the health and environmental impacts of NOx. 

NOx is an abbreviation that refers to the entire family of nitrogen oxides, among which are nitrogen dioxide, nitrous oxide, nitrates, nitric oxide  and nitric acid . NOx is known to aggravate asthmatics, can cause lung tissue diseases and reduction in overall lung function. When NOx reacts with and sulfur dioxide and other substances in the air, it eventually comes down to earth in the form of acid rain. Acid rain is damaging our vegetation  by reducing our crop yields substantially. It also causes our lakes and streams to become acidic which is totally unsuitable to many varieties of fish, shellfish and other aquatic plants and animals. Nitrous oxide emissions also add to the already high level of greenhouse gas responsible for the gradual rise in the earth’s temperature — aka global warming. But that's, just the tip of the ice-berg, because the issue is far worse and is of serious concern. In a nutshell the Federal and State Clean Air Act galvanized the rest of the world in the consciousness to reduce their carbon footprints. 

As a follow up to Positive Crankcase Ventilation (PCV) of 1963, various parts of the automotive fuel and ignition systems were modified in an effort to reduce exhaust emissions. New systems were also added while existing systems were modified to reduce fuel tank ventilation system, tailpipe and crankcase emissions. Electronics was introduced and CDI (capacitive discharge ignition) systems made their appearance and overtime technology further transformed the  four-stroke internal combustion engine. Carburetors and mechanical fuel injection gave way to hydraulic / electronic  fuel injection. Coils, points and condensers gave way to contact-less electronic ignition systems, introduced by Bosch. The Bosch D-Jetronic system was followed by Bosch  K-tronic, then the Bosch Digifant. At some point  the electronic ignition system and the electronic fuel injection were combined which gave rise to the Bosch  Motronic engine management system. 

The main objective of an engine management system is to accurately control the fuel flow and the ignition timing whilst keeping emissions to a minimum. Though various other support systems are needed to make the combustion process occur continuously. For example, crank drives the valve-train that operates the valves, the lubrication system pumps the oil to keep the engine from overheating, the cooling system reduces heat of the oil using the radiator and fan, and the electrical system supplies the voltage and current. This allows the engine management system to deliver the exact quantity of fuel, and delivers a spark at the precise moment to match the air demands of the engine — the stoichiometric ratio.

All this technology, with the help of the IEEE, led up to the  first generation OBD (On-board Diagnostics) that used Diagnostic Trouble Code (DTC) retrieval via blink code. During the successive years  further legislation was  put into place, meanwhile OBD matured  and superseded by the stringently modified OBD-II (On-board Diagnostics 2nd generation)  which has been around since 1996. In Europe OBD-II is known as EOBD-II and the emission scandal involving Volkswagen AG since 2014 revolves around them lying about the amount of CO2 emitted by their cars and for fitting a cheating device to some of their both diesel and petrol vehicles, that actually failed its 'readiness test'.

The Readiness test is essentially a group of eight (8) electronic monitors (circuits)  that oversees the correct functioning of various emission related components fitted into all modern day cars.  Each of these operational test needs to be within the legislated specification. When there is a problem with any one monitor, it will set a binary "1" in the readiness code. If there is no problem or it passes a test, it would set a binary "0" in the readiness code. Even though emission monitoring  was the imputus for OBD-II, it wasn't limited to emission monitoring. Since a computer ECU (electronic Control Unit) was needed to  oversee the emission monitors, it was expedient to put it to other uses as well, like engine management. 

As such, the electronic control unit (ECU) was renamed Engine Control Unit (ECU). The computing power of the ECU was underutilized, since its cost certainly wasn't justified by the 8 menial tasks of emission monitoring, so manufactures started adding bells and whistles and other creature comforts. The ECU increased from a 38 pin version to and 80 pin version in a matter of years. The ECU can store information and has a non-volatile memory where it stores the DTC (Diagnostic Trouble Codes) whenever it detects a problem. The ECU also has another  memory where it stores maps of the driver's driving peculiarities which is erased when the battery is disconnected. The driver is also alerted when there is a problem by one or more instrument panel lights that turn on, or start to blink. When this happens a trouble code is stored which can assist the mechanic in solving the problem.

The bells and whistles were so many that their control needed to be grouped and separated and the rest of the control modules were introduced. Hence ECU (Engine Control Module, TCM (Transmission Contol Module), ABS (Antilock Braking System) module combined with  EDL (Electronic Differential Lock), ASR (Anti Slip Regulation) and  EDL (Electronic Differential Lock), Central Electronics Module, Airbags Module, CAN Gateway Module, Instrument Module, Central Convenience Module, Seat Memory Module, Xenon  Module, Auto HVAC Module, Interior Monitor Module, etc... 

These modules are also distributed throughout the car, sometimes placed in the most obscure places with very limited access; and all these modules are also networked (interconnected) on a bus system  called CAN Bus. Individual modules have also been given some sort of intelligence (protocol) so that they can interface with diagnostic equipment. To simplify,  it can be compared to  a land line telephone extension that can communicate with the switchboard using internal control codes. Each module has its "own telephone number" with the gateway module acting as the switchboard and when a diagnostic device is connected, it can communicate with the requested module via the gateway exchange. 

Having this glut of electronic modules on-board means a glut of sensors and a glut of actuators that accompany them; amongst which are the Engine Crank or Cam Position/Speed sensor, Intake Air Temperature (IAT) sensor, the Throttle position, the Coolant Temperature (CLT) Sensor, the Throttle Valve Control Motor, the cooling fan motor (actuator), the Fuel Pressure Regulator (actuator), the Injectors (actuator), the ignition coil (actuator) and the Oxygen Sensor (O2S) (actuator), to mention but a few. 

With all these extra electronics devices that can go faulty or rather will go faulty at some time or the other,  they will need to be repaired;  and since circuit board level repairs are done at a fairly high level, beyond the abilities of average auto technician, hobbyist mechanical or DIY car owner, module replacement is the only option. In order  to determine which component has gone faulty and which module is responsible for controlling it,  without some sort of diagnostic device is near to impossible. 

So as part of the OBD-II standard, was that vehicle manufactures were obliged to install a diagnostic port in the drivers cockpit area for such diagnostic equipment to interface with the Gateway Module. This port is called the DLC (Data Link Connector). And that's were the VCDS cable plugs into. The VCDS software allows you select your vehicle from a list of VAG vehicles then gives you an option the autoscan. The scan below  is a sample of what can be expected, except that if there is a problem with the vehicle, it will be highlighted in red. Were you see  'No fault code found' is where the fault codes will be listed. The P codes can then be analysed / interpreted and the necessary repairs can be carried out.

SAMPLE SCAN

Chassis Type: 9N (9N - VW Polo (2002 > 2010))
Scan: 01 02 03 08 09 15 17 19 25 37 44 45 46 56 76

VIN: AAVZZZ9NZ8U0XXXXX   Mileage: 221080km/137372miles
-------------------------------------------------------------------------------
Address 01: Engine        Labels: None
   Part No SW: 03C 906 057 AK    HW: 03C 906 057 M
   Component: BOSCH ME7.5.20      0707
   Revision: 21H01---    Serial number: VWZ7Z0G555XXX
   Coding: 0000075
   Shop #: WSC 31414 000 00000
 
No fault code found.
Readiness: 0000 0000
-------------------------------------------------------------------------------
Address 02: Auto Trans        Labels: 09G-927-750.lbl
   Part No SW: 09G 927 750 GH    HW: 09G 927 750 GH
   Component: AQ 250 6F           0930
   Revision: 00H67000    Serial number:            
   Coding: 0000072
 
No fault code found.
-------------------------------------------------------------------------------
Address 03: ABS Brakes        Labels: 6R0-907-37x-ABS80.lbl
   Part No SW: 6Q0 907 379 AF    HW: 6Q0 907 379 AF
   Component: ABS 8.0 front   H05 0002
   Revision: 00000000    Serial number: 00000000000000
   Coding: 0002292
 
No fault code found.
-------------------------------------------------------------------------------
Address 08: Auto HVAC        Labels: 6Q0-820-045.lbl
   Part No: 6Q0 820 045
   Component: Klimaanlage        X0850
 
No fault code found.
-------------------------------------------------------------------------------
Address 09: Cent. Elect.        Labels: 6Qx-937-049-C.lbl
   Part No: 6Q0 937 049 F
   Component: 0009 BN-SG.         2S36
   Coding: 17550
   Shop #: WSC 31414

No fault code found.
-------------------------------------------------------------------------------
Address 15: Airbags        Labels: 6Q0-909-605-VW5.lbl
   Part No: 6Q0 909 601 F
   Component: 05 AIRBAG VW5       0010
   Coding: 12341
   Shop #: WSC 31414

No fault code found.
-------------------------------------------------------------------------------
Address 17: Instruments        Labels: 6Q0-920-xxx-17.lbl
   Part No: 6Q0 920 825 P
   Component: KOMBIINSTRUMENT VDO V06
   Coding: 00141
   Shop #: WSC 31550

No fault code found.
-------------------------------------------------------------------------------
Address 19: CAN Gateway        Labels: 6N0-909-901-19.lbl
   Part No: 6N0 909 901
   Component: 01K1 GATEWAY CAN    2S36
   Coding: 00015
   Shop #: WSC 31414
 
No fault code found.
-------------------------------------------------------------------------------
Address 25: Immobilizer        Labels: 5J0-920-xxx-25.clb
   Part No: 6Q0 920 825 P
   Component: IMMOBILIZER VDO V06
   Coding: 00141
   Shop #: WSC 31550
 
No fault code found.
-------------------------------------------------------------------------------
Address 44: Steering Assist        Labels: 6Q0-423-156.clb
   Part No: 6Q0 423 156 AB
   Component: LenkhilfeTRW        V270
   Coding: 10110
   Shop #: WSC 31414
 
No fault code found.
-------------------------------------------------------------------------------
Address 45: Inter. Monitor        Labels: 6Q0-951-171.lbl
   Part No: 6Q0 951 171 C
   Component: Innenraumueberw.    0020
 
No fault code found.
-------------------------------------------------------------------------------
Address 46: Central Conv.        Labels: 6Q0-959-433.lbl
   Part No: 6Q0 959 433 E
   Component: 67 Komfortgerát     0002
   Coding: 00018
   Shop #: WSC 31414

No fault code found.

End   ---------------------------------------------------------------------

VCDS

VCDS stands for "VAG-COM Diagnostic System" and it is a dongle based hardware cable sold by Ross-tech governed by intellectual property rights. It pairs with Ross-tech's freely downloadable and regularly updated Windows based computer program that interrogate your vehicles on-board modules. However, the software needs to be registered on-line in order to take benefit from the regular upgrades.  This software provides a GUI with menus to scan the vehicle, that allows you to view Fault Codes, Measuring Blocks and view VAG-Scope data. It also permits you to clear any Fault Codes, and recode a module after  replacing it, log Data to a CSV file,  perform Basic Settings and Output Tests. And so much more. It is probably the most versatile tool to tackle any Volkswagen, Audi, Seat or Skoda repairs. Any auto workshop specializing in VW vehicles that doesn't have VCDS is at a loss, even if  they have a Launch X431, or TOAD, or Autoboss V30, the MaxiDAS DS708, etc. VCDS is specific to VAG vehicles and personally I'm very impressed with  its functionality, and I tip my hat to the Ross-Tech team.  

However, the "high price" of their cable has permitted several competitors to compete with them, producing a clone cable that works with Ross-Tech software. I'm not saying that the price of the cable doesn't justify its capabilities but if the price was more manageable for non-USA based VW owners, virtually every VW, Audi, Skoda, Seat owner would feel obliged to invest in said cable; and at the same time Ross-Tech will get rid of all the clone shysters. the same cable and software works admirably of Bugatti, Lamborghini, Bentley, Porsche and for them price is not an issue. Being a US based company Ross-Tech wants payment in USD but the USD to ZAR is  currently sitting at 1:14 and I'm certain most VAG car owners paying in another currency that don't convert favorably with the USD may have similar reservations. Enough said, go get that cable!  

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