PETROL vs DIESEL vs ELECTRIC VEHICLE COMPARISON

PETROL, DIESEL, ELECTRIC VEHICLE COMPARISON

Owning a VW Polo is fairly easy but when the exorbitant costs of unforeseen repairs and regular servicing are added, it becomes really expensive. To make matters worse, with the regular petrol price hikes, maintaining that VW Polo can become a bit of a burden.  The distance traveled by the average motorist, based on "official trade figure"  is estimated at 20 000Km per annum which directly translates to about 1667km per month or 55 km per day. At the current price of petrol (R12.89 per litre), that 55km would cost you about R43.00 subject to your Polo's Km/litre average consumption and your personal driving style. Extrapolated over a period of one year would cost you a cool R15,480.00-plus per annum and over the 60 months finance period, a whopping R77,400.00.

Volkswagen  e-Golf EV Charger Connection

Suddenly a diesel powered VW Polo TDI seems more financially attractive, especially considering that its fuel consumption of 4.6 litres / 100 km is far lower than the 5.9 litres / 100km of the low end VW Polol 1.4 Trendline. If truth be told, its a saving of at least 25 percent comparatively speaking but it's really  not that cut and dried.  My hesitancy towards a Diesel Vehicle gravitates around the fact that Volkswagen as a company had 'cheated on the fuel consumption and emissions figures globally', so I'm wondering how true these stats released by Volkswagen really are. Surprisingly, independents tend not to do comparative consumption studies or rather if they do, they don't make the results public. However, my consolation is based on my wife's Mercedes Benz C250D,  that uses a sight less fuel than her previous petrol powered C230E model over the same distance. Besides, virtually every heavy duty delivery vehicle out there is diesel powered because big business would invariably choose the more economical option. 'Diesel vehicles also tend to be less troublesome than petrol powered trucks'. They may not be as fast as their petrol powered versions but they have enormous torque, far great than their petrol counterparts. Then there is always the turbo version to consider that is much faster. Be that as it may, I'm not completely convinced whether or not to go that route.

Petrol and diesel fuel consumption comparison chart

There is a third alternative that I should explored and that is an electric powered vehicle. I quite like the VW e-Golf because its completely silent. It goes up to an estimated 133km per charge which I deem sufficient for short distance city driving. Unlike other manufacturer's purpose built electric cars, the VW e-Golf is essentially a normal VW car with an electric motor sitting in place of a petrol or diesel engine, with the fuel tank space occupied by its battery pack. Several car manufacturers are currently producing a small number of electric vehicles but it's painfully obvious that their range will expand in the coming years. So it's a good idea to embrace the newer zero emissions electric technology now, rather than later, in preference of further polluting our eco-system  with carbon dioxide emissions. But these EV's are a lot more expensive than both the petrol and diesel versions and the cost of electricity for charging its lithium-ion batteries still needs to be added. There is a likelihood that government will subsidize electric cars above a certain price range. It would probably work along the lines similar to the Eskom subsidy which is available to those home owners who intend installing a heat pump in their homes. My hesitancy revolves around recharging the EV when not near the home-based power unit. Regardless,  it makes more sense to buy the electric car, rather than a petrol or diesel car? My biggest concern though, is that lithium-ion batteries are still in its infancy or rather hasn't  properly matured yet. Though, there is a battery leasing option that comes at a monthly cost which will bring the overall monthly cost to more than than of maintaining a diesel VW Polo. Somehow this EV isn't looking that great anymore. But what I need to say is that I am very impressed by the distance that the Tesla can go on a single charge, as well as the overall quality of their new battery pack.

This impressive 115-hp electric motor with 269nm of torque makes for a really enjoyable drive.

EV Fuel Cost Comparison Example

	Units	BE	Petrol	Diesel
Combined Fuel Efficiency		150Wh/km	8L/100km	6L/100km
Annual Mileage	km	120,000	20,000	20,000
Annual Fuel Requirement	Litres	0,00	1600	1200
	kWh	2,400	n/a	n/a
Energy / Electricity Prices / Unit	Litre /KW	11.75	12.98	10.69

HOW TO FIX AN EPC PROBLEM - CONTINUED

HOW TO FIX AN EPC PROBLEM, - CONTINUED

The final note on the preceding blog installment ended on 'scan for Diagnostic Trouble  Codes with a scan tool'. However before we start scanning it is important to note, that Vehicles from year 2000 are fitted with an EPC (Electronic Power Control) system, hence this exposée only applies to cars fitted with a obdii 16 pin female connector, identifiable by its  normally purple core, roughly the same purple of the 6-pin mini-DIN connector  of a personal computer keyboard.  This EPC system / Drive-by-Wire circuit (implying no throttle cable) is also known as the torque circuit. The EPC system controls the EPC light  which turns on if and when there is the slightest malfunction  in the Drive-by-Wire circuit. Any such fault will more than likely generate a DTC (fault code) in the ECM, which is stored in its non-volatile memory, meaning even if the battery is disconnected afterwards the DTC (fault codes) will persist. However, also note that when the battery is disconnected all driver learnt values particular to your driving style, will be erased. Disconnecting the battery may require resetting the convenience electronics, such as alarm, interior lights and the radio. So, most importantly if you don't have the radio code, practice caution because the radio will permanently lock-up hence it's a good idea to use a jumper battery or perhaps even a battery charger to maintain battery power whilst replacing a battery. Or get the code from your service center.

Whilst any problem in the torque circuit is  normally responsible for turning on the EPC light,  the EPC light may also turn on for some other non-emission related engine faults.  When a combination of emission-related and EPC-related fault is encountered, both the MIL and EPC lights may turn on. This alone give one a good idea of whether or not the engine problem is purely torque related or part of an emission-relate issue.

Most pure torque circuit EPC faults are accompanied by Limp-Home Mode which revolve around the basic settings for the Electronic Throttle Control Valve Adjuster, Idling Control, EPC Adaptation and the  Accelerator Pedal Position Senders. Their values are stored in the ECU normally from group 60 - group 62 of the Bosch ME 7 and newer ECUs, however the actual group may vary subject to make, model and engine capacity of the vehicle. For example. Jetta, Polo, Audi TT, etc, EPC adaptation exists at group 060 - group 062, whereas these values may be stored in group 098 for some VW Passat and Audi A4, S4, B5.

Group=060, Adaptation Epc-system
Group=061, Epc-system (1)
Group=062, Epc-system (2)

Emergency Running or Limp-Home Mode

Both Bosch Motronic and Siemens Simos ECU have two emergency running modes to compensate for accelerator pedal sender failure. The first mode triggers when the primary sender G79 (Sender -1) accelerator pedal sender fails, and the second mode triggers when both G79 and G185 (Sender -2- redundant sender) accelerator pedal senders fail. In the first case with one accelerator pedal sender failing, the accelerator position is limited to a predefined value (limp mode) idling speed while some comfort functions will be disabled,  the Air Conditioner for example. By which time EPC light would have already illuminated. However, when the second emergency mode triggers the engine runs only at idle speed. It would be exactly like disconnecting / removing the accelerator pedal completely. On the occasion that I replaced my accelerator pedal, I started the engine and to my surprise it started perfectly normal and idled at a normal rev. So the conclusion is when both accelerator pedal senders / potentiometer fail, it gives you the same, exact, identical symptoms of a physical steel accelerator cable that snapped. Considering a throttle cable is the single most important part of the throttle system in a car engine. So when it breaks the car will idle, but will not rev. The EPC system mimics the pysical cable exactly or as near as dammit.

Siemens Simos ECU J361 with pin connections

Looking at the diagram for accelerator pedal senders G79 and G185, pins 50 and 19 are inputs from their respective highside driver 5V supplies with pins 18 and 45 of the ECU microprocessor are their independent internal earth connections. The two variable voltages at pins 51 and 64 are the inverse of on another. Essentially G185 (secondary) is working as a backup to G79 (primary). Inputs at pins 51 and 64 are constantly monitored by the ECU microprocessor could range from sporadic to too high or too low, to intermittent to absolutely not there. The  ECU microprocessor with its built-in Watchdog Supervision Safety Logic monitoring performing plausability checks for voltage regulation, Over/Under voltage levels, intermittent voltage levels. If for any reason that the calculations based on its internal algorithms do not correspond to its internally stored and expected values either the watchdog processor or the  Main Processing Element enable   a secondary shutdown path to all equipment under its control. In a nutshell, limp mode.

Constant movement of the gold plated contacts on the potentiometer slider eventually wears through and becomes intermittent especially if the vehicle has attained a high millage, considering  how may times the accelerator pedal has been stepped-on and released. It can be roughly compared to a volume control that's gone scratchy from constant use, when it finally worked through its carbon track and makes intermittent contact.  I've known physical  steel throttle cable to last a lot longer than its electronic counter part but they do have a tendency to fray and get stuck inside its sleeve especially when going at high speed, which is kinda dangerous -even life threatening.  With the EPC system this will not happen, rather if the "electronic steel threads fray" the microprocessor shuts the system down by switching over to its stored alternative values.

Looking at the diagram for G188 and G187 it can clearly be seen that they share a common 5v supply (pin 91) and a common earth (pin97) with the outputs from pins 90 and 92 acting as inputs to the ECU microprocessor that control for the throttle valve actuator motor. These inputs are also constantly monitored by the ECU main Processor and its companion watchdog processor. Noting once again that G188 and G187 act as angle sensors much like that of the accelerator position senders. The concept and principal is exactly the same as that for the accelerator potentiometers. When any discrepancy is detected, a shutdown path is enabled which presents itself to the motorist as a car that won't rev. Then there is G61, the knock sensor. Any  knock higher or vibration outside of that expected by the ECU on pin 102 will also enable a shutdown path and sequence limp mode. 

Accelerator 6 pin plug and harness for VW, Golf, Skoda, Fabia, Audi etc.

Accelerator Pedal 6 Pin Plug Connector Wiring Harness for VW, Amarok, Beetle, Eos,
Lupo, Polo,Touareg, Sharan, Transporter, Electronic  - 3B0 972 706

Based on this, the inputs and outputs from these three components are vital to the correct functioning of any Drive-by-Wire vehicle. So when a fault occurs and guided by error codes, it is important to ensure that there is wired continuity between these components and the ECU connector. Wiring harnesses are subjected to a fair amount of shaking and can break inside of the PVC sleeving. Especially sensitive is the 6 pin Electronic Accelerator Pedal Plug Connector Wiring Harness for VW Polo, Golf, Audi, Skoda, Fabia. VW part number - 3B0 972 706. This replacement part needs to be soldered onto the  wiring harness after cutting off the original plug.

VW LOGIN CODES

VW LOGIN CODES 

The "login" codes listed below work on many of the following Volkswagen vehicles listed in alphabetically. In order to use them you need a scan tool with the appropriate data connector plugged into your car's DLC connector.  VCDS software and its dual-K+CAN cable is probably your best option but is fairly expensive compared to the other ranges of DIY scan tools.  NB! Use these codes below at your own risk. If you don't have the necessary knowledge or expertise to make adaptation changes to your car's internal electronic module then it's best to leave them alone and refer these changes or logins to an automotive  professional, or at least someone knowledgeable about OBDII Diagnostic Trouble codes (DTC), vehicle  modules, intelligent sensors, the binary system, electronics and data link protocol transmission. These are extremely helpful if you've bee having one heck of a time trying to "login" to your instrument cluster to adapt some keys. Used incorrectly could turn your ECU into a brick so practice caution.

Dual-K & CAN Ross-Tech VCDS kit

Volkswagen:- (VW) Caddy (9K chassis) 1996 - 2003 and newer
Volkswagen:- (VW) Caddy (2K chassis) 2004 and newer
Volkswagen:- (VW) Corrado  and newer
Volkswagen:- (VW) Crafter (2E chassis) 2006 and newer
Volkswagen:- (VW) Eos (1F chassis) 2006 and newer
Volkswagen:- (VW) Fox/Spacefox/Sportvan/Suran (5Z chassis) 2005 and newer
Volkswagen:- (VW) Gol/Parati/Saveiro (5X chassis) 2000 and newer
Volkswagen:- (VW) Golf/Jetta II (19E chassis) 1983 - 1992
Volkswagen:- (VW) Golf/Jetta/Vento/Cabriolet III (1H chassis) 1992 - 1998 and newer
Volkswagen:- (VW) Golf Cabriolet IV (1E chassis) 1999 - 2002
Volkswagen:- (VW) Golf/Jetta/Bora IV (1J/9M chassis) 1998 - 2006
Volkswagen:- (VW) Golf/Jetta/Bora V (1K/5M chassis) 2004 and newer
Volkswagen:- (VW) Golf/GTI/Jetta (1K/5K chassis) 2010 and newer
Volkswagen:- (VW) Golf Variant/Wagon (1K chassis) 2007 and newer
Volkswagen:- (VW) Golf Plus (5M chassis) 2005 and newer
Volkswagen:- (VW) Golf Mk.6 (5K chassis) 2009 and newer
Volkswagen:- (VW) LT (2D chassis) 1996 and newer
Volkswagen:- (VW) Lupo (6E/6X chassis) 1999 and newer
Volkswagen:- (VW) New Beetle/Cabriolet (1C/1Y/9C chassis) 1999 and newer
Volkswagen:- (VW) Passat (31/3A chassis) 1988 - 1994 and newer
Volkswagen:- (VW) Passat (3B chassis) 1997 - 2005 and newer
Volkswagen:- (VW) Passat (3C chassis) 2006 and newer
Volkswagen:- (VW) Passat CC (35/3C chassis) 2008 and newer
Volkswagen:- (VW) Phaeton (3D chassis) 2002 and newer "facelift",  2007 - 2008)  
Volkswagen:- (VW) Polo (6N/6N2 chassis) 1994 - 2002 and newer 
Volkswagen:- (VW) Polo (9N chassis) 2002 -2010
Volkswagen:- (VW) Scirocco (13 chassis) 2008 - 2009 and newer 
Volkswagen:- (VW) Sharan (7M chassis) 1995 and newer
Volkswagen:- (VW) Tiguan (5N chassis) 2008 and newer
Volkswagen:- (VW) Touareg (7L chassis) 2003 and newer
Volkswagen:- (VW) Touareg (7L6 chassis) ( 2007 and newer
Volkswagen:- (VW) Touran (1T chassis) 2003 and newer
Volkswagen:- (VW) Transporter (70 chassis) 1991 - 1996
Volkswagen:- (VW) Transporter (7D chassis) 1997 - 2003
Volkswagen:- (VW) Transporter (7H/7J chassis) 2003 and newer


ENGINE
TDI Engine adaptation login = 12233 ( 4 cylinder MSA12 and newer)
EDC17 Security Access code =  12233  
EDC15/16 Fuel cooling Activation code =  10000 
EDC15/16 Fuel cooling De- activation code =  10001
Delete FMA Learning map  = 10008 
Switched EGR off  for next driving cycle = 10011 
DPF emergency regeneration V6 = 10016 
DPF emergency regeneration 4 Cyl  = 21295
Legal top speed limiter disable (AP07) = 28575
Teach differential pressure transmitter = 30605 

UDS Short Trip password = 27971
ME7 ECU Login Codes =  07825
ME7 ECU Login Codes = 01283
ME7 ECU Login Codes = 11500 Default coding
ME7 ECU Login Codes = 11223
ME7 ECU Login Codes = 11463
ME7 ECU Login Codes = 11501
ME7 ECU Login Codes = 12233
ME7 ECU Login Codes = 33162
Other  ECUs = 26262
Golf 1,6  FSI  = 10011 
Login codes for engine type AEL = 22158
Common Rail - disable top speed limiter = 10111
01283 Cruise Activation "older" vehicles
Activate ACC = 10002
Diesel particulate filter Adaptation  = 10016
Cruise Control Activation  = 11463  
Diesel particulate filter Adaptation = 21295
Special Customer Services login = 45678

ABS

Adaptation access  MK60 = 00212
Adaptation access  NDBW = 01025
Adaptation access  DBW = 04097
Adaptation access  SPECIAL A6 = 09399
Adaptation access  FWD = 13204
Adaptation access AWD = 13504
Adaptation access  AWD ESP = 18446
Adaptation access  MK60 = 19469
Adaptation access  FWD ESP = 23049
Adaptation access  General = 27861
Adaptation access to basic settings = 40168

AIRBAG

Airbag Adaptation Enabling login = 20324

INSTRUMENT

Instrument Cluster Adaptation Login = 13861

CENTRAL ELECTRONICS

Central Electronics Adaptation Enabling login = 21343
Activate Cruise Control Adaptation Login = 11463
De-activate Cruise Control Adaptation Login = 16167
Activate Cruise Control Adaptation = 13647  
NB! The  Cruise Control System  activation  Drive-by-Wire throttle systems will vary for different engine types.

STEERING

Steering Angle Sensor Adaptation Login = 40168

SUSPENSION 

General Login = 31564
Transport Adaptation Activation = 10273
Transport Adaptation de-activation = 41172

 

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.

ELECTRO-HYDRAULIC POWER STEERING FAILURE

ELECTRO-HYDRAULIC POWER STEERING FAILURE 

In a matter of just a few short days, I've received a flurry of assistance requests from several VW owners,  all of whom seem to have power steering issues of some sort or the other. These issues ranging from complete failure of power steering to intermittent steering assist, to stiff and hard to steer. Among  the vehicles affected are VW Jettas,  Volkswagen transporters, Volkswagen Passats,  VW MKIV  TDI's and Golf Mk5s. Unfortunately specifics about steering problem can vary tremendously because some VAG vehicles are Hydraulically controlled, whereas some are electronic and others are ally controlled, all of which use slightly different technologies and components often spacely dissimilar.   

This implies some vehicles will have a Power steering pump as part of the steering rack assembly whereas others will have a power steering motor / hydraulic fluid reservoir a good meter separated from the steering rack. The following is  a general overview of the operation of VAG power steering systems. But what all these systems have in common, is the dreaded yellow steering light on the instrument panel which lights up for a 3- 4 seconds when the ignition is switched on but goes out after the engine is started. This is part of the self test that checks all electronic modules and mechanical mechanisms are synchronised to work together in harmony. However when the Servotronic warning lamp K92 stays on after the engine is started, there is definitely a fault with the power steering system.


When this happens it is a good idea to book the car in for repairs or do the repairs yourself because it could be quite  expensive.  Either way get the vehicle off the public road because loss of steering while driving can be very dangerous if not fatal especially going around corners because of the possibility of over steer.  An electro-hydraulic power steering system is fairly intricate because its control modules are interconnected. The Power steering control module controls the hydraulic pump motor which produces the hydraulic pressure needed for the steering servo assistance. But in order to this, it needs signals from the 'Powers steering sensor' which is located in the steering column and from the speedometer sensor via the 'Instrument cluster control Module' which is responsible for turning on the yellow steering wheel symbol should there be a problem. And lastly the Power steering controller also needs the engine speed data from the 'Motronic control Unit'. It also needs a 12V supply from terminal 30 as well as 12 volts supply from terminal 15 and of course an earth connection. The power wires are fairly thick and chunky which implies high current delivery. Poor electrical connection can cause arching which will disrupt functionality. Loss of any of signals or voltages to the Power Steering control module for even a few seconds will interrupt steering assist and make the car hard to steer. 

In a previous blog I described the  steering loss I encountered due to loss of  voltage to my car's hydraulic pump motor because my positive battery terminal was loose which resulted in intermittent supply to the main steering control module. It is worthwhile to  to check the level of the Hydraulic fluid in the reservoir when you suffer hard of stiff steering. If there is a leak, the hydraulic pump motor cannot produce the necessary pressure resulting in stiff steering. If the fluid is low, refill the reservoir but don't start the engine but get someone to continually turn the steering wheel between the left and right extremes while waiting for all air bubbles to surface. When the appearance of air bubbles  ceases, it would be ok to start the engine. It is also worth your while to   check for DTC's with a scan tool. Should there be a steering error,  deleting often restores steering assist. The LenkhilfeTRW V270 used in the Polo 9N is normally coded as 10110 which can be changed to 10120, 10130 or 10140 in order to incrementally increase the stiffness of the steering. For more Steering codings click here.

TRANSMISSION LIMP MODE

TRANSMISSION LIMP MODE 

During the late 1970's to the early 1980s, the on-board computer made its first appearance, responsible for monitoring and controlling the vehicle's engine. It started out with better fuel economy in mind,  followed by a  electronic capacitive discharge ignition systems (CDI), then electronic points and engine timing were introduced. Soon thereafter it encompassed anti-lock braking (ABS), airbags (SRS), climate control (HVAC), electronic stability control (ESP) and emissions control among several others. Today, virtually every subsystem in your vehicle is controlled by a computer  interfaced with sensors of sorts – including the automatic transmission’s shift timing sequence and line pressure.   The manifold absolute pressure (MAP) sensor and throttle position sensor (TPS), among several other, supplies the engine’s load signals and information which is used by the  Engine Control Unit (ECU) to inform the Transmission Control Unit (TCU) when to manage gear up-shift and down-shift, especially when you’re driving up an incline or inclined toward spirited driving. Since there is so much electronics, there is so much more that can go wrong,  so a  "fail safe" system had to be employed as a safety feature just in case of signal errors  that occur  outside of its expected range.  A feature that would protect the engine / transmission from "runaway" that could cause it to self destruct. 

There is even an Electronic Pressure Control (EPC) valve safety circuit, integrated directly in the transmission hydraulic circuit of all VAG vehicles. When necessary, a part of the gearbox is depressurised to prevent any transmission clutches from closing uncontrolled due to  excessive clutch pressure. This is feature is called the "Emergency Program" aka "Limp Mode"  or "Limp Mode Home".

When your Audi, Volkswagen, Seat or Skoda's  EPC light,  and or the Check engine light,  and or DPF (Diesel Particulate filter) light turns on, your car is likely to go into limp mode, if  it hasn't  already entered into Limp mode. Other than the illuminated light or lights in the instrument panel, and an engine that will not rev more than 2000 revs, neither exceed 30 kph, it gives you absolutely no explanation why it happened.  To make matters worse, there is no definitive list of what causes this elusive limp mode but I have tabulated some of them from personal experience. 

How to fix limp home mode

• Throttle Pedal Sensors (TPS), G79/G185
• Throttle body Position sensors, G187/G188 
• Throttle Valve Control Module, J338
• Engine Component Power Supply Relay, J757
• Intermittent Ignition Coils, N, N128, N158, N163
• Fuel Injectors N30, N31, N32, N33
• Transmission Control Module J217
• Waste-gate Actuator Valve, N75
• Knock Sensor, G61 
• Fuel pressure sensor G247 
• Fuel pressure regulator valve, N276 
• Automatic transmission electronic pressure control (EPC )   solenoid / stuck solenoids
• Transmission solenoid harness

Volkswagen Automatic Transmission Solenoid and Harness kit.

The only way to repair an EPC fault (Limp Mode) or for that matter any fault on any VAG vehicle, is to do a DLC scan to pull the Diagnostic Trouble Codes (DTC) to at least point you in the right direction. One of the most miserable Limp mode experiences ever is a Transmission Limp Mode. They range from a transmission that is low on fluid, to stuck in 2nd gear, to jumping out of gear, to noisy gears selection. But the worst is when  engine antifreeze water from the radiator enters through the corroded ATF cooler lines into the transmission, also allowing the ATF to leak  into the engine coolant, radiator and engine. 

Knowing the Germans, their just had to be a oil cooler for the automatic gearbox integrated somewhere into the radiator. Even though VW claim that ATF is a lifetime fluid", it is only a matter of time before it mixes with antifreeze and water. Anyway, this happens to  the all-in-one radiators  of Volkswagen Jettas, VW Golf 4, Passat B6, Audi A4 Quattro  and I suspect other VAG vehicle which I havn't personally experienced. It also happens to the Mercedes Benz C250, but it's  not an exclusive German car design flaw. It s also prevalent in the Nissan Pathfinder, Fords and Pontiac as well as several Asian vehicles.

Once the oil cooler lines spring a leak inside the plastic radiator, it messes-up the entire system by mixing the anti freeze water mixture with ATF. Yet with all the vehicle on-board electronics there is no visible sign that this cross flow happened nor any electronic detection or indication. Since oil is less dense than water, the gears in the transmission runs in water which causes the  metal gears to rust besides taking  the facings off the clutch plates. Beside the water shorts out the printed circuit board driving the solenoids on the valve body. This type of extensive damage can result in a very expensive transmission replacement if it isn't detected before the damage is done. 

Volkswagen  valve body

An easy way to identify this problem, is to check the ATF dipstick level often, which needs to be between the two notches marking min and max. Much more than that can indicate ATF floating on water. Also verify that the colour of the ATF is translucent red and not brown or black. Bi-annual ATF replacement, though expensive should almost guarantee a trouble free transmission. The logic behind an all-in-one radiator ATF cooler is to heat-up the ATF with the hot radiator water during cold conditions because oil tends to become thick and gel when very cold.  But is may be in your interest to replace your all-in-one ATF cooler with a separate / free standing oil cooler as used in the new cars if you live in a country where it never snows or never experience freezing cold weather.

Universal Aluminum  after market Automotive 13-Roll Transmission Oil Cooler

NEW GENERATION ALL ELECTRIC PHAETON LUXURY SEDAN

New Generation All Electric Phaeton Luxury Sedan

Volkswagen has been delaying the inevitable for way too long by fooling around with emission cheating devices in its EA 189 TDI - 2.0L and 3.0L Diesel Engines, and completely missed the window of opportunity enjoyed by its competitors. To the point that the EPA has placed a halt on all VW diesel engines destined for use in 2016 vehicles.  Meanwhile Toyota sales have topped VW sales for the month of November and outsold Volkswagen for 5th straight month. At this rate Toyota is likely to outsell VW for  December and very likely for the entire year of 2015. 

I'm certain this vexes Volkswagen greatly because Volkswagen has been blowing its own horn as the 'Group of the year for 2014' even though  they are no longer considered among the top fifty companies in Germany. In an attempt to regain its status and as a measure to contain the fallout of the Diesel emissions debacle, the newspapers and magazines have been inundated with Volkswagen Service offers flaunting slogans like.

"Volkswagen Service is proud to introduce Volkswagen Economy Packages".

"Nobody knows Volkswagen better than we do and  nobody's better equipped to service it."

"Let the people who built your car, service and repair your car". 

 "Volkswagen only uses Genuine Parts".

"You  get service of the highest international standard - 100% Volkswagen service".

"Your Volkswagen is Serviced by Volkswagen Certified  Technicians, highly trained and relentlessly dedicated".

The million dollar question is, "Is this enough to make a come back" or "Is it a matter of too little too late". The Diesel Gate Scandal  that cost Volkswagen tens of billions of dollars only caused an enormous surge in EV interest. Today EV prices compare very favourably with petrol and diesel equivalents and electric cars are no longer the preserve of the rich minority. They are now available to anybody who wants a reliable, cheap-to-run car because the days of spending $75 per week to fill up your polluting car will soon be over. 

Considering electric cars have no emissions, and their speed, performance and range have vastly improved. EV's carry no road tax levy and its running costs are as little as 4 cents per mile, a quarter of the average cost for petrol / diesel cars. The Toyota Prius is currently sold in more than 90 countries and its global cumulative sales have passed the  5.2 million units mark  in July 2015. This figure represents 65.4% of the 8 million hybrids sold worldwide by Toyota Motor Company since 1997. Toyota's sales figures for the first three quarters of 2015 stands at 21,210,000,000.00 JPY = 162,256,500.00 EUR or 176,255,100.00 USD.

Volkswagen is on the back foot for not embracing EV's sooner and is scrambling to get their New Generation All Electric Phaeton Luxury Sedan to market by 2017, which is destined to rival both Tesla and Mercedes Benz. The next big question is, "Can VW pull this off sucessfully"?

Initially when Volkswagen's launched their first-generation Phaeton luxury sedan, their objective  was  to prove that they are the world's innovation and engineering leader, and not Mercedes-Benz or Rolls Royce. But the $70,000+ Phaeton was a flop in  North America and was discontinued, yet  it  underpinned the hugely successful Bentley Continental and the Audi A8. From this one can easily see that the Phaeton was probably something very special hence it survived the chopping block,  as all  non essential / unnecessary projects were scrapped because of the ongoing diesel emissions scandal.

A rendered model of what the New Generation all electric Phaeton luxury sedan could look like.

Tesla Signature Series Model X with Tesla's Autopilot autonomous driving system.