Speedometer News: Latest Updates & Info (Solution) | Posts 16+

Hello everyone,

'Over the weekend, I continued my research and came to the following conclusion:'

My cruise control switch doesn't match the 3-position diagram from the Passat wiring schematic, nor does it perfectly match the 4-position diagram from Rudi's first schematic, which should actually be correct for my vehicle. The difference here is a different pin configuration on the switch (mine has only 6 pins, while 'Rudi's' has at least 7). Nevertheless, they are obviously the same internally. My switch apparently belongs to the 1999 model, because it matches the 1999 wiring diagram from 'So wirds gemacht' (a German DIY guide).

Now the only question is which control unit I have. The problem is connecting the 'speed +' signal. According to the wiring diagram for vehicles after 1999, the blue wire is supposed to be in the yellow connector, but in my case, it's providing +12V coming from the control unit. So, either it's the wrong wire, or my control unit is faulty.

@Rudi:
I'd be interested to know: how are T10b, T10d, and T10e described in your initial schematic diagram post?

Hello Thomas,

T10 connector, 10-way, black, for use with the GRA switch.
T10b – Connector, 10-way, black, located on the protective housing on the left side of the engine compartment.
T10 connector, 10-way, brown, located on the protective housing in the engine compartment on the left side (chamber 8 - air conditioning connection).
T10e connector, 10-way, yellow, located on the protective housing on the left-hand side of the engine compartment.

Best regards, Rudi.

Hello Rudi,

Thank you for the prompt reply.

The color coding and connector assignments actually correspond to the wiring diagram for the 1999 model. Only the pins on the engine control unit are different, as the 1999 model has at least 80 pins.

The blue cable in the yellow connector is providing 12V, both with and without the cruise control connected.
This leads me to believe that either my control unit is faulty, or the wiring diagram is not compatible with my vehicle.

Oh man, I'm almost at my limit. Does anyone still need a speed limiter? I have one to give away cheaply.

Regards,
Thomas.

Hello Thomas,
What is the VAG number of your control unit, or how does it report itself (using VAG-COM or a VAG Tester)?

Best regards, Rudi.

Hello,

This weekend, I finally got around to working on my GRA (Ground Relay Assembly) again. As I mentioned, I wanted to try connecting contacts 58 and 66. According to the wiring diagram, contact 58 is not connected in my car, which is what I confirmed. However, I still connected a wire from contact 58 to the control unit and then to contact 66. Of course, it didn't work.

Okay, here's a different question: If I were to take the vehicle to Volkswagen for diagnostics, what could they charge for troubleshooting? Surely, I shouldn't have to pay, say, 1000 euros for something like that, right?

Best regards,
Albrecht.

Hello Albrecht,
Please also provide the part number of your engine control unit (ECU).

Best regards, Rudi.

Hello Rudi,

Here are the data from my engine control unit (ECU):

vag Part No. 028906021GN
component G00SG 1437
softcoding 00002

It would be really great if you could determine which circuit diagram is the correct one based on this information.

By the way, I recently received a tip from the diagnostic tool forum on Yahoo.
According to this, bit 4 of the 6-bit word of the GRA, which is always '1' in my case, is actually...
The position of the '+'-switch is incorrect. Something seems to be stuck.

Regards,
Thomas.

Hello Thomas,
You have mail.

Best regards, Rudi.

Hello, regarding the topic: Something's stuck!

I also had a brand new GRA switch here before. Internally, two wires were connected (incorrectly!).

I also spent a long time searching, then looked confused and exchanged items.
Then everything went as it should!

Just for your information.

Hello KombiBlue,

I will definitely take the steering column apart again and measure the switch very precisely. Thank you for the tip.

Regards,
TWM

Quote:

Hello Albrecht, Please also provide the part number of your engine control unit (ECU). Greetings Rudi

.

Hello everyone,

My tax identification number is 028 906 021 CK.

Gestern habe ich mal meinen Fehlerspeicher augelesen, was bei mir nicht so einfach ist, da ich keinen Laptop zur Verfügung habe! And lo and behold...

Speed limiter, implausible signal.

Unfortunately, I couldn't do a test drive with the PC and I couldn't use the GRA (presumably a diagnostic tool) after clearing the error. In the end, the error was already present when the technicians at VW activated the cruise control .
Nobody could have predicted this, and I'm completely lost.
I think the root cause might be hidden here. I don't have the time to look into it right now; I'll probably get to it at the earliest this weekend.

Does anyone happen to know where this speed limiter is located?
By the way, my speedometer is working perfectly!

Best regards,
Albrecht.

Hello Albrecht,
For the 021CK model, the first schematic diagram excerpt should be used.
The speed limiter should be located on the left side of the transmission.
located above the wave flange.

Here's the translation:

'Also, here are the diagnosis bits for GRA again.'
The table is still missing the first bit (far left), which indicates 'clutch engaged.'
and the second bit indicates 'brake pedal applied'.

Best regards, Rudi.

Hello Rudi,

Thanks for your patience, but I won't have any new information until the weekend!

Greetings.
Albrecht.

Hello,

I connected the PC to the car again today, and here are the results:

Ad group 6, field 3:

000000 Cruise control off.
000001 Cruise control on.
000101 Button pressed.
001001 RES Position
100001 Clutch engaged.
010001 Brake applied.

Ad group 6, field 2:

Bremslichtschalter und Bremspedalschalter springen beim Betätigen der Bremse kurz hintereinander auf 1, Kupplungsschalter ebenfalls. Okay, also also fine.

The "speed sensor - implausible signal" error was also not present in the error memory, so I can rule that out as well.

According to Rudi's plan for GRA error troubleshooting, pin 2 from the right in field 3 should also switch to 1. However, as you can see above, this is not happening in my case. Furthermore, I'm not sure what type of button this should be, as the functions mentioned above seem to cover all switch/button functions?
According to my records (original VW documentation), the image matches the engine code ALE.
The AFN was originally supposed to have only 5 pins (corresponding to the functions).
I'm completely at a loss. Is there a defect in the function of my control unit? Or is it really the case that there are so many different control units in essentially identical cars that such errors occur by chance?
Michael II always had a good understanding of internal matters at Volkswagen; perhaps he could comment on this.
I don't know what else I should do/check, since everything seems to be fine, but the cruise control isn't working .
I would appreciate any comments and suggestions.

Best regards,
Albrecht.

Hello Albrecht,

Either your GRA switch is faulty (mine exhibited the same behavior after a short time), or you have forgotten to connect a pin.
As long as the second bit from the right is not set, GRA functionality will not work.
Tip: If your switch is broken, do what I did and connect the pin that works in the "on" position of the switch to the corresponding pin (the one that never reaches "1" in your setup).
The only drawback is that you can't turn off the GRA (Graphic Rendering Accelerator) by simply tapping the "off" button; you have to either completely slide the switch to the "off" position or tap the brake.
So, you see, there's no real problem.

You can also simply exchange your defective switch (provided you haven't forgotten any wires or if there isn't a loose connection in the connectors to the control unit).

By the way, you're the third known TDI driver with this problem, and I'm curious to see if my suspicion is confirmed in your case.

Best regards, Rainer.

Hello Rainer,

The switch isn't defective on my end. I've already tried several other switches (that work in other vehicles), but they don't work either!
The more I think about it, the more I believe that my engine control unit doesn't belong in my car!
As far as I can remember, your GRA switch has 5 cables, but mine only has 4.
According to VW documentation, in group 06, field 3, older GRA/control units with 4 wires have 5 pins, while newer units with 5 wires have 6 pins.
So, I'm not sure where to get the missing pin that isn't jumping to position 1, since all the switches and button functions are working correctly on my unit. The problem is that there's a cable missing that connects to terminal 58 on the new GRA switches/control units (as mentioned above). However, terminal 58 is not connected on my control unit. I've already tried connecting terminal 66 (which is "On") to terminal 58.
Rudi already mentioned that my tax identification number should match the wiring diagram, but according to the (standard, pre-installed) wiring in the vehicle, it's not the correct one.
I'm repeating myself: I bought the original VW retrofit kit for my car and engine code (MKB). The wiring is pre-installed from the factory. So, it's installed, connected, activated, and ready to go!

I would love to just leave the car at VW and let them deal with it, but that would be too expensive .

The only thing that comes to mind now is that when I tried to change the setting from Contact 66 to 58, the problem was a speed limiter issue in the memory, which is why it didn't work. So, I'll try that again.

Best regards,
Albrecht.