PD TDI Without ASR?

Was there any PD TDI car using an EDC16 ECU with no ASR or ESP from the factory? Euro or NA.

I'm having a heck of time trying to figure this one out.

(that's a lot of acronyms for one question...)

My BEW originally had no ASR or ESP.

turbocharged798 said:

My BEW originally had no ASR or ESP.

Click to expand...

Ah hah! Do you perchance have access to your car's Bentley wiring diagrams for the ABS module? Specifically looking for whether pins 13 or 29 of the ABS module are used for anything.

To clarify, I want to know where the CAN bus low pin on the ABS controller goes to on the ECU. It took me a bunch of hunting through a few wiring diagrams to follow that circuit. It goes through the instrument cluster before going to the ECU. On a BHW, it goes to T94/66, but I think that's specifically for cars with ASR. On cars without ASR, I think it's supposed to go to a different pin, and I'd like to know which one.

Ok so looking at the wiring diagrams, the ABS module connects directly to the ECU via T94/66 and T94/89. Those are can low and can high respectively. Bentley isn't clear if these are the same can wires that go to the cluster. It just has a J... next to it. Seems they got lazy and said screw it.

It's all the same for standard ABS and ASR/ESP cars.

66 and 89? On the Passat BHW (with ASR), it's 66 (low) and 69 (high)... I wonder if that's the difference. Hmm...

This is starting to make sense. Maybe I can figure out this "Missing message from ABS controller" after all. I got Malone to code out the error, but the underlying symptoms still exist. My dash beeps loudly at me every once in a while when I start the engine (with no apparent warning light), and there's been some occasional minor ABS actuation issues.

What ECU are you using?

North American B5.5 Passats had EDC16, same as BEW. The European models still used EDC15.

I double checked and my Bentley says pin 89 high.

Thanks! I'm starting to think the way the ECU knows which features are installed is by which pin the modules communicate on. For example, on an AWM 1.8T, if ASR is installed, CAN low from the ABS module goes to the instrument cluster and then pin 58 of the ECU. If ASR isn't installed, it goes straight to pin 74 of the exact same ECU. I've seen similar things with other modules. There really isn't much that can be communicated over a couple of un-shielded copper wires running through a car, anyways (except maybe "I exist!"), so this would make sense.

In any case, the ABS CAN low on my A4 definitely doesn't go to the right place right now, and it looks like CAN high will have to change pin as well. I think getting those two wires sorted would help resolve the ABS controller issues once and for all.

I upgraded all our mk4s with ASR/EDL and when I did everything worked straight off without issues. But this is the A4 chassis, yours might be different.