Cruise Control Not Working After Engine Swap

[logique]

I just completed an engine swap in a 96 passat VR6 from a 96 Passat TDI. Everything is working as expected, however I have no cruise control. Prior to swapping the engine, the TDI's cruise control worked perfectly.
Besides the engine, I swapped the ECU, wiring harness and pedal cluster. The brake and clutch pedal switches appear to function properly. In VCDS, measuring block 006, I get what you see in the screen shot when I push on the clutch and brake pedals. When I let go, I get all zeros which I think is normal. When I turn on the CC, I get nothing, no cruise present and all zeros. I also tried this while driving the car and the speed field was accurate. I tried the two switches from both cars and they both give the same result. Like I said, this switch was working fine in the TDI.

I also deactivated and reactivated the CC in the ECU using the "Login - 11" and codes 16167 and 11463. I was able to verify this by looking at the component code in this screen shot. The letter G before "70SG" disappeared upon deactivation and reappeared when reactivated.

Any ideas what I may have overlooked and what I could test?

 

[CasaEd]

In group 006 the clutch and brake switches are shown as being activated, i.e both pedals pressed, is this correct ?

 

[logique]

Yes, the screen shot shows both pedals pressed.

 

[CasaEd]

Ok, I remembered this when I went out shopping. When I was running GM & GC firmware in my ECU I could never get the cruise control to work.
At the moment I'm using JB firmware and it works with just one brake switch, ok not ideal because if you press the clutch when driving the
engine revs up high, so you either have to dab the brake pedal or turn the cruise off first. I'm not too bothered by this because soon I'm
updating to a OBD flashable ECU, so if you have a socketed ECU you could reflash, but JB firmware is for WG turbo, not sure what you are running, but I think GQ is also WG turbo ?

 

[logique]

I have the original turbo which I think is WG, but I'm not sure I want to reflash. Isn't JB for a Jetta? Like I said everything was working fine prior to the swap with the same ECU and wiring. Also, everything else is running great on the car (or at least, the same as before).

 

[turbodieseldyke]

Correct, JB is Jetta. I believe Passats had BK (96), GQ (96 updated), and FA (97)

 

[CasaEd]

Yes JB is Jetta, but like I said I had no luck with any G* software, I spent hours checking the wiring etc, everything showed up correctly in vag com
cruise control switch worked as it should, had a speed signal when driving, but could never get it working until a changed to JB firmware. My ECU is socketed and I have a programmer so easy for me to try. By the way if your ECU is socketed all firmware before G* will not work, I've tried them all
in my quest for a working cruise control. My original black cased ECU worked too, but I wanted to be able to tune the car myself so I swapped out
the original ECU for a silver cased one.

 

[logique]

How do I know if my ECU is socketed and why would it stop working after a simple engine swap? My ECU has a silver case.

 

[Steve Addy]

How much of the original VR6 wiring did you remove and replace with the TDI wiring?

Specifically which harnesses did you swap in from the TDI?

Steve

 

[logique]

Definitely the TDI main engine harness. I think that's the only one. I kept the VR6 cooling fan control switch relay module along with the harness and radiator and VR6 lights harness. I removed the air conditioning because it didn't work and I kept the TDI instrument cluster. And of course I kept the VR6 ABS controller and harness.

 

[Steve Addy]

Did you eliminate the VR6 cruise components and rewire the column switch to go with the TDI engine wiring harness? The VR6 uses a cruise module and has different wiring for cruise than the TDI. That might be part of your problem.

I doubt the ABS is causing any problems, that system is pretty much isolated from the rest.

Steve

 

[logique]

Yes I removed the VR6 accelerator and brake pedals along with the throttle cable, vacuum lines and wiring. I replaced everything with the TDI components and the clutch and brake switches. It's all electronic. I believe the car wouldn't be running if I didn't do this I think. And the car runs great.
Yes, the ABS is pretty much isolated from everything else.

 

[Steve Addy]

Ok, and sounds great, but what did you do to the cruise stalk and the old wiring and the old cruise module? Also, was the VR6 originally MT or AT?

I'm only asking this because the tdi and VR6 Passat cars have differences beyond just the F, G1 and G2 harnesses, and obviously something isn't working right or you would have cruise. Since the TDI car had a functional cruise and the new converted one doesn't, it's something different between the two vehicles that's interfering, or something that's not hooked up properly post-conversion.

I did this conversion on a 1990 Passat 16v AT car and it took me a while to perfect the wiring components, but I was also using a Mk3 front wiring harness which needed a lot of sorting to make the harness appropriate to the car, but my cruise worked when it was done.

Steve

 

[logique]

What does MT and AT mean? I was under the impression that the VR6 and TDI cruise control were totally different. I kept the accelerator potentiometer from the TDI and the pedal switches. As for the cruise stalk, I tried both. They are basically the same anyway. I will check the wiring again from the cruise stalk and the potentiometer.

 

[BigAndy]

The wiring from the cruise control stalk goes directly to the fuse box panel in a TDI -- from there to the ECU - the gas version plugs into a different spot on that fuse block I believe. It's a four wire harness.

 

[logique]

On mine, from the cruise control stalk, the four wire plug goes to a four wire harness that, in turn, connects directly to the engine harness. The picture shows the connection to the engine harness. I had to move the fuse panel to take this.

 

[Steve Addy]

There are differences in overall wiring between AT (auto trans) and MT (manual trans) for the VR6 cars. In other words, the differences between gas and diesel are not exclusive to harnesses F, G1 and G2. The AC system is different, cruise is different, something the cruise requires is missing if it's not working and you've eliminated the stalk.

If you've completely removed the VR6 cruise control and the wiring that went with it that's part of it, same with the AT wiring harness and TCU if it was an AT car. But again there's something that the ECU needs that's not there, even if it is running properly. The Bentley might be good to look at if you have it.

Did you try and drive the car with VCDS connected to see what was reported in measuring blocks when you activated the cruise? One of the big things that I recall when cruise isn't working is a problem with VSS.

 

[BigAndy]

Troubleshoot the wiring with this link: https://www.clubgti.com/forums/inde...ro-fit-cruise-control-to-mk3-golf-tdi.241644/

 

[BigAndy]

I wonder if the wiring from the stalk is matching the wiring to the ecu?? That's why I posted the link so it might help identify.

 

[logique]

Steve Addy, both cars have manual transmissions. I tried driving the car with VCDS and I get the proper speed reading in the first field but no cruise when I activate the CC.
BigAndy, from the link you gave me, I should get voltage on the black wire. also from this link: https://forums.tdiclub.com/index.php?threads/cruise-control-how-to-ahu.193855/ that wire should come from pin 66 on the ECU plug. I verified this by checking continuity from pin 66 all the way where the stalk plugs into the 4 pin harness, I get 0 ohms, so it's the correct wire. If I turn on the ignition, I think I should be getting voltage between pin 17 and 66 but I get nothing. I think my problem is not getting voltage but I'm not sure if I'm measuring it correctly.

 

[Steve Addy]

Since both were MT it's simplified and the cruise stalks are the same gas and diesel so that's not the issue. The pin 66 wire is as you indicate, the pin 17 wire is the for the (F36) clutch vacuum vent valve, wire position #2, position #1 should be br/bl to ground 220 in engine compartment wiring harness, have you verified you have good ground here?

This will be same ground for the (F47) brake vacuum vent valve too, same color br/bl, position 2 in the connector.

Steve

 

[logique]

The car is getting a safety check today in order to get plated. I will verify tomorrow. Thanks.

 

[logique]

Just to be clear, here is what I'm doing. I've verified the following for continuity.
On the plug that connects directly to the stalk, see picture, the positions are numbered 1 to 4.

and on the big plug that connects to the ECU, there are 68 connections:

ECU plug Stalk plug
pin 1 --> position 1 (ground, matches many other pins)
pin 33 --> position 2
pin 34 --> position 3
pin 66 --> position 4

If I turn on the ignition, I set the multimeter to voltage, put one lead on pin 66 and the other on 33, I get zero. If I put one lead on pin 66 and the other one on the negative battery terminal, I get zero. Should I be reading 12V here? If so, where does it get it's power?
I checked all the ground points and everything seems to be good.

 

[Steve Addy]

First and foremost I'm going to say I'm not sure what you'd expect to see on those connections. Personally, I think the best you can do with these is test for continuity because you're not trying to activate the cruise (car isn't running) and hence nothing is being set. That's especially the case with the connector to the ECU unplugged from it.

I will fire up my VCDS and see what happens when look at the cruise and when I set it on the highway. It will be later tonight when I get back with the results however.

Steve

 

[logique]

I've done further testing after plugging everything back ( except the cruise switch). When I jump wires 1 and 4 (pins 1 and 66) simulating an ON switch and I apply power to it, I get a 1.0 at "Cruise present" and a 000001 at the third field in VCDS. Here is what I'm doing:

I guess this further proves that I'm not getting any power at the switch. I've tested the switch for continuity and it seems to work. I just don't know where it's supposed to get it's power. I have 2 switches from the 2 cars and they both behave the same way.

 

[BigAndy]

From the link I sent you earlier in this thread:

5) The black wire is the 12+ and should be live when the ignition is on, this should be connected to one side of the on/off switch.

 

[BigAndy]

More diagrams to help http://www.a2resource.com/electrical/CE2.html Cruise black +12 runs through fuse 14 - D/11 on the list.

 

[Steve Addy]

More diagrams to help http://www.a2resource.com/electrical/CE2.html Cruise black +12 runs through fuse 14 - D/11 on the list.

I'm not sure that's true in the case of the TDI since there's no cruise module. IIRC the connection with the switch is exclusively to the ECU via ECU pins 17, 20, 34 and 35. Since there's no module there's no connection at harness D/11.

I had originally thought about D/11 and the other at W/01 but then dismissed them because it was in my recollection that those did not apply to TDI cars. And I just looked at a spare B4 front engine harness assembly (F, G1, G2) and the connection to the cruise stalk does not connect anywhere else except back to the ECU. The A2resource information is invaluable, I use it often, but it is not exclusively TDI related and in fact there are significant deviations for the TDI cars. Overall it's very reliable but must be taken with a grain of salt and with the aid of the Bentley for the model in question.

It's unusual to have two switches fail, but not unheard of, but since they worked previously I suspect the fault is elsewhere. Have we determined that the brake / clutch pedal switches are installed properly?

I am sorry I've not gotten VCDS data for cruise activation yet, it's been very busy week for me and it's not over yet. I will try to get it today while I'm on the road.

Steve

 

[logique]

Thanks for your help guys.

From the link I sent you earlier in this thread:

5) The black wire is the 12+ and should be live when the ignition is on, this should be connected to one side of the on/off switch.

That's how I figured there should be power at the black wire in the stalk switch, but there isn't. Also, I checked fuse 14.

And I just looked at a spare B4 front engine harness assembly (F, G1, G2) and the connection to the cruise stalk does not connect anywhere else except back to the ECU.

That's what I've observed too.

Have we determined that the brake / clutch pedal switches are installed properly?

I'm pretty sure the brake/clutch pedal switches are installed correctly. See first post for the VCDS screen shots.

I've taken one of the switch stalks apart and I still can't see how power is supposed to get to the black wire from there. It's all enclosed in plastic. After dismantling and cleaning it, I checked for continuity everywhere I could see metallic parts.

 

[BigAndy]

If you aren't getting power on the black wire - you don't have a problem with the stalk. The black wire should have 12v when the ignition is on. If you don't, you need to look downstream. Steve is right on one hand with there being no control module, but this black wire seems to deliver power to more than just cruise. I don't have my Bentley manual handy but I think you need to find out why you don't get power there first. To restate this - if you aren't getting power from the black wire which comes from the ECU, your problem lies there or further downstream, not at the switch.