Electrical Malfunction

[astew]

Hello,

Sometimes while driving and coming to a stop I will recieve electrical malfunction error on the dash, and automatic start stop is disabled. The alternator also appears to not be charging the battery 11.5v when the error is present. I can fix this by clearing the code with ODB 11 and the alternator continues to charge the battery 13.5V under load. I was wondering if anyone knows what this issue could be.

Thanks

[Smac770]

What is the error from the CAN Gateway, address 19?

[astew]

Fault Codes are U105200 and C11CB01.

[Smac770]

Those codes alone mean nothing. Are we to presume the U1052 is suppose to be no comms to the voltage regulator? That would be relevant to your random alternator output issue. Getting to the plug to the VR on the V6 is not nearly as easy as on the I4. But that would seem to be your starting point. An issue in the wiring from the splice point on the LIN bus line from the J533 to the J367 BDM on the battery and the VR on the alternator. Or could be a failing VR itself.

There is a connection point in the wiring to the VR, "TMR", if you remove the right wheel well liner, it apparently is in the front side with several other connectors. Worth disconnecting and reconnecting the plug to the VR and that connection plug in case it's a poor connection.

[astew]

Okay I will check it out. I also was driving today and noticed voltage drop when pressing on the throttle, down to 12.7v and right when I left off it jumps to 14.9v. Any amount of throttle will make it drop. Turning on the ac and radio don't seem to do anything.

[astew]

I replaced the alternator with a used one off of ebay for the problem to only appear again after a few weeks. I'm not even sure the old one was broken or not. I was unable to find the wire lead coming off the voltage regulator. The wire is purple with a blue stripe and I open cut several points near the wheel splice point and did not see the same color wire. Let me know if I could you know a way to diagnose with obd 11.

[crhh95]

I’m having the same thing with mine. Not sure what’s going on, but it seems to fluctuate


Sent from my iPhone using Audizine Forum

[Smac770]

forgot this was B9 forum.

The 2-pin connection point TMR is where the alternator voltage regulator LIN line (violet/blue on alternator side; violet/white on the vehicle side, such as at the battery negative post) and the starter term 50 control line (red/black on both sides) pass through. TMR should be behind the passenger side wheel well liner directly under the headlamp plug.

[astew]

Yeah, you are correct I found the tmr. The connection point there is good, however, the connection point to the J533 (under center rear seat) has no continuity and will likely have to replace the wire. I have unplugged pin 16 the violet w/ white stripe wire and the alternator is charging the battery! Now I have and error in obd 11 for the battery control module on the battery, not sure if I can run the car without it until I get the wire and terminal pins.

[Smac770]

Ok, so connection point TMR.

You say you have the violet/blue wire on one side, and that tests good to the wire on the plug at the voltage regulator on the alternator?

But the violet/white wire on the other side of TMR, that fails to test continuity to the violet/white wire pin on the J533? Unfortunately, the wiring schematic doesn't document another other pass-through plugs like TMR on the way to the J533 for one to investigate. The break could be anywhere from the TMR to the J533.

The violet/while wire on J533 plug T54 pin 16 is a LIN bus, with the J367 battery diagnostic manager and the alternator voltage regulator. By removing the pin at that location, you've cut the J533 off from both the J367 and the VR. I would have depinned the violet/white in the TMR plug instead. This would have kept the J533 communication to the J367 in tact.

[astew]

Yeah there is a connection with a connector between the tmr. It has a violet/blue wire going to the alternator's voltage regulator, this tested good. For the J533 I ran a jumper from the tmr violet/white wire to the other side at the J553 plug, with no continuity on my meter.

Good idea on depinning more downstream. I wonder if it is safe to run it like this or if it would burn out the alternator/regulator or possibly overcharge the battery, I am not driving the car atm just wondering.

[astew]

So I added a temp jumper from the tmr connection point purple/white to the J533 pin 16 and the fault for the generator is now gone, however, I have no comms to the battery control module now. The voltage at the start goes from 14.2 for around 5 seconds and then drops to 13.8. I wonder if it has comms to the battery control for a few seconds then faults out.

When I remove the connection pin 16 and connect it to nothing the error for generator communication appears again however the alternator is still running at 13.8v at the start and I have comms with the battery module. Not sure what's going on. No warranty anymore :s

[Smac770]

As mentioned, you should leave the wire at the J533 as is and just splice in the new wire. That way the J367 stays connected, and now there's a working route to the VR. It's a T config, not a daisy chain.

[astew]

Okay, I will try that. I did have it wired that way, but I realized I was viewing the codes in obd 11 wrong and switched it back.

After I replaced the wire the code goes from static to intermittent and I believe these codes are cleared after a certain amount of start cycles.

Also, I did find some tape on the wire way that don't look factory so someone was doing repairs before me. I don't think this issue is from the factory.

[Bmoreill3]

where do i find the wiring diagram 2021 rs5?

- - - Updated - - -

where do i find the wiring diagram 2021 rs5?