Right rear door control module no signal/communication

[neo1111]

Hi,

I have an Audi A5 B8 8TA Sportback 2.0TDI CGLC Manual. I have the below problem.
No part replaced and everything worked as intended. The signaling lights did not come on once I locked the car(plus the red led on driver side indicating a fault). Checked every door and the rear right side did not locked. Did a OBDeleven scan of the car[photos attached].
- Comfort System central control module Please read DTC static 01330[Keyless System]
- Driver Door: Right rear door control module no signal/communication 01334 static
- Conform System: Right rear door control module no signal/communication 01334 static
- Passenger Door: Right rear door control module no signal/communication 01334 static

No door open in the cluster dashboard. The faults are unclearable.

Then checked:
- fuses and are ok[from the passenger, driver plus the right side boot comportment where the comfort calculator is]
- dismantled the driver side door cover and checked the cables-visually, as far as I could(plus cleaned with electrical contacts spray)
- repeated the process for the rear right door
- swapped the door control module between back doors-still the same

The odd thing is that for a short while, the window motor button works from the back and driver side, then it does not anymore(seems like a capacitor problem somewhere). // once I disconnect the rear right door cable and plug it back in

Getting back.
- replaced the door latch entirely(microswitches etc.) and I have the same status.
- plugged the rear door pillar cable connector out ->did a rescan-> still the same status-not seen at all. So the door control module seems not to be the culprit. My guess goes on the central comfort calculator in the back(trunk right side).

If I check individually the components, it does not see the rear door at all(it did initially as far as I remember), but if I login again in the app, it sees the right rear door(hardware and software values).

My next guess is that the comfort calculator on the back(right side trunk) might be faulty-some component in the circuit board which handles that specific door.

I intend to buy a donor comfort control module and reprogram it using OBDeleven with the same long coding as the current one.
See what it is the status afterwards and consider other options at that point.

Any ideas are more than welcomed.

[Smac770]

Does the driver sit on the left or the right in this vehicle?

At the 20-pin plug for the right rear door control module (J389), there's 4 pins you care about validating. Reading 12v from pin 18 to pin 20 and from pin 19 to pin 20. And then reading some kind of voltage activity on pin 10 to pin 20. Pin 18 and 19 are 12v from the fuses (B8.5 gets rid of one of them, but you don't say if you're B8.0 or B8.5). Pin 20 is ground. Pin 10 is LIN bus from the front door control module on that side of the car. If you swapped control modules left<>right and no change in error codes, then you more likely have a wire issue than a control module issue.

[neo1111]

Does the driver sit on the left or the right in this vehicle?

At the 20-pin plug for the right rear door control module (J389), there's 4 pins you care about validating. Reading 12v from pin 18 to pin 20 and from pin 19 to pin 20. And then reading some kind of voltage activity on pin 10 to pin 20. Pin 18 and 19 are 12v from the fuses (B8.5 gets rid of one of them, but you don't say if you're B8.0 or B8.5). Pin 20 is ground. Pin 10 is LIN bus from the front door control module on that side of the car. If you swapped control modules left<>right and no change in error codes, then you more likely have a wire issue than a control module issue.

Seems like a wire issue to me as well. Have not measured any voltage values on the wires yet-just visually inspection(as much as I could). If I disassemble the connector to the pillar, I am not sure I will be able to put it back as it is. Now I also have some short-circuit for the door twitter, yet it does work-so wire problem it seems(intermittent).
I have added some screenshots with I have checked again: the rear right door is 'seen' once I unplug the OBDeleven from the car socket-or disconnect(in the app): not sure if this remained there after previous checks(db or app cache whatsoever).
Pressed the 'child lock' from the driver side(left side) and then an error on the cluster appeared-then it disappeared: it works as intended on the left side. Sometimes the window button works on the right side as well-sometimes it does not: the car was stationary.

I wonder if I should check also the pins on the door pillar-where the door cable connector gets plugged in-yet I do not want to cause a short circuit somewhere else due to my incapacity. I would consider buying of a new wire harness(door connector) and cut the cables and saw them back in: as I believe that the short might actually under the plastic protection. I will get back with updates once I manage to check again-probably during this weekend.
Thanks a lot for your response(and all of you which are checking this) and sorry if I make some wrong assumptions and anything related. Most probably I should go to a repair shot and have them check, yet I wanted to have myself a look prior of this.

[Smac770]

The pins are different at the harness junction to the chassis. I was talking about the 20-pin plug on the door harness to the control module itself, behind the trim panel.

As you see, getting a meter on the pins on the chassis side socket is not a simple task unless you have a proper meter probes pigtail set.

DTCs will get set if you disconnect things with power on. You just clear DTCs and see what comes back after any kind of test operations.

I'd get the door panel off and start testing wires in the door harness. Maybe there's a flaky connection along the way, or maybe it's a flaky splice there in the door harness. Hard to speculate until hands on has occurred.

The door to chassis plug isn't that bad. I use a small flathead screwdriver to knock the release up until it frees, then the plug just comes right off.

[neo1111]

The pins are different at the harness junction to the chassis. I was talking about the 20-pin plug on the door harness to the control module itself, behind the trim panel.

As you see, getting a meter on the pins on the chassis side socket is not a simple task unless you have a proper meter probes pigtail set.

DTCs will get set if you disconnect things with power on. You just clear DTCs and see what comes back after any kind of test operations.

I'd get the door panel off and start testing wires in the door harness. Maybe there's a flaky connection along the way, or maybe it's a flaky splice there in the door harness. Hard to speculate until hands on has occurred.

The door to chassis plug isn't that bad. I use a small flathead screwdriver to knock the release up until it frees, then the plug just comes right off.

Thanks for the reply. I hope to check it again during this weekend. I will get back with updates once reviewed.

[neo1111]

I will seek professional help further as I am unable to get this fixed. Since this is the rear back door, it is not of a big concern yet(able to manually lock the door). Either way, as soon as I have the fix in place, I will update this post for future references.

[Lonnie]

Hello, I have the exact same problem with my 2010 Audi a5. Can you update the post and tell us if you found the solution for your Audi? Maybe it will work for me also

[neo1111]

Hello, I have the exact same problem with my 2010 Audi a5. Can you update the post and tell us if you found the solution for your Audi? Maybe it will work for me also

Hi,

Sorry-still faulted. I only managed to discuss via phone with a car electrician(explained the problem and what has been done currently). Swapped the rear door control modules in between, and the faulty door control module works as intended on the left door side: the problem is still the same on the right door(even with the rear left door control module). So this(rear door control module) is not actually faulted.
Was not able to check the above mentioned PINs(do not have the wiring diagram to know what exactly to measure).

So the door latch(already replaced) + rear door control module are not at fault. It might be the cable/connector in the rear right side door, or some cable/connector in the driver side door(or control module which communicates with the rear one) , or maybe some fault in the comfort calculator in the trunk(right side(main comfort calculator, yet this is just an assumption).
What I managed to investigate online(based on the error codes and onto similar behavior overall): the door harness(faulted door + checkings on the driver side door harness/cable) was replaced entirely and the problem was still present. The problem was that some connector to the fuse(which operates that door control module) which was bad-or something like this, if I remember correctly. Might be the case here as well.

I will have to make a scheduling in some repair shop-if possible on Saturdays, yet most of them are closed.. So I'll have to check this during the normal business hours, more than sure.

Either way, f you manage to identify the fault sooner than me, kindly let us all know(for future similar cases).

[Lonnie]

Hi,

Sorry-still faulted. I only managed to discuss via phone with a car electrician(explained the problem and what has been done currently). Swapped the rear door control modules in between, and the faulty door control module works as intended on the left door side: the problem is still the same on the right door(even with the rear left door control module). So this(rear door control module) is not actually faulted.
Was not able to check the above mentioned PINs(do not have the wiring diagram to know what exactly to measure).

So the door latch(already replaced) + rear door control module are not at fault. It might be the cable/connector in the rear right side door, or some cable/connector in the driver side door(or control module which communicates with the rear one) , or maybe some fault in the comfort calculator in the trunk(right side(main comfort calculator, yet this is just an assumption).

I will have to make a scheduling in some repair shop-if possible on Saturdays, yet most of them are closed.. So I'll have to check this during the normal business hours, more than sure.

So, if you manage to identify the fault sooner than me, kindly let us all know(for future similar cases).

Thank you very much for the update. I will try to swap the door modules like you did and see if it changes anything for me. Also if I will solve this problem I will for sure post here and explain what I did.