Hi, hope maybe someone can help me disagnose this.

I recently had to get my intrument cluster resoldered after gettting dozens if spurious error codes and an engine fault - a common fault as I understand it.

This all now seems to be resolved, but I'm left with a single error B2086 when I run the Driver Door Control Unit test in Forscan.

Everything seems to be working fine, and I wouldn't have even found this fault if it wasn't for the IC issue. I'm tempted to leave it be, but it is annoying me that I don't know the cause.

The error only happens when I test with the child-lock switch on the drivers door control panel disabled. If I enable the child lock (illuminated) the test then passes without any error.

As I say, the child locks all seem to be working ok, as is everything else.

I've tried replacing the drivers door control/switch panel with a cheap used one off ebay, and I've also tried running the test with both of the rear window switches disconnected, but none of this has made any difference.

Any thoughts or ideas much apprecated!

I'd like to check the door control unit wiring, as per the disagnostic message, but I don't know where this is located

 

Tim

 

===================

B2086 - Rear Window Lockout Indicator Short Circuit to Battery.

Diagnostic Trouble Code details

Rear Window Lockout Indicator Short Circuit to Battery.

Carefully check the wiring between the door control unit and the power window switch assembly.

=======================
 

5 hours ago, TimRob said:

The error only happens when I test with the child-lock switch on the drivers door control panel disabled. If I enable the child lock (illuminated) the test then passes without any error.

You will always get that error when the child lock button is disabled. The BCM and DDM aren't able to complete the test as the window circuit is grounded.

It's not a fault provided the error is not there when the rear windows  are active.

3 hours ago, unofix said:

You will always get that error when the child lock button is disabled. The BCM and DDM aren't able to complete the test as the window circuit is grounded.

It's not a fault provided the error is not there when the rear windows  are active.

Ah, ok, thanks for the help!

Something I didn't mention is that I've been keeping an eye on the error codes since I had the IC repaired, and I had this little lot come up a couple of weeks ago.

I ignored/cleared it, assuming it was related to the same door module fault...

 

 

===PDM DTC U0202-20===
Code: U0202 - Lost Communication With Door Control Module D

Status: 
 - Previously Set DTC - Not Present at Time of Request
 - Malfunction Indicator Lamp is Off for this DTC

Module: Passengers Door Control Unit
===END PDM===

===PDM DTC U1900-20===
Code: U1900 - CAN communication bus fault

Status: 
 - Previously Set DTC - Not Present at Time of Request
 - Malfunction Indicator Lamp is Off for this DTC

Module: Passengers Door Control Unit

Diagnostic Trouble Code details

CAN Communication Bus Fault - Receive Error

Note:

DTCs that start with 'U' are faults which occur during module-to-module communication.

Modules should never be replaced based only on a 'U' code. These codes do not always indicate a problem, and can be caused by normal diagnostic functions, carried out on the vehicle.

===END PDM===

===DFDM DTC C198F-20===
Code: C198F - Lost Communication with Switch Pack

Status: 
 - Previously Set DTC - Not Present at Time of Request
 - Malfunction Indicator Lamp is Off for this DTC

Module: Driver Door Control Unit
===END DFDM===

===DFDM DTC U0201-20===
Code: U0201 - Lost Communication With Door Control Module C

Status: 
 - Previously Set DTC - Not Present at Time of Request
 - Malfunction Indicator Lamp is Off for this DTC

Module: Driver Door Control Unit
===END DFDM===
 

2 hours ago, TimRob said:

Modules should never be replaced based only on a 'U' code. These codes do not always indicate a problem, and can be caused by normal diagnostic functions, carried out on the vehicle.

This is very true. U codes often caused by low battery voltage, or just things being disconnected and then reconnected.

11 hours ago, unofix said:

This is very true. U codes often caused by low battery voltage, or just things being disconnected and then reconnected.

Actually, I have noticed the voltage has been down a bit of late, been thinking of replacing the battery but thought I'd sort out this door error first in case there was some power drain going on.