Cause
Broken wire in the door harness boot
A conductor fractured inside the rubber concertina carrying wiring from the body into a door — the most recognisable fault on any body network, and the first thing to suspect on anything door-related.
The mechanism is simple fatigue. Every circuit reaching a door — the window motor, the lock, the mirror, the speaker, the switches, the courtesy lamp, the door switch — passes through that boot, and the whole bundle flexes each time the door opens. Over a vehicle's life that is tens of thousands of cycles, and copper strands work-harden and break. The break is usually inside the insulation, so the wire looks perfect and only fails a continuity test when it is flexed.
The diagnostic signature is unmistakable once it is known: the fault changes as the door is moved. Something that works with the door open and stops when it closes, or comes and goes as the door is swung, is this. That correlation is worth more than any measurement, and it is available to the owner for free.
Which circuits fail says something too. One broken conductor gives one dead function; several unrelated door functions failing together points at the same bundle rather than at several parts, and is the strong version of the same evidence.
Repair means opening the boot and splicing, and the work is worth doing properly: a bundle that has broken one strand has flexed every other strand the same number of times, so soldered and sleeved repairs with slack left in the loop outlast a quick twist-and-tape by years. Sliding doors and tailgates suffer far worse, since their looms travel further.
Typically a moderate job.
Codes this can cause (69)
Codes where this is a likely explanation first, rather than merely a possible one.
- U0010 Medium Speed CAN Communication Bus Likely for this code Moderate
- U0012 Medium Speed CAN Communication Bus (+) Open Likely for this code Moderate
- U0015 Medium Speed CAN Communication Bus (-) Open Likely for this code Moderate
- U0019 Low Speed CAN Communication Bus Likely for this code Moderate
- U0021 Low Speed CAN Communication Bus (+) Open Likely for this code Moderate
- U0024 Low Speed CAN Communication Bus (-) Open Likely for this code Moderate
- U0143 Lost Communication With Body Control Module C Likely for this code Moderate
- U0144 Lost Communication With Body Control Module D Likely for this code Moderate
- U0183 Lost Communication With Lighting Control Module — Rear A Likely for this code High
- U0199 Lost Communication With Door Control Module A Likely for this code Moderate
- U0200 Lost Communication With Door Control Module B Likely for this code Low
- U0201 Lost Communication With Door Control Module C Likely for this code Low
- U0202 Lost Communication With Door Control Module D Likely for this code Low
- U0203 Lost Communication With Door Control Module E Likely for this code Low
- U0204 Lost Communication With Door Control Module F Likely for this code Low
- U0206 Lost Communication With Folding Top Control Module Likely for this code Moderate
- U0213 Lost Communication With Mirror Control Module A Likely for this code Low
- U0215 Lost Communication With Door Switch A Likely for this code Low
- U0216 Lost Communication With Door Switch B Likely for this code Low
- U0219 Lost Communication With Door Switch E Likely for this code Low
- U0222 Lost Communication With Door Window Motor A Likely for this code Low
- U0223 Lost Communication With Door Window Motor B Likely for this code Low
- U0226 Lost Communication With Door Window Motor E Likely for this code Low
- U0227 Lost Communication With Door Window Motor F Likely for this code Low
- U0230 Lost Communication With Rear Gate Module Likely for this code Low
Information, not instruction
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