Network
generic / SAE
U020A
Lost Communication With Moveable Roof Control Module B
ECU lost communication with moveable roof control module B (panoramic sunroof, hardtop). A communication loss with this module breaks any function relying on its data — diagnostic tools may show 'no response' and dependent modules can fall into limp mode.
SystemNetwork
Typegeneric / SAE
GroupU0
Range / number2 / 0A
Possible causes
- Module unpowered high
- Gateway module routing CAN messages incorrectly low
- CAN terminating resistor (120 Ω) drifted out of spec low
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
Inspection / repair
- Difficulty: medium
- DIY: shop recommended
- Estimated cost: 100–1200 €
- Estimated time: 0.5–4 h
- Component: moveable roof module b
- Component: can bus
- MIL / check engine light
Sources
References
sae:J2012