Network
generic / SAE
U01BD
Lost Communication With DC/DC Converter Control Module C
ECU lost communication with DC/DC converter module C (steps HV battery down to 12V on hybrids/EVs). 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 / number1 / BD
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: hard
- DIY: shop recommended
- Estimated cost: 300–2500 €
- Estimated time: 1–6 h
- Component: dcdc converter module c
- Component: can bus
- MIL / check engine light
- drive cycle required
- limp mode possible
Sources
References
sae:J2012