Network
generic / SAE
U02A5
Lost Communication With Reductant Heater Control Module
The vehicle bus reports loss of communication with the reductant heater module. AdBlue lines and tank can no longer be thawed at low temperatures, blocking SCR operation in winter.
SystemNetwork
Typegeneric / SAE
GroupU0
Range / number2 / A5
Possible causes
- Bus wiring open or shorted high
- Module without power or ground medium
- Module failed medium
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: 200–1200 €
- Estimated time: 0.5–3 h
- Component: reductant heater module
- Component: vehicle bus wiring
- MIL / check engine light
- emissions-relevant
- drive cycle required
Sources
References
sae:J2012