Network
generic / SAE
U0120
Lost Communication with Starter/Generator Control Module
The Starter/Generator Control Module has stopped transmitting on the vehicle data bus, so other control units no longer receive its messages. Stop-start and mild-hybrid generator functions stop working. Typical causes are loss of power or ground at the module, an open or shorted CAN/LIN bus wire, a connector fault, or an internal module failure.
SystemNetwork
Typegeneric / SAE
GroupU0
Range / number1 / 20
Possible causes
- Starter/generator module unpowered high
- CAN wiring to starter/generator broken medium
- Gateway module routing CAN messages incorrectly 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
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References
sae:J2012