P0856moderate severityPowertrain
Traction Control Input Signal
on 2023 Chevrolet Bolt EUV 65 kWh Single Motor FWD · FWD
What this code means
The PCM detects a fault in the traction control input signal to the powertrain. This can disable traction control coordination with the engine and transmission.
Symptoms
- Traction control light on
- Reduced engine performance
- ABS/traction faults present
Common causes
- Faulty CAN communication with ABS module
- Wiring fault in signal circuit
- Failed traction control module
- Poor ground or connector corrosion
Diagnostic steps
- Retrieve codes from PCM and ABS module
- Check CAN bus communication integrity
- Inspect signal wiring and connectors
- Repair circuit or replace faulty module
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P0028
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P0029
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P0033
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