Traction Control Input Signal Range/Performance
What does P0857 mean?
The P0857 code means the vehicle's onboard diagnostic system has detected: Traction Control Input Signal Range/Performance. This is a moderate severity code.
Common Symptoms
- Check Engine Light illuminated
- Traction control light on
- Inconsistent traction control intervention
- Transmission shifts may not adapt to road conditions
Probable Causes (Ranked by Likelihood)
- Erratic wheel speed sensor signal Very High
- Traction control module sending out-of-range data to TCM High
- CAN bus communication interference Moderate
- ABS module internal processing error Low
Step-by-Step Diagnostic Procedure
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Monitor all four wheel speed sensor signals for erratic readings
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Check traction control data sent to TCM on the CAN bus
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Inspect wheel speed sensor tone rings for damage or debris
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Verify ABS module firmware is up to date
Frequently Asked Questions
What does range/performance mean for traction control signal?
The signal is present but contains values that are outside the expected range or do not change appropriately with driving conditions.
Can dirty wheel speed sensors cause P0857?
Yes, debris buildup on the wheel speed sensor or its tone ring can cause erratic readings that confuse the traction control system.
Will cleaning the sensors fix the code?
It might. Cleaning the sensor face and tone ring is a free first step. If the sensor air gap is within spec and the code returns, the sensor may need replacement.