Fault codeP0857

MODERATE

Traction Control Input Signal Range/Performance

What this code means

Traction Control Input Signal Range/Performance.

P0857 is a generic code: it means the same thing on every make. P0857 belongs to family P08xx — Transmission (continued). Its page explains how to read a code and groups all its codes by part.

Type of fault

The signal stays within its electrical limits, but its value is not plausible: it does not match what the control unit expects given the other sensors. The sensor may be drifting with age, but it may also be faithfully measuring a real mechanical problem — a leak, a blockage, an air leak. Replacing the sensor without checking does not always clear the fault.

Traction control signal

The traction control unit, part of the ABS/ESP system, asks the engine control unit to cut torque when a wheel slips. These codes concern the signal between the two.

What you notice

Traction control or ESP warnings, power that drops unexpectedly or a system that does not intervene.

How to check it

Read the codes of the ABS/ESP unit too: the source of the fault is often there, such as a wheel speed sensor. Then check the communication wiring between the modules.

What to do

Have it checked this week. The car remains usable, but the fault will not clear itself and will fail the roadworthiness test.

Clearing a code switches the light off but repairs nothing: if the fault remains, the code comes back. Clearing a fault code yourself →

How to read this code

PPowertrain
0standardised code
8Transmission (continued)
57P0857