Home›Trouble Codes›C0085

C0085 — Traction Disable Indicator

Generic OBD-II · all makesChassis

C0085 sets when the traction control system detects a fault or is commanded off, illuminating the traction disable indicator on the dashboard. The code indicates that the system cannot function properly, often because a related sensor or module has reported an abnormal condition. It does not directly affect engine operation but disables traction and stability aids that help maintain vehicle control.

Symptoms

What causes it — most likely first

1. Faulty wheel speed sensor

A wheel speed sensor may fail, send erratic signals, or lose ground, causing the traction control system to disable and set C0085.

2. Damaged wiring or connectors

Corroded, broken, or unplugged wiring in the sensor circuit can interrupt signals, leading the module to turn off traction control.

3. ABS/traction control module internal failure

The ABS/traction control module can develop internal faults, preventing proper control and lighting the disable indicator.

4. Faulty steering angle or yaw rate sensor

If the steering angle or yaw rate sensor provides incorrect data, the system may disable traction control as a safety measure.

5. Traction control switch stuck in off position

A stuck or defective traction-control on/off switch can keep the system in the disabled state, triggering the code.

6. PCM/ECM misinterpretation (rare)

While uncommon, the PCM can misinterpret sensor data and erroneously command the traction system off; this should be investigated after other components are ruled out.

How it's diagnosed

  1. Connect an OBD-II scan tool and record all stored codes, noting any related wheel-speed or ABS codes.
  2. Visually inspect the wheel-speed sensors, connectors, and wiring for damage, corrosion, or loose fits.
  3. Measure the resistance and AC signal of each wheel-speed sensor with a multimeter or oscilloscope to verify proper operation.
  4. Perform ABS/traction-control module self-test (if supported by the scan tool) to check for internal faults.
  5. Test the steering-angle and yaw-rate sensors (if present) for correct values and communication.
  6. Confirm the traction-control switch is not stuck in the off position and verify system operation after repairs.

Code facts & related codes

SystemChassis
StandardizationSAE generic — identical on every make
Related codesC0081 — Abs Malfunction IndicatorC0082 — Brake System Malfunction IndicatorC0083 — Tire Pressure Monitor Malfunction IndiC0084 — Traction Active IndicatorC0086 — Vehicle Dynamics IndicatorC0089 — Tcs Disable Switch

Frequently asked

Is it safe to drive with the traction disable light on?

You can still drive, but traction control will not assist you; drive cautiously and have the issue diagnosed soon.

I was told to replace the PCM for C0085 – is that necessary?

In most cases the PCM is not the problem; the fault usually lies in sensors, wiring, or the ABS/traction module, so PCM replacement is rarely required.

Can a low battery or weak charging system cause this code?

Low voltage can cause modules to reset and may set a temporary code; after battery/alternator issues are fixed, clear the code and see if it returns.

Will clearing the code turn off the light permanently?

Clearing the code only erases the stored data; if the underlying fault remains, the light will come back on after the next drive cycle.