C0089: Traction Control System (TCS) Disable Switch (Subfault)

What it means

This code identifies a fault associated with the TCS disable switch. The specific failure depends on the diagnostic subtype.

How it works

The TCS disable switch lets the driver request that traction control be turned off or changed to a permitted state. The control module monitors the switch input and its circuit, and sets this subfault when the input is missing, implausible, or otherwise fails the subtype-specific test.

Common causes

Most likely first.

1. Switch failed or wiring fault

Symptoms

• Traction-control warning light
• Traction-control disable switch may not work as expected

How to diagnose it

1. Read the diagnostic subtype and freeze-frame data, then note whether the traction-control warning is present and whether pressing the disable switch changes system status.
2. Inspect the TCS disable switch for physical damage, sticking, contamination, or a connector that is loose or corroded.
3. Check the switch wiring for chafing, open circuits, shorts, and poor connections, following the wiring diagram for the vehicle.
4. Use a scan tool to watch the TCS switch input while pressing and releasing the switch, confirming that the reported state changes consistently.
5. Test the switch and its circuit against the manufacturer's specification before replacing the switch or control module.

Common fixes

• Clean or reconnect the TCS disable switch connector and repair any damaged wiring.
• Replace a sticking or electrically failed TCS disable switch.
• Repair a poor power, ground, or signal connection in the switch circuit.
• Repair or replace the control module only if switch and circuit tests point to an internal fault.

Can I keep driving?

Traction control may not respond to the disable switch, or it may be unavailable, so drive gently on wet, icy, or loose surfaces. Avoid relying on the switch to change traction control status until the fault is resolved.