Faulty traction control mode switch or button; Damaged or corroded wiring or connector at the mode switch; Internal failure of the TCS/ABS control module; Poor ground connection for the TCS module or switch; Water intrusion into the switch or connector causing intermittent shorts; Software glitch or corrupted module calibration

DTC codes / C00xx · Brakes, steering and suspension / C008A

C008ATCS Mode Control

Q: What does code C008A mean?

TCS Mode Control. C008A indicates that the traction control system (TCS) module has detected an internal fault in its mode control circuit or logic, preventing it from properly switching between traction control modes. The computer sets this code when the TCS mode control signal is out of expected range or the module cannot confirm the requested mode, often due to a faulty switch, wiring issue, or internal module failure.

C008A indicates that the traction control system (TCS) module has detected an internal fault in its mode control circuit or logic, preventing it from properly switching between traction control modes. The computer sets this code when the TCS mode control signal is out of expected range or the module cannot confirm the requested mode, often due to a faulty switch, wiring issue, or internal module failure.

SystemChassis

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaBrakes, steering and suspension

Symptoms you may notice

Traction control warning light illuminated on the dashboard
Traction control system may be disabled, allowing wheel spin on slippery surfaces
Stability control (ESC) light may also be on if systems are integrated
Often no symptoms besides the warning light
Possible intermittent operation of traction control modes if equipped with a mode selector
Cruise control may be disabled as a precaution in some vehicles

Common causes, most likely first

Faulty traction control mode switch or button
Damaged or corroded wiring or connector at the mode switch
Internal failure of the TCS/ABS control module
Poor ground connection for the TCS module or switch
Water intrusion into the switch or connector causing intermittent shorts
Software glitch or corrupted module calibration

How to diagnose and fix it

Scan all modules for stored codes and freeze frame data to confirm C008A is current
Inspect the traction control mode switch for physical damage or sticking, and test its continuity
Check wiring and connectors between the switch and the TCS module for corrosion, chafing, or loose pins
Verify power and ground supplies to the TCS module, including grounds for cleanliness and tightness
Perform a module reset or software update if applicable, following manufacturer procedures
If all external circuits test good, replace and reprogram the TCS/ABS control module as needed
Clear codes and perform a road test to verify the repair and ensure no pending codes return

Common misdiagnosis of C008A

A faulty mode switch is often overlooked because the switch may still feel normal but have high resistance internally, causing the module to set the code intermittently.
Water intrusion into the switch or connector is a frequent cause, especially on vehicles where the switch is located in the center console or near cup holders.
The code can be set by a low battery or charging system issue that causes voltage spikes, so always check battery health and charging voltage before replacing modules.
On some vehicles, the TCS mode control is integrated into the ABS module, and a failure in the ABS system can trigger C008A as a secondary code.
After replacing the TCS module, programming and calibration are often required; skipping this step can lead to repeat codes or improper operation.

Can I keep driving with C008A?

You can generally continue driving with C008A, but be aware that traction control may be disabled, reducing stability on slippery surfaces. Avoid aggressive acceleration or sharp maneuvers in wet or icy conditions, and have the system inspected soon to restore full safety features.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.