P0859 Fault Code

Traction Control Input Signal High

• What does that mean?
• Symptoms
• Causes
• Solutions

The P0859 fault code indicates a problem with the traction control input signal being too high. This signal is crucial as it helps to determine vehicle stability and assists in maintaining traction on slippery surfaces.

What are the symptoms of the P0859 code?

When the P0859 fault code is triggered, you may experience the following symptoms:

• Traction control light illuminated on the dashboard
• Reduced engine power or performance
• Unusual braking behavior during acceleration
• Increased wheel spin or difficulty in maintaining traction, especially in slippery conditions

What causes the P0859 code?

The most common causes for this code include:

• Faulty traction control module
• Wiring issues, such as short circuits or damaged connectors
• Defective brake light switch
• Wheel speed sensor malfunctions
• Issues with the anti-lock braking system (ABS)

How to fix P0859?

To resolve the P0859 fault code, follow these steps:

1. Perform a visual inspection of the vehicle's wiring and connectors related to the traction control system.
2. Check the brake light switch and replace if necessary.
3. Diagnose wheel speed sensors to ensure they are functioning correctly.
4. Use an OBD-II scanner to clear the code and conduct a test drive to see if the code returns.
5. If the issue persists, consider replacing the traction control module or seek professional assistance for further diagnosis.