OBD Guide

C0166

TCS Priming Line Valve Circuit Malfunction

C0166 is an OBD-II diagnostic trouble code meaning: TCS Priming Line Valve Circuit Malfunction. Common causes: open or short circuit in the tcs purge valve circuit, tcs purge valve malfunction. Estimated repair cost: $56–167.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$56–167 (est.)

Symptoms

  • Check Engine Light Is On
  • Unstable operation of the traction control system
  • Reduced braking performance on slippery surfaces

Causes

  • Open or short circuit in the TCS purge valve circuit
  • TCS purge valve malfunction
  • Problems with the TCS control unit
  • Wiring harness damage

How to Fix

  1. Check the continuity of the TCS purge valve circuit
  2. Test TCS purge valve resistance
  3. Check control signals from the TCS control unit
  4. Replace TCS purge valve if necessary
  5. Repair wiring damage

Related codes

Error C0166 by Vehicle Brand

FAQ

What does the C0166 code mean?

C0166 is an OBD-II diagnostic trouble code that indicates: TCS Priming Line Valve Circuit Malfunction

What causes a C0166 error code?

The most common causes of C0166 include: Open or short circuit in the TCS purge valve circuit; TCS purge valve malfunction; Problems with the TCS control unit; Wiring harness damage.

How do I fix a C0166 diagnostic trouble code?

To fix C0166: Check the continuity of the TCS purge valve circuit. Test TCS purge valve resistance. Check control signals from the TCS control unit. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with C0166?

Limited driving only, diagnose soon

How much does it cost to fix C0166?

The estimated repair cost for C0166 is $56–167. Actual cost depends on your vehicle, location, and labor rates.

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