OBD Guide

P166A

Restraints Deployment Communication Circuit

P166A is an OBD-II diagnostic trouble code meaning: Restraints Deployment Communication Circuit. Common causes: open or short circuit in the communication circuit, poor contact in security system connectors. Estimated repair cost: $17–111.

Severity
🔴 High
Can you drive?
Do not drive — repair immediately
Approx. repair cost
$17–111 (est.)

Symptoms

  • Airbag light is on
  • The safety system may not work in an accident
  • The error may appear after repairs or an accident.
  • Possible problems with other security systems

Causes

  • Open or short circuit in the communication circuit
  • Poor contact in security system connectors
  • Airbag module malfunction
  • Damage to the wiring harness after an accident
  • Airbag module power supply problems

How to Fix

  1. Check the continuity of the communication circuit using a multimeter
  2. Inspect connectors and contacts for oxidation or damage
  3. Check the power and ground of the airbag module
  4. If necessary, replace damaged wires or connectors
  5. Repair only from an authorized dealer

Related codes

FAQ

What does the P166A code mean?

P166A is an OBD-II diagnostic trouble code that indicates: Restraints Deployment Communication Circuit

What causes a P166A error code?

The most common causes of P166A include: Open or short circuit in the communication circuit; Poor contact in security system connectors; Airbag module malfunction; Damage to the wiring harness after an accident.

How do I fix a P166A diagnostic trouble code?

To fix P166A: Check the continuity of the communication circuit using a multimeter. Inspect connectors and contacts for oxidation or damage. Check the power and ground of the airbag module. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P166A?

Do not drive — repair immediately

How much does it cost to fix P166A?

The estimated repair cost for P166A is $17–111. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat