OBD Guide

C0091

4WD/AWD Power Transfer Unit Position Sensor A

C0091 is an OBD-II diagnostic trouble code meaning: 4WD/AWD Power Transfer Unit Position Sensor A. Common causes: position sensor malfunction, wiring harness damage. Estimated repair cost: $56–167.

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

Symptoms

  • Incorrect operation of the all-wheel drive system
  • Check engine light comes on
  • The car goes into emergency mode
  • Unusual noises from the transfer case

Causes

  • Position sensor malfunction
  • Wiring harness damage
  • Poor contact in the sensor connector
  • Mechanical damage to the transfer case
  • Transmission control unit malfunction

How to Fix

  1. Check the integrity of the wiring harness
  2. Clean sensor contacts
  3. Check sensor resistance
  4. Replace position sensor if necessary
  5. Check the mechanical condition of the transfer case

Related codes

Error C0091 by Vehicle Brand

FAQ

What does the C0091 code mean?

C0091 is an OBD-II diagnostic trouble code that indicates: 4WD/AWD Power Transfer Unit Position Sensor A

What causes a C0091 error code?

The most common causes of C0091 include: Position sensor malfunction; Wiring harness damage; Poor contact in the sensor connector; Mechanical damage to the transfer case.

How do I fix a C0091 diagnostic trouble code?

To fix C0091: Check the integrity of the wiring harness. Clean sensor contacts. Check sensor resistance. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with C0091?

Limited driving only, diagnose soon

How much does it cost to fix C0091?

The estimated repair cost for C0091 is $56–167. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat