OBD Guide

P0C21

Electric/Auxiliary Transmission Fluid Pump Phase U-V-W Circuit Low

P0C21 is an OBD-II diagnostic trouble code meaning: Electric/Auxiliary Transmission Fluid Pump Phase U-V-W Circuit Low. Common causes: electrical transmission fluid pump 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

  • Rough gear shifting
  • Reduced transmission performance
  • Check Engine Light Illuminates
  • Noises from the transmission area
  • Transmission overheating

Causes

  • Electrical transmission fluid pump malfunction
  • Wiring harness damage
  • Poor contact in connectors
  • Problems with the transmission control unit
  • Short circuit in the circuit

How to Fix

  1. Check the voltage in the phase circuit U-V-W
  2. Inspect the wiring harness for damage
  3. Check contacts in connectors
  4. Test the transmission fluid pump
  5. Replace pump or wiring harness if necessary

Related codes

Error P0C21 by Vehicle Brand

FAQ

What does the P0C21 code mean?

P0C21 is an OBD-II diagnostic trouble code that indicates: Electric/Auxiliary Transmission Fluid Pump Phase U-V-W Circuit Low

What causes a P0C21 error code?

The most common causes of P0C21 include: Electrical transmission fluid pump malfunction; Wiring harness damage; Poor contact in connectors; Problems with the transmission control unit.

How do I fix a P0C21 diagnostic trouble code?

To fix P0C21: Check the voltage in the phase circuit U-V-W. Inspect the wiring harness for damage. Check contacts in connectors. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P0C21?

Limited driving only, diagnose soon

How much does it cost to fix P0C21?

The estimated repair cost for P0C21 is $56–167. Actual cost depends on your vehicle, location, and labor rates.

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