OBD Guide

P1C12

Vacuum Pump Relay Stuck Closed

P1C12 is an OBD-II diagnostic trouble code meaning: Vacuum Pump Relay Stuck Closed. Common causes: faulty vacuum pump relay, short circuit in relay control circuit. Estimated repair cost: $6–28.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$6–28 (est.)

Symptoms

  • Humming sound from vacuum pump
  • Reduced braking system efficiency
  • Increased fuel consumption
  • Check Engine Light Is On
  • Vacuum pump overheating

Causes

  • Faulty vacuum pump relay
  • Short circuit in relay control circuit
  • Problems with the engine control unit
  • Mechanical stuck relay
  • Damaged wiring harness to relay

How to Fix

  1. Check vacuum pump relay
  2. Check relay control circuit for short circuit
  3. Inspect the wiring harness for damage
  4. Replace faulty relay
  5. Check the operation of the vacuum pump after repair

Related codes

FAQ

What does the P1C12 code mean?

P1C12 is an OBD-II diagnostic trouble code that indicates: Vacuum Pump Relay Stuck Closed

What causes a P1C12 error code?

The most common causes of P1C12 include: Faulty vacuum pump relay; Short circuit in relay control circuit; Problems with the engine control unit; Mechanical stuck relay.

How do I fix a P1C12 diagnostic trouble code?

To fix P1C12: Check vacuum pump relay. Check relay control circuit for short circuit. Inspect the wiring harness for damage. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P1C12?

Limited driving only, diagnose soon

How much does it cost to fix P1C12?

The estimated repair cost for P1C12 is $6–28. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat