OBD Guide

P21F3

Cylinder 12 Injector B Circuit High

P21F3 is an OBD-II diagnostic trouble code meaning: Cylinder 12 Injector B Circuit High. Common causes: injector circuit short circuit to power, broken or damaged wiring to the injector. Estimated repair cost: $22–89.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$22–89 (est.)

Symptoms

  • Uneven engine operation
  • Power Loss
  • Increased fuel consumption
  • Check Engine Light Is On
  • Possible misfire in cylinder 12

Causes

  • Injector circuit short circuit to power
  • Broken or damaged wiring to the injector
  • Malfunction of the injector itself
  • Problems with the engine control unit
  • Corrosion or poor contact in the injector connector

How to Fix

  1. Check the integrity of the wiring harness to the injector
  2. Measure the injector resistance
  3. Check the voltage in the injector control circuit
  4. If necessary, replace the injector
  5. Check connectors and contacts for corrosion

Related codes

Error P21F3 by Vehicle Brand

FAQ

What does the P21F3 code mean?

P21F3 is an OBD-II diagnostic trouble code that indicates: Cylinder 12 Injector B Circuit High

What causes a P21F3 error code?

The most common causes of P21F3 include: Injector circuit short circuit to power; Broken or damaged wiring to the injector; Malfunction of the injector itself; Problems with the engine control unit.

How do I fix a P21F3 diagnostic trouble code?

To fix P21F3: Check the integrity of the wiring harness to the injector. Measure the injector resistance. Check the voltage in the injector control circuit. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P21F3?

Yes, but get it checked soon

How much does it cost to fix P21F3?

The estimated repair cost for P21F3 is $22–89. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat