OBD Guide

P21EF

Cylinder 10 Injector B Circuit High

P21EF is an OBD-II diagnostic trouble code meaning: Cylinder 10 Injector B Circuit High. Common causes: cylinder 10 injector malfunction, open or short circuit in control circuit. Estimated repair cost: $33–167.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$33–167 (est.)

Symptoms

  • Uneven engine operation
  • Increased fuel consumption
  • Misfire in cylinder 10
  • Check Engine Light Illuminates
  • Reduced engine power

Causes

  • Cylinder 10 injector malfunction
  • Open or short circuit in control circuit
  • Poor contact in the injector connector
  • Engine control unit malfunction
  • Wiring harness damage

How to Fix

  1. Check the resistance of the injector of cylinder 10
  2. Inspect the control circuit for damage
  3. Check the contacts in the injector connector
  4. Test the operation of the injector driver in the ECU
  5. If necessary, replace the nozzle or repair the wiring

Related codes

Error P21EF by Vehicle Brand

FAQ

What does the P21EF code mean?

P21EF is an OBD-II diagnostic trouble code that indicates: Cylinder 10 Injector B Circuit High

What causes a P21EF error code?

The most common causes of P21EF include: Cylinder 10 injector malfunction; Open or short circuit in control circuit; Poor contact in the injector connector; Engine control unit malfunction.

How do I fix a P21EF diagnostic trouble code?

To fix P21EF: Check the resistance of the injector of cylinder 10. Inspect the control circuit for damage. Check the contacts in the injector connector. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P21EF?

Yes, but get it checked soon

How much does it cost to fix P21EF?

The estimated repair cost for P21EF is $33–167. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat