OBD Guide

P21D9

Cylinder 11 Injector B Circuit/Open

P21D9 is an OBD-II diagnostic trouble code meaning: Cylinder 11 Injector B Circuit/Open. Common causes: broken or damaged injector circuit wires, cylinder 11 injector malfunction. Estimated repair cost: $17–89.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$17–89 (est.)

Symptoms

  • Misfire in cylinder 11
  • Reduced engine power
  • Unstable engine idling
  • Increased fuel consumption
  • Check Engine light comes on

Causes

  • Broken or damaged injector circuit wires
  • Cylinder 11 injector malfunction
  • Problems with the injector connector
  • Malfunction of the engine control unit (ECU)
  • Blown fuse or faulty relay

How to Fix

  1. Check the integrity of the injector circuit wires
  2. Check the condition of the injector connector
  3. Check injector resistance
  4. Replace the faulty injector if necessary
  5. Check and replace fuses or relays

Related codes

Error P21D9 by Vehicle Brand

FAQ

What does the P21D9 code mean?

P21D9 is an OBD-II diagnostic trouble code that indicates: Cylinder 11 Injector B Circuit/Open

What causes a P21D9 error code?

The most common causes of P21D9 include: Broken or damaged injector circuit wires; Cylinder 11 injector malfunction; Problems with the injector connector; Malfunction of the engine control unit (ECU).

How do I fix a P21D9 diagnostic trouble code?

To fix P21D9: Check the integrity of the injector circuit wires. Check the condition of the injector connector. Check injector resistance. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P21D9?

Limited driving only, diagnose soon

How much does it cost to fix P21D9?

The estimated repair cost for P21D9 is $17–89. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat