OBD Guide

P21D7

Cylinder 9 Injector B Circuit/Open

P21D7 is an OBD-II diagnostic trouble code meaning: Cylinder 9 Injector B Circuit/Open. Common causes: open or short circuit in the injector circuit, cylinder 9 injector malfunction. Estimated repair cost: $17–89.

Severity
⚠️ Medium
Can you drive?
Do not drive — repair immediately
Approx. repair cost
$17–89 (est.)

Symptoms

  • Misfire in cylinder 9
  • Reduced engine power
  • Increased fuel consumption
  • Unstable engine idling
  • Check Engine Light Illuminates

Causes

  • Open or short circuit in the injector circuit
  • Cylinder 9 injector malfunction
  • Wiring harness damage
  • Problems with the engine control unit
  • Oxidation of injector connector contacts

How to Fix

  1. Check the integrity of the injector wiring and connectors
  2. Test injector resistance
  3. Check for voltage at the injector connector
  4. Replace the faulty injector if necessary
  5. Clean or replace oxidized contacts

Related codes

Error P21D7 by Vehicle Brand

FAQ

What does the P21D7 code mean?

P21D7 is an OBD-II diagnostic trouble code that indicates: Cylinder 9 Injector B Circuit/Open

What causes a P21D7 error code?

The most common causes of P21D7 include: Open or short circuit in the injector circuit; Cylinder 9 injector malfunction; Wiring harness damage; Problems with the engine control unit.

How do I fix a P21D7 diagnostic trouble code?

To fix P21D7: Check the integrity of the injector wiring and connectors. Test injector resistance. Check for voltage at the injector connector. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P21D7?

Do not drive — repair immediately

How much does it cost to fix P21D7?

The estimated repair cost for P21D7 is $17–89. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat