OBD Guide

P21D4

Cylinder 6 Injector B Circuit/Open

P21D4 is an OBD-II diagnostic trouble code meaning: Cylinder 6 Injector B Circuit/Open. Common causes: cylinder 6 injector malfunction, broken or damaged injector wires. Estimated repair cost: $28–89.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$28–89 (est.)

Symptoms

  • Unstable engine operation
  • Misfire in cylinder 6
  • Power Loss
  • Increased fuel consumption
  • Check Engine Light Is On

Causes

  • Cylinder 6 injector malfunction
  • Broken or damaged injector wires
  • Poor contact in the injector connector
  • Control module malfunction
  • Short circuit in the circuit

How to Fix

  1. Check injector resistance
  2. Inspect wiring and connectors for damage
  3. Check the presence of a control signal from the ECU
  4. Replace the injector if necessary
  5. Clear contacts and restore connections

Related codes

Error P21D4 by Vehicle Brand

FAQ

What does the P21D4 code mean?

P21D4 is an OBD-II diagnostic trouble code that indicates: Cylinder 6 Injector B Circuit/Open

What causes a P21D4 error code?

The most common causes of P21D4 include: Cylinder 6 injector malfunction; Broken or damaged injector wires; Poor contact in the injector connector; Control module malfunction.

How do I fix a P21D4 diagnostic trouble code?

To fix P21D4: Check injector resistance. Inspect wiring and connectors for damage. Check the presence of a control signal from the ECU. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P21D4?

Limited driving only, diagnose soon

How much does it cost to fix P21D4?

The estimated repair cost for P21D4 is $28–89. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat