OBD Guide

P21EC

Cylinder 9 Injector B Circuit Low

P21EC is an OBD-II diagnostic trouble code meaning: Cylinder 9 Injector B Circuit Low. Common causes: damage to the injector circuit wiring, cylinder 9 injector malfunction. Estimated repair cost: $28–94.

Severity
⚠️ Medium
Can you drive?
Do not drive — repair immediately
Approx. repair cost
$28–94 (est.)

Symptoms

  • Rough engine operation
  • Increased fuel consumption
  • Reduced engine power
  • Engine stalls at idle

Causes

  • Damage to the injector circuit wiring
  • Cylinder 9 injector malfunction
  • Problems with the engine control unit
  • Short circuit in the circuit

How to Fix

  1. Check the condition of the wiring and connectors of the injector
  2. Check injector resistance
  3. Check the control signal from the engine control unit
  4. Replace the injector if necessary

Related codes

Error P21EC by Vehicle Brand

FAQ

What does the P21EC code mean?

P21EC is an OBD-II diagnostic trouble code that indicates: Cylinder 9 Injector B Circuit Low

What causes a P21EC error code?

The most common causes of P21EC include: Damage to the injector circuit wiring; Cylinder 9 injector malfunction; Problems with the engine control unit; Short circuit in the circuit.

How do I fix a P21EC diagnostic trouble code?

To fix P21EC: Check the condition of the wiring and connectors of the injector. Check injector resistance. Check the control signal from the engine control unit. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P21EC?

Do not drive — repair immediately

How much does it cost to fix P21EC?

The estimated repair cost for P21EC is $28–94. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat