OBD Guide

P21DB

Cylinder 1 Injector B Circuit Low

P21DB is an OBD-II diagnostic trouble code meaning: Cylinder 1 Injector B Circuit Low. Common causes: malfunction of injector b of cylinder 1, open or short circuit in the injector control circuit. Estimated repair cost: $17–89.

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

Symptoms

  • Unstable engine operation
  • Increased fuel consumption
  • Misfire in cylinder 1
  • Check Engine Light Illuminates
  • Reduced engine power

Causes

  • Malfunction of injector B of cylinder 1
  • Open or short circuit in the injector control circuit
  • Poor contact in the injector connector
  • Engine control unit malfunction
  • Wiring harness damage

How to Fix

  1. Check the resistance of injector B of cylinder 1
  2. Inspect the injector control circuit for damage.
  3. Check the contacts in the injector connector
  4. Scan the engine control module for additional errors
  5. If necessary, replace the injector or repair the wiring

Related codes

Error P21DB by Vehicle Brand

FAQ

What does the P21DB code mean?

P21DB is an OBD-II diagnostic trouble code that indicates: Cylinder 1 Injector B Circuit Low

What causes a P21DB error code?

The most common causes of P21DB include: Malfunction of injector B of cylinder 1; Open or short circuit in the injector control circuit; Poor contact in the injector connector; Engine control unit malfunction.

How do I fix a P21DB diagnostic trouble code?

To fix P21DB: Check the resistance of injector B of cylinder 1. Inspect the injector 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 P21DB?

Limited driving only, diagnose soon

How much does it cost to fix P21DB?

The estimated repair cost for P21DB is $17–89. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat