OBD Guide

P28B9

Cylinder 11 Ion Current Sense Circuit Range/Performance

P28B9 is an OBD-II diagnostic trouble code meaning: Cylinder 11 Ion Current Sense Circuit Range/Performance. Common causes: open or short circuit in the ion current circuit, faulty spark plug. Estimated repair cost: $6–56.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$6–56 (est.)

Symptoms

  • Unstable engine operation
  • Increased fuel consumption
  • Power Loss
  • Check Engine Light Illuminates
  • Possible misfires

Causes

  • Open or short circuit in the ion current circuit
  • Faulty spark plug
  • Problems with the ignition coil
  • Engine control unit malfunction
  • Poor contact in connectors

How to Fix

  1. Check the integrity of the ion current circuit wiring
  2. Inspect and, if necessary, replace the spark plug
  3. Check the condition of the ignition coil
  4. Scan the control unit for errors
  5. Check contacts in connectors

Related codes

Error P28B9 by Vehicle Brand

FAQ

What does the P28B9 code mean?

P28B9 is an OBD-II diagnostic trouble code that indicates: Cylinder 11 Ion Current Sense Circuit Range/Performance

What causes a P28B9 error code?

The most common causes of P28B9 include: Open or short circuit in the ion current circuit; Faulty spark plug; Problems with the ignition coil; Engine control unit malfunction.

How do I fix a P28B9 diagnostic trouble code?

To fix P28B9: Check the integrity of the ion current circuit wiring. Inspect and, if necessary, replace the spark plug. Check the condition of the ignition coil. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P28B9?

Yes, but get it checked soon

How much does it cost to fix P28B9?

The estimated repair cost for P28B9 is $6–56. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat