OBD Guide

P289C

Cylinder 4 Ion Current Sense Circuit

P289C is an OBD-II diagnostic trouble code meaning: Cylinder 4 Ion Current Sense Circuit. Common causes: open or short circuit in the ion current circuit, malfunction of the spark plug of the 4th cylinder. Estimated repair cost: $6–33.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$6–33 (est.)

Symptoms

  • Unstable engine operation
  • Misfire in cylinder 4
  • Increased fuel consumption
  • Reduced engine power
  • Check Engine Light Illuminates

Causes

  • Open or short circuit in the ion current circuit
  • Malfunction of the spark plug of the 4th cylinder
  • Wiring harness damage
  • Engine control unit malfunction
  • Poor contact in connectors

How to Fix

  1. Check the condition of the spark plug in the 4th cylinder
  2. Check the integrity of the ion current circuit
  3. Inspect connectors and wiring harness for damage
  4. Check the resistance of the ion current circuit
  5. If necessary, replace the spark plug or repair the wiring

Related codes

Error P289C by Vehicle Brand

FAQ

What does the P289C code mean?

P289C is an OBD-II diagnostic trouble code that indicates: Cylinder 4 Ion Current Sense Circuit

What causes a P289C error code?

The most common causes of P289C include: Open or short circuit in the ion current circuit; Malfunction of the spark plug of the 4th cylinder; Wiring harness damage; Engine control unit malfunction.

How do I fix a P289C diagnostic trouble code?

To fix P289C: Check the condition of the spark plug in the 4th cylinder. Check the integrity of the ion current circuit. Inspect connectors and wiring harness for damage. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P289C?

Yes, but get it checked soon

How much does it cost to fix P289C?

The estimated repair cost for P289C is $6–33. Actual cost depends on your vehicle, location, and labor rates.

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