OBD Guide

P28AA

Cylinder 7 Ion Current Sense Circuit Low

P28AA is an OBD-II diagnostic trouble code meaning: Cylinder 7 Ion Current Sense Circuit Low. Common causes: open or short circuit in the ion current circuit of the 7th cylinder, malfunction of the spark plug of the 7th cylinder. Estimated repair cost: $17–89.

Severity
⚠️ Medium
Can you drive?
Do not drive — repair immediately
Approx. repair cost
$17–89 (est.)

Symptoms

  • Unstable engine idling
  • Reduced engine power
  • Increased fuel consumption
  • Check Engine Light Illuminates
  • Possible misfire

Causes

  • Open or short circuit in the ion current circuit of the 7th cylinder
  • Malfunction of the spark plug of the 7th cylinder
  • Problems with the ignition coil
  • Engine control unit malfunction
  • Poor contact in sensor circuit connector

How to Fix

  1. Check the integrity of wires and connections in the circuit of the 7th cylinder
  2. Replace the spark plug in cylinder 7
  3. Check and, if necessary, replace the ignition coil
  4. Test sensor circuit resistance
  5. Check ECU software for updates

Related codes

Error P28AA by Vehicle Brand

FAQ

What does the P28AA code mean?

P28AA is an OBD-II diagnostic trouble code that indicates: Cylinder 7 Ion Current Sense Circuit Low

What causes a P28AA error code?

The most common causes of P28AA include: Open or short circuit in the ion current circuit of the 7th cylinder; Malfunction of the spark plug of the 7th cylinder; Problems with the ignition coil; Engine control unit malfunction.

How do I fix a P28AA diagnostic trouble code?

To fix P28AA: Check the integrity of wires and connections in the circuit of the 7th cylinder. Replace the spark plug in cylinder 7. Check and, if necessary, replace the ignition coil. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P28AA?

Do not drive — repair immediately

How much does it cost to fix P28AA?

The estimated repair cost for P28AA is $17–89. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat