Ion Sense System Performance
Some engines (notably Saab and some Mazda direct-injection units) use the spark plug as an ion-current sensor after spark to detect knock and misfire. This code reports a performance issue with the ion-sense input — typically a worn plug, loose secondary connection, or aged ion-sense module.
Affected components
- Ion sense module
- Spark plug
- Ignition coil
Common causes
- High likelihood: Spark plugs worn
- Medium likelihood: Ion-sense module aged
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.