Cylinder 9 Ion Current Sense Circuit
The ECM cannot read a valid ion current signal from cylinder 9. Ion current sensing relies on the spark plug acting as an electrode after combustion.
Affected components
- Spark plug cyl 9
- Ignition coil cyl 9
- Ion sense module
Common causes
- High likelihood: Ion sense module failed
- Medium likelihood: Wiring or connector fault
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
Related codes
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.