What it means
The ECM detects a generic fault on the supply voltage circuit of the ion sense module. The module can no longer reliably bias the spark plug for ion current measurement.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The ion-sense module needs a supply voltage to bias the spark plug so it can measure ion current after ignition. This code sets when the engine control module detects a general fault in that supply circuit, without identifying the fault specifically as low or high voltage.
Common causes
Most likely first.
- Module supply rail interrupted
- Wiring or connector fault
Symptoms
- Check-engine light
- Reduced power
- Hard starting or stalling
How to diagnose it
- Check freeze-frame data and related power-supply or ion-sense codes to see when the fault occurred and whether it points to a shared supply problem.
- Inspect the ion-sense module connector, supply wiring, and relevant fuse for loose connections, corrosion, damage, or an interrupted circuit.
- With the circuit checked under the conditions specified by the manufacturer, verify that supply voltage reaches the module.
- Check the supply circuit for continuity and unwanted shorts, following the manufacturer's wiring diagram and test procedure.
- If the wiring and supply are sound, test the module and its upstream supply source according to the manufacturer's procedure.
Common fixes
- Secure a loose ion-sense module connector or repair damaged supply wiring.
- Replace a confirmed blown supply fuse after checking for the cause of the fuse failure.
- Repair an interrupted supply circuit or faulty upstream supply connection.
- Replace the ion-sense module only if its supply is correct and testing confirms an internal fault.
Can I keep driving?
Driving may be unreliable because the module may not be able to measure combustion consistently; hard starting, stalling, or reduced power can occur. Avoid journeys where a stall would be hazardous, and stop if the engine repeatedly stalls.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.