What it means
Ion current from cylinder 6 is above the expected window. Cross-coupled signal, biased reference, or sensor fault.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The ECM assesses combustion at cylinder 6 by reading ion current through its spark plug after the spark. This code sets when the signal is higher than expected, which can result from ignition-coil interference, a biased sense reference, or a sensing fault.
Common causes
Most likely first.
- Inductive cross-coupling from ignition coil primary
- Sense reference voltage biased
- Connector pins corroded - high contact resistance
Symptoms
- Check-engine light on
- Rough idle or engine misfire
- Reduced engine performance
How to diagnose it
- Review freeze-frame and live ion-sense readings to confirm the high signal is on cylinder 6 and identify when it occurs.
- Inspect the cylinder 6 ion-sense connector for corrosion, loose pins, or contamination that could affect the reference.
- Check whether cylinder 6 sense wiring is damaged or routed close to ignition-coil primary wiring, which can couple interference into the signal.
- Check the cylinder 6 sense reference for an unintended bias or short using the manufacturer's circuit information.
- Test the reference and sensing path against the manufacturer's specification, then isolate the sensor or module only if wiring checks pass.
Common fixes
- Clean and secure corroded or loose cylinder 6 connector contacts.
- Repair damaged cylinder 6 sense wiring and restore its specified routing away from ignition-coil wiring.
- Repair a confirmed fault in the cylinder 6 sense reference circuit.
- Replace the faulty cylinder 6 ion-sense element or module if testing confirms a high-biased signal.
Can I keep driving?
If the engine runs smoothly, keep trips short and avoid hard acceleration until the cylinder 6 signal is checked; the ECM may assess combustion incorrectly and emissions can rise. Stop if the engine develops a severe misfire or marked power loss.
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.