P28A4
Cylinder 6 Ion Current Sense Circuit
The ECM cannot read a valid ion current signal from cylinder 6. Ion current sensing relies on the spark plug acting as an electrode after combustion.
The ECM cannot read a valid ion current signal from cylinder 6. Ion current sensing relies on the spark plug acting as an electrode after combustion.
Common causes
- high
Ion sense module failed
One of the most commonly reported causes for this code — check this first.
Typical part cost: $110-770
- medium
Wiring or connector fault
A plausible cause — test and verify before replacing parts.
Typical part cost: $110-770
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First things to check
- 1Confirm the code with a scan tool and check for additional related codes.
- 2Inspect the relevant sensors, wiring, and connectors for damage or corrosion.
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Related codes
See related trouble codes
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Frequently asked questions
What does P28A4 mean?
P28A4 means "Cylinder 6 Ion Current Sense Circuit". It is a generic OBD-II code that points to a fault in the auxiliary emission controls.
What are the most common causes of P28A4?
ion sense module failed; wiring or connector fault — these are the most commonly reported causes. Verify with a proper diagnosis before replacing parts, or use the Wrenchify app for a vehicle-specific diagnosis.
Can I keep driving with this code?
The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical. Use the Wrenchify app for a full diagnosis specific to your vehicle.
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