P28AA

Cylinder 7 Ion Current Sense Circuit Low

Moderate severity

Ion current from cylinder 7 is below the expected window. Spark plug fouled, signal wire shorted to ground, or sensing path interrupted.

Common causes

Spark plug fouled with carbon or oil
One of the most commonly reported causes for this code — check this first.
high
Typical part cost: $110-770
Sense wire shorted to ground
A plausible cause — test and verify before replacing parts.
medium
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

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Frequently asked questions

What does P28AA mean?

P28AA means "Cylinder 7 Ion Current Sense Circuit Low". It is a generic OBD-II code that points to a fault in the auxiliary emission controls.

What are the most common causes of P28AA?

spark plug fouled with carbon or oil; sense wire shorted to ground; connector pins corroded - high contact resistance — 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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