Code result
P28B3
Cylinder 9 Ion Current Sense Circuit High
Moderate severity
What it means
Ion current from cylinder 9 is above the expected window. Cross-coupled signal, biased reference, or sensor fault.
Is it safe to drive?
Use caution
The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical.
Most likely causes
Inductive cross-coupling from ignition coil primary
highOne of the most commonly reported causes for this code — check this first.
Sense reference voltage biased
mediumA plausible cause — test and verify before replacing parts.
Connector pins corroded - high contact resistance
lowLess common, but worth ruling out after the more likely causes.
Related help
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