Powertrain
Definition only
Lights the check engine lamp
P28B3: Cylinder 9 Ion Current Sense Circuit High
Standardized SAE J2012 code · P28xx codes
What does P28B3 mean?
Ion current from cylinder 9 is above the expected window. Cross-coupled signal, biased reference, or sensor fault.
The code tells you which monitor failed, not which part is broken. Test before replacing parts.
Common causes
- High Inductive cross-coupling from ignition coil primary
- Medium Sense reference voltage biased
- Low Connector pins corroded - high contact resistance
Likelihood is a general estimate across vehicles; your make and model may differ.
Add your car to see reports of P28B3 on the same make and model first.
P28B3 in the community
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Describe your P28B3 problemRelated codes
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- P28AB Cylinder 7 Ion Current Sense Circuit High
- P28AF Cylinder 8 Ion Current Sense Circuit High
- P28B7 Cylinder 10 Ion Current Sense Circuit High
- P28BB Cylinder 11 Ion Current Sense Circuit High
- P28BF Cylinder 12 Ion Current Sense Circuit High