Powertrain
Definition only
Lights the check engine lamp
P28B2: Cylinder 9 Ion Current Sense Circuit Low
Standardized SAE J2012 code · P28xx codes
What does P28B2 mean?
Ion current from cylinder 9 is below the expected window. Spark plug fouled, signal wire shorted to ground, or sensing path interrupted.
The code tells you which monitor failed, not which part is broken. Test before replacing parts.
Common causes
- High Spark plug fouled with carbon or oil
- Medium Sense wire shorted to ground
- 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 P28B2 on the same make and model first.
P28B2 in the community
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