What are the common causes of P28BB?

A short to voltage on the cylinder 11 ion current sense circuit. High resistance in the cylinder 11 ignition coil wiring. A damaged pin at the cylinder 11 coil connector. A failed ignition coil for cylinder 11. Water intrusion in the cylinder 11 coil connector.

Read ion current sense voltage for cylinder 11. Inspect the cylinder 11 coil connector and pins. Test the cylinder 11 ion sense wiring for shorts to voltage. Swap the cylinder 11 coil with a neighbor and recheck. Replace the cylinder 11 ignition coil if the fault follows it. Clear the code and retest.

P28BB

Cylinder 11 Ion Current Sense Circuit High

System: Transmission (P code)
Lamp: Check Engine Light
Category: Powertrain - Transmission

What it means

P28BB means Cylinder 11 Ion Current Sense Circuit High.

Check these first

A short to voltage on the cylinder 11 ion current sense circuit
High resistance in the cylinder 11 ignition coil wiring
A damaged pin at the cylinder 11 coil connector
A failed ignition coil for cylinder 11
Water intrusion in the cylinder 11 coil connector

What to do next

Read ion current sense voltage for cylinder 11
Inspect the cylinder 11 coil connector and pins
Test the cylinder 11 ion sense wiring for shorts to voltage
Swap the cylinder 11 coil with a neighbor and recheck
Replace the cylinder 11 ignition coil if the fault follows it
Clear the code and retest

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Updated

Generic SAE J2012 definition. Last updated 2026-10-10.