P2AB2
Catalyst Heater Control Module Supply Voltage
The catalyst heater control module reports supply voltage outside the expected window. Heating output cannot be regulated as expected.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Symptoms
- Check engine light on
- Failed emissions inspection
- Possibly slightly increased fuel consumption
- Sulfur (rotten egg) smell from exhaust under load
Common causes
Ordered by how often each turns out to be the cause.
- Module supply fuse blownCommon
- Alternator regulator driftPossible
Parts involved
- Catalyst Heater Module
- Wiring Harness
P2AB2 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.