P2AB1 — Catalyst Heater Control Module Performance
The ECM detects that the catalyst heater control module does not respond to commands within the expected window. Heating output is reduced or absent during catalyst light-off.
General code reference. Confirm the definition and diagnostic procedure for your vehicle's year, model and engine. A stored code alone does not identify a failed part.
Affected components
- Catalyst heater module
- Catalyst heater element
Possible causes to check
These are possible checks, not a ranked diagnosis. Follow the vehicle manufacturer's test procedure before replacing parts.
- Internal control module fault
- Communication with ECM degraded
- Module software outdated, reflash may resolve
Possible symptoms
- Check engine light on
- Failed emissions inspection
- Possibly slightly increased fuel consumption
- Sulfur (rotten egg) smell from exhaust under load
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
- A drive cycle may be required after repair
Sources
Check each reference's vehicle and model-year scope. General background links do not establish which fault is most likely on your vehicle.
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.