P2AB2Catalyst Heater Control Module Supply Voltage
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P2AB2 points to the power feed of the catalyst heater control module: the voltage it measures at its own supply input lies outside the window in which it may switch the heater. That window matters because these heaters draw several kilowatts; Vitesco's demonstration vehicle used a 4 kW disc, fed in 48-volt mild hybrids from energy recovered while braking, as DieselNet reports. Mitsubishi Electric's patent US5388404A shows the logic behind such a check: the controller first compares battery voltage with a reference and only then closes the heater current switch, guided by a catalyst temperature signal. No manufacturer documents P2AB2 publicly. A blown fuse, a corroded ground, a weak 48-volt battery or a faulty DC/DC converter are typical finds. P0562 and P0563 cover the general system voltage.
- What you may notice
- Check engine light on
- Catalyst heating not available, higher emissions after cold start
- Further voltage-related fault codes possible
- Likely causes
- LikelyBlown fuse or faulty relay in the heater supply
- PossibleCorroded or loose ground or high-current terminal
- PossibleWeak 48-volt battery or faulty DC/DC converter in mild-hybrid systems
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €30 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.