P23DACylinder 3 Fuel Heater Control Circuit High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P23DA tells that the control side of the cylinder 3 heater sits at a high level. The likely pictures are a control wire touching a positive feed, so voltage stays on the line when the channel is off, or an output stage that has failed conducting, so heater 3 runs without command. The second case is the costly one: Bosch rates one heat circuit at about 260 W at 12 V, which is more than 20 A, and a heater that keeps running after the engine is shut off will drain the battery within a few hours. A heater 3 that is still warm long after switch-off, or an unexplained flat battery, fits this code. No manufacturer publishes P23DA; CARB requires the circuit to be monitored. Low fault: P23DB, open: P23D9, cylinder 2 counterpart: P23D6.
- What you may notice
- Flat battery after the car has stood for some hours
- Heater at cylinder 3 warm long after switch-off
- Engine warning lamp, depending on manufacturer
- Likely causes
- LikelyChannel 3 output stage failed conducting
- PossibleCylinder 3 control wire shorted to a positive feed
- RareHeater supply relay contacts welded
- 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: €60 – €500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.