P23D7Cylinder 2 Fuel Heater Control Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- For P23D7 the module reads the cylinder 2 heater control line as low, which on these power circuits nearly always means a path to ground: a chafed wire, a heater element shorted to its body, or fuel or water bridging the connector pins. The short draws more than the channel is meant to carry, so the heater unit protects itself; Bosch mentions reverse-voltage and internal overtemperature protection as well as short detection per circuit. In practice the heater on cylinder 2 is switched off and that cylinder starts cold while cylinders 1, 3 and 4 still get warm fuel; a blown heater fuse is possible. No manufacturer documents P23D7 publicly; CARB demands circuit checks on this output. High and open on cylinder 2: P23D6, P23D5; cylinder 1 equivalent: P23D3.
- What you may notice
- Rough cold start on one cylinder
- Fuel heater fuse blown
- Engine warning lamp, depending on manufacturer
- Likely causes
- LikelyCylinder 2 heater wire chafed through to ground
- PossibleHeating element at cylinder 2 shorted to its housing
- PossibleFuel or water bridging pins in the cylinder 2 heater plug
- 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.