P23DD — Cylinder 4 Fuel Heater Control Circuit Open
Per-cylinder fuel heaters (used on some heavy-duty diesels for cold-start atomisation) on cylinder 4 have an open control circuit.
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
- Fuel heater cyl 4
Possible causes to check
These are possible checks, not a ranked diagnosis. Follow the vehicle manufacturer's test procedure before replacing parts.
- Open in heater or wiring
- Pin pushed back out of connector body
- Cracked solder joint inside the module or sensor
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
Related codes
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.