What does it mean?
P1555 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Cylinder 5 Injector Circuit Range/Performance .
Symptoms
- Check engine light on, frequently together with a cylinder 5 misfire code
- Uneven running and misfire that is worst at idle and on light load
- Loss of power and a stumble when pulling away
- Long cranking time before the engine fires
- Higher fuel use and an unburnt fuel smell at the tailpipe
- Noticeable vibration through the floor at idle
Likely causes
- Injector solenoid winding that has drifted out of specification or is partially shorted internally
- Corroded injector connector, often after oil or coolant has crept along the wiring
- Harness chafing against the cylinder head cover or an intake runner on the cylinder 5 side
- Loose or broken terminal inside the injector loom connector
- Restricted or leaking injector that changes the electrical response the PCM measures
- Injector correction values not written into the module after a replacement on common rail systems
- Damaged injector output stage inside the PCM
How to fix it
- Record the freeze frame and check the misfire and injector balance data for cylinder 5
- Verify that the injector is being pulsed by the PCM using a test light or a scope at the connector
- Measure the injector resistance and compare it against the other injectors on the engine
- Move the suspect injector to another cylinder and see whether the fault moves with it
- Inspect the harness and connector at cylinder 5 for oil contamination, chafing and loose terminals
- Fit or clean the injector as required and program the calibration code when the system uses one
- Repair damaged wiring, clear the code and confirm even cylinder contribution on a road test