What does it mean?
P1207 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: FICM PWM Signal To PCM Circuit Malfunction .
Symptoms
- Hard starting and extended cranking, noticeably worse when cold
- Rough running, misfire and clear loss of power
- Sudden stalling, with the engine restarting after a wait
- White or grey smoke on start-up on diesel applications
- Check engine lamp on, frequently together with injector or module voltage codes
Likely causes
- Low or unstable supply voltage to the injection control module, which distorts the signal it produces
- Open, shorted or chafed PWM signal wire running between the two modules
- Corroded or water damaged module connector, a frequent problem where the module is mounted in the engine bay
- Poor shared ground causing a signal offset the PCM rejects
- Internal failure of the module output stage
- Damaged input circuit inside the PCM
How to fix it
- Read module supply voltage on the scan tool during cranking and at idle before touching any wiring
- Unplug, dry and inspect both module connectors for corrosion and pushed-back terminals
- Voltage drop test the module power and ground circuits under load
- Check the signal wire between the two modules for continuity and for shorts to ground or battery
- Wiggle the harness while watching the signal for dropouts
- Replace the injection control module only once supply, ground and wiring are proven good
- Treat a PCM input failure as the last option, after every external cause is eliminated