What does it mean?
To fire the coil on the sixth ignition channel the module has to pull the control line low. P035F is set when the module issues that command but the line stays high, so the current it expects never flows. The usual causes are an open or resistive control path or battery voltage arriving on the line from elsewhere. Because the fault is limited to one channel, the shared coil supply and ground are normally healthy, and the search should concentrate on this channel's wire, its terminals and the coil input it feeds.
Symptoms
- Steady misfire with a rough idle and noticeable vibration
- MIL on and flashing when the engine is loaded
- Reduced power, hesitation and dull throttle response
- Hard starting, particularly when cold or damp
- Exhaust popping and a smell of unburnt fuel
- Increased fuel consumption
Likely causes
- High resistance connection or a partial break in the F channel control wire
- Corroded, loose or spread terminals in the coil or module connector
- Control line shorted to battery voltage through damaged insulation
- Open igniter input inside the sixth coil
- Poor ignition module ground so the driver cannot pull the line down
- Faulty module output stage, considered only after the wiring has been proven good
How to fix it
- Read the misfire counters and freeze frame data to pin down the cylinder and the conditions
- Inspect and probe the connector terminals at both ends of the circuit for tension and corrosion
- Measure the control line voltage with the ignition on and while cranking to confirm it stays high
- Perform continuity and voltage drop tests along the control wire
- Disconnect the module and test the line for a short to a permanently live circuit
- Check the coil supply, the ignition ground and the relevant fuse
- Repair the wiring or renew the coil, then clear the code and verify with a road test