What does it mean?
The cold start fuel injection circuit is a driver output that the control module pulls to ground in order to energise the cold start injector or the cold start injection stage while the engine warms up. With the device switched off, the module expects that line to sit close to battery voltage and to fall only when it commands it.
P02FC is stored when the module measures a voltage below its low threshold at a time when the circuit should be de-energised, which is the classic signature of a short to ground or of an internally shorted solenoid. To protect its output transistor the module usually disables the circuit once the fault is confirmed, so the cold start enrichment stops taking place. Everything about this code points to the wiring or the solenoid, not to fuel pressure or mixture control.
Symptoms
- Difficult cold starting and extended cranking on the first start of the day
- Unsteady idle and misfire-like roughness during warm-up
- Smell of fuel or visible exhaust smoke shortly after a cold start
- MIL on with the code set, frequently on the very first cold start
- Blown fuse for the circuit on some vehicles
- Driving quality returns to normal once the engine is hot
Likely causes
- Control wire rubbed through against the engine, body or a bracket and grounding out
- Internally shorted cold start injector solenoid with abnormally low winding resistance
- Water or coolant intrusion in the connector bridging the control pin to a ground pin
- Harness crushed or pinched under a clip or bracket after previous service work
- Insulation damaged by heat where the wiring runs close to the exhaust or turbocharger
- Shorted module output driver, confirmed only after the device has been unplugged and the harness cleared
How to fix it
- Confirm the conditions in the freeze frame data and note whether the code sets on every cold start or only occasionally
- Disconnect the device and check whether the low voltage is still present at the module side; if it is, the fault is in the harness
- Measure the solenoid resistance and compare with specification, since an unusually low value proves an internal short
- Follow the control wire along its whole route and inspect chafe points, clips and the sections nearest to heat sources
- With both ends disconnected, measure resistance from the control wire to ground; a low reading confirms a grounded wire
- Repair the damaged section with a soldered and heat-shrunk joint rather than tape, then re-check the circuit
- Clear the code and verify over several cold starts while watching the activation in live data