P109C Possible Causes
- Faulty fuel pressure switching valve
- Fuel pressure switching valve circuit open or shorted
- Poor electrical connection in fuel pressure switching valve circuit
- Faulty F/PMP VSV relay
- Faulty engine control module (ECM)
Possible Symptoms
Engine light on (or engine warning light soon to come on)
P109C Meaning
A flexible fuel vehicle (FFV) can operate with fuel containing a high concentration of ethyl alcohol.
This FFV uses a fuel pressure switching system that changes fuel pressure to low or high using a fuel pressure switching valve.
The code is stored when a malfunction is detected in the fuel pressure switching valve circuit. If the fuel pressure switching valve circuit voltage differs from the voltage commanded by the engine control module (ECM), the ECM determines that the fuel pressure switching valve circuit is open or shorted and stores a DTC.