Symptoms and Severity
Excessive fuel pressure can lead to various driving issues, as well as internal damage to the engine and catalytic converter. For this reason, a P2294 code should be classified as severe.
Symptoms of a P2294 code may include:
- Delayed starting
- Black smoke from the exhaust system
- Reduced fuel efficiency
- Engine driveability codes may also accompany a P2294
Causes
Potential causes for this code being set are as follows:
- Shorted or open wiring or connectors in the fuel pressure regulator control circuit
- Faulty fuel pressure regulator
- Faulty fuel rail pressure sensor
- Incorrect PCM or PCM programming error
Diagnostic and Repair Procedures
A diagnostic scanner, digital volt/ohmmeter (DVOM), appropriate fuel pressure gauge, and a reliable vehicle information source (such as All Data DIY) will be needed to diagnose a P2294 code.
NOTE: Be extremely careful when connecting a manual pressure gauge. High-pressure fuel coming into contact with hot surfaces or an open spark can ignite and cause a dangerous fire.
I normally start with a visual inspection of the system’s wiring and connectors; focusing my attention on the harnesses and connectors on top of the engine. The heat associated with this area makes it popular with pests in cold climates. These pests can damage (chew) the system’s wiring and connectors.
Connecting the scanner to the vehicle’s diagnostic port and retrieving stored codes and freeze frame data would be my next task. I write down this information as it may be useful during the diagnostic process. Now, I would clear the codes and test the vehicle if possible.
If the code immediately resets, check the voltage and ground at the fuel pressure regulator. If no voltage is found, test the power relays and fuses following the wiring diagram derived from the vehicle information source. If there is no ground, follow the wiring diagram to locate the appropriate ground(s) for the fuel pressure regulator control system and ensure all are secure.
If there is voltage and ground at the fuel pressure regulator control, obtain the fuel pressure specifications from your vehicle information source and test the fuel system pressure using the fuel pressure gauge. Carefully follow the manufacturer’s recommendations for connecting the fuel pressure gauge. Observe the fuel system data using the scanner while visually monitoring the manual fuel pressure with the fuel gauge. If the fuel pressure reflected on the scanner data display does not match the actual fuel pressure, suspect a faulty fuel pressure sensor.
Fluctuations in actual fuel pressure should occur with variations in the fuel pressure regulator control voltage. If not, suspect that the fuel pressure regulator is faulty, there is an open or short circuit in one of the fuel pressure regulator control circuits, or the PCM is faulty.
Follow the manufacturer’s recommendations for testing the electronic fuel pressure regulator and individual fuel pressure regulator control circuits with the DVOM. Disconnect controllers from the circuit before testing with the DVOM to avoid damaging control modules.
Additional Diagnostic Notes:
The fuel rail and associated components may be under high pressure. Be cautious when removing the fuel pressure sensor or fuel pressure regulator
Turn the ignition switch to OFF to connect/disconnect the fuel pressure gauge