Symptoms and Severity
Since excessive fuel pressure can damage the internal engine and catalytic converter and lead to various driving issues, a P2296 code should be classified as severe.
Symptoms of a P2296 code may include:
- Engine misfire codes and idle control codes may also accompany a P2296
- Reduced fuel efficiency
- Delayed starting when the engine is cold
- Black smoke from the exhaust system
Causes
Potential causes for this code definition include:
- Faulty fuel pressure sensor
- Faulty fuel pressure regulator
- Shorted or open wiring or connectors in the fuel pressure regulator control circuit
- Incorrect PCM or PCM programming error
Diagnostic and Repair Procedures
Diagnosing a P2296 code will require access to a diagnostic scanner, a digital volt/ohmmeter (DVOM), an appropriate fuel pressure gauge, and a reliable vehicle information source (such as All Data DIY).
NOTE: Extreme caution must be exercised when using a manual pressure gauge. High-pressure fuel coming into contact with hot surfaces or an open spark could ignite and cause a fire.
A visual inspection of the system’s wiring and connectors, focusing on the harnesses and connectors on top of the engine, has been successful for me in the past. It seems that the hot area of the upper engine is popular with pests, especially in cold climates. Unfortunately, pests often repeatedly chew on the system’s wiring and connectors.
Next, I would connect the scanner to the vehicle’s diagnostic port and retrieve stored codes and freeze frame data. Writing down this information can be helpful if the diagnostic process becomes prolonged. Clear the codes and test the vehicle if the engine starts.
Check for proper voltage level and battery ground at the fuel pressure regulator if the code resets. If no voltage is detected at the fuel pressure regulator connector, test the power relays and fuses by following the appropriate wiring diagram from the vehicle information source. If there is no ground, the wiring diagram can help you locate the ground points of the fuel pressure regulator control system and ensure they are secure.
Proper voltage and ground circuits found at the fuel pressure regulator control connector would lead me to obtain fuel pressure specifications from the vehicle information source and test the fuel system pressure using the fuel pressure gauge. Remember to follow the manufacturer’s recommendations for using the fuel pressure gauge.
Monitor the manual fuel pressure with the fuel gauge while using the scanner to observe the fuel system data. A faulty fuel pressure sensor may be the cause of your problems if the fuel pressure level reflected on the scanner does not match the actual fuel pressure. Variations in the fuel pressure regulator control voltage should reflect fluctuations in the actual fuel rail pressure. Otherwise, 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.
To test the electronic fuel pressure regulator and individual fuel pressure regulator control circuits, use the DVOM and follow the manufacturer’s recommendations. Disconnect controllers from the circuit before testing circuit resistance and continuity with the DVOM.
Additional Diagnostic Notes:
The fuel rail and associated components are under high pressure. Be cautious when removing the fuel pressure sensor or fuel pressure regulator.
Fuel pressure tests should be performed with the ignition switch in the key on engine off (KOEO) position