Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means that the computer in your car has detected that the pressure in the fuel system is too low. It's like when you try to drink from a straw and there's not enough liquid coming through.
The engine control module (ECM) monitors the fuel rail pressure to ensure the engine is getting the right amount of fuel. If the pressure is too low, it sets this code.
P108A indicates a low voltage signal from the fuel rail pressure regulator circuit. This can result from an electrical issue, a faulty regulator, or a problem with the fuel supply system.
• Engine misfires or runs rough
• Poor fuel economy
• Check Engine Light is on
• Faulty fuel rail pressure regulator
• Wiring issues in the pressure regulator circuit
• Low fuel pressure due to a weak fuel pump
ECM: Engine Control Module
Fuel Rail: A pipe that delivers fuel to the engine's injectors
• Use an OBD-II scanner to confirm the code.
• Inspect the wiring and connectors for damage.
• Test the fuel rail pressure regulator for proper operation.
• Repair or replace damaged wiring or connectors.
• Replace the faulty fuel rail pressure regulator.
• Check and replace the fuel pump if necessary.
• OBD-II scanner
• Multimeter
• Fuel pressure gauge
$150 - $500
Moderate
• Ford F-150
• Chevrolet Silverado
• Dodge Ram 1500
• Regularly maintain the fuel system.
• Use high-quality fuel.
• Perform periodic fuel system checks.
Sensor Issue
• Have your vehicle inspected by a professional.
• Avoid driving with this code active to prevent further damage.
Check your vehicle's warranty for coverage on fuel system components.
This code has been associated with issues in vehicles with high mileage or poor maintenance history.
Moderate – Addressing this issue promptly can prevent further engine performance problems.
Driving with a fuel system issue can lead to engine damage or unsafe driving conditions.
• Engine at operating temperature
• Vehicle idling or under load
The fuel rail pressure regulator is typically located on or near the fuel rail in the engine compartment.
Q: Can I drive with a P108A code?
A: It's not recommended as it can lead to further engine issues.
Q: What happens if I ignore this code?
A: Ignoring it can result in poor engine performance and potential damage.
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Universal · Digital multimeter
A solid entry-level multimeter for voltage, continuity, resistance, and basic electrical troubleshooting.
Helpful for checking voltage drops, grounds, and basic circuit health when modules are not communicating.
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Universal · Wire connectors and repair kit
Useful when diagnosis points toward damaged wiring, corroded terminals, or connector repairs.
Useful if diagnosis points toward damaged connectors, wiring, or terminal repairs.
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Fitment Required · Vehicle-fitment part
Commonly relevant for misfire, ignition-efficiency, and some drivability-related repairs.
Misfire and ignition-related faults commonly involve spark plugs as part of the repair path.
Check the correct plug type, gap, and engine application for your vehicle.
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Fitment Required · Vehicle-fitment part
Relevant when the fault points toward ignition-coil performance or cylinder-specific ignition issues.
Some ignition faults involve coil performance or cylinder-specific coil problems.
Match the coil to your engine and confirm the failed component before ordering.
View options on AmazonThese parts may be related to this fault category, but a code by itself does not confirm exact fitment or guarantee that replacing a part will solve the problem.