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 something is wrong with the part of the car that helps fuel get into the engine for cylinder number 8. It's like a straw that helps the car drink fuel, and there's an issue with the straw for that specific part of the engine.
This code indicates a problem with the electrical circuit that controls the high-pressure fuel injector for cylinder 8. The circuit is reading a voltage that's too high.
The P31CF code is triggered when the Engine Control Module (ECM) detects a high voltage condition in the high side circuit of the high-pressure fuel injector for cylinder 8. This could be due to a short to voltage or an open circuit condition.
• Check Engine Light is on
• Poor engine performance
• Engine misfire
• Faulty injector
• Wiring issues such as a short to voltage or open circuit
• Faulty ECM
ECM: Engine Control Module
Injector: A component that sprays fuel into the engine's cylinders
• Scan the vehicle for codes and freeze frame data.
• Inspect the wiring and connectors for cylinder 8 injector.
• Test the injector for proper resistance and operation.
• Repair or replace damaged wiring or connectors.
• Replace the faulty injector.
• Replace or reprogram the ECM if necessary.
• OBD-II scanner
• Multimeter
• Basic hand tools
$200 - $600
Moderate
• Chevrolet Silverado
• GMC Sierra
• Cadillac Escalade
• Regular maintenance and inspection of the fuel system.
• Ensure proper electrical connections.
• Use quality fuel to prevent injector clogging.
Engine Performance
• Do not ignore the Check Engine Light.
• Have the vehicle inspected by a professional mechanic.
• Avoid driving the vehicle if it shows severe symptoms.
Check with the vehicle manufacturer for specific warranty coverage related to the fuel system.
This code has been associated with vehicles using direct fuel injection systems, where high-pressure injectors are more common.
Moderate – Addressing this issue can prevent further engine damage and maintain performance.
Ignoring this code can lead to increased emissions and potential engine damage, which may not comply with emissions regulations.
• Engine running
• Warm engine temperature
The high-pressure injector for cylinder 8 is located on the engine, typically on the cylinder head.
Q: Can I drive my car with a P31CF code?
A: It's not recommended to drive with this code active, as it can lead to engine performance issues and potential damage.
Q: How do I reset the P31CF code?
A: After repairs, you can reset the code using an OBD-II scanner, but ensure the issue is fixed first.
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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.