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 the car has detected a problem with the fuel injector for the first cylinder. It's like a tiny hose that sprays fuel into the engine, and the computer thinks it's getting too much power.
The P31C1 code indicates that the electrical circuit for the high-pressure fuel injector on cylinder 1 is experiencing higher than expected voltage.
P31C1 is triggered when the Engine Control Module (ECM) detects that the high side circuit of the high-pressure injector for cylinder 1 is above the expected voltage threshold. This could be due to a short circuit, faulty wiring, or a malfunctioning injector.
• Engine misfire
• Poor fuel economy
• Check engine light on
• Faulty injector
• Short circuit in wiring
• Faulty ECM
Injector: A device that sprays fuel into the engine's cylinders.
ECM: Engine Control Module, the computer that controls engine functions.
• Use an OBD-II scanner to confirm the code.
• Inspect the wiring and connectors for cylinder 1 injector.
• Test the injector for proper operation.
• Replace faulty injector.
• Repair or replace damaged wiring.
• Reprogram or replace the ECM if necessary.
• OBD-II scanner
• Multimeter
• Basic hand tools
$200 - $600
Moderate
• Toyota Camry
• Ford F-150
• Chevrolet Silverado
• Regular maintenance checks
• Ensure proper fuel quality
• Inspect wiring periodically
Engine Performance
• Avoid driving long distances until repaired.
• Have a professional diagnose the issue promptly.
Check with the vehicle manufacturer for warranty coverage on injectors.
This code has been associated with injector circuit issues in vehicles with direct injection systems.
Moderate – should be addressed soon to prevent engine damage.
Driving with this code may lead to increased emissions and potential engine damage.
• Engine running
• Warm engine temperature
The injector is located on the engine, near the cylinder head.
Q: Can I drive my car with a P31C1 code?
A: It's not recommended as it can lead to further engine damage and poor performance.
Q: How serious is a P31C1 code?
A: It's moderately serious and should be addressed soon to avoid engine issues.
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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.