Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This means that the car's computer has detected a problem with the electrical signal that controls one of the spark plugs. It's like when a light switch is stuck in the 'on' position.
The P031C code indicates that the voltage in the ignition control circuit for cylinder C is higher than expected.
The P031C code is triggered when the Engine Control Module (ECM) detects a high voltage condition in the ignition control circuit for cylinder C. This could be due to a short circuit, a faulty ignition coil, or a problem with the wiring or connectors.
• Check Engine Light is on
• Engine misfires
• Poor engine performance
• Faulty ignition coil
• Short circuit in the ignition control circuit
• Damaged or corroded wiring or connectors
ECM: Engine Control Module
OBD-II: On-Board Diagnostics, Second Generation
• Use an OBD-II scanner to verify the code.
• Inspect the ignition coil and wiring for damage.
• Test the ignition coil for proper operation.
• Replace the faulty ignition coil.
• Repair or replace damaged wiring or connectors.
• Clear the code and test drive the vehicle.
• OBD-II scanner
• Multimeter
• Basic hand tools
$100 - $300
Moderate
• Ford F-150
• Chevrolet Silverado
• Toyota Camry
• Regularly inspect ignition components.
• Keep electrical connections clean and secure.
• Use high-quality ignition parts.
Engine Performance
• Do not ignore the Check Engine Light.
• Have the vehicle inspected by a professional if unsure.
• Regular maintenance can prevent such issues.
Check your vehicle's warranty for coverage on ignition components.
This code is commonly associated with ignition coil failures, especially in older vehicles.
Moderate – Addressing this issue promptly can prevent further engine damage.
Driving with a misfiring engine can lead to increased emissions and potential engine damage.
• Engine running
• Code present in the ECM
The ignition coil is typically located on top of the engine, near the spark plugs.
Q: Can I drive with a P031C code?
A: It's not recommended to drive for extended periods with this code, as it can cause engine damage.
Q: How can I prevent ignition coil issues?
A: Regular maintenance and using quality parts can help prevent ignition coil issues.
High-End · Full-system diagnostics
A full-system bidirectional platform aimed at advanced DIY users and professional diagnostic workflows.
Network faults often require full-system access instead of a generic code reader alone.
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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.
View on AmazonThese are optional diagnostic tools, not guaranteed fixes. As an Amazon Associate I earn from qualifying purchases.
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.
View options on Amazon
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.