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 there is a problem with the injector that puts fuel into cylinder number 4 of the engine. It is not getting enough power to work properly.
The code P31C6 indicates an issue with the electrical circuit that powers the high-pressure fuel injector for cylinder 4. The circuit is reading as having low voltage, which can affect the injector's performance.
The P31C6 code is triggered when the Engine Control Module (ECM) detects a low voltage condition in the high side circuit of the high-pressure injector for cylinder 4. This could be due to a wiring issue, a faulty injector, or a problem with the ECM itself. The high-pressure injector is crucial for delivering the correct amount of fuel into the combustion chamber at the right time, and any disruption in its operation can lead to engine performance issues.
• Engine misfire
• Poor fuel economy
• Check engine light on
• Faulty injector
• Wiring issues in the injector circuit
• 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 4 injector.
• Test the injector for proper operation.
• Repair or replace damaged wiring or connectors.
• Replace the faulty injector.
• Reprogram or replace the ECM if necessary.
• OBD-II scanner
• Multimeter
• Basic hand tools
$200 - $600
Moderate
• Vehicle 1
• Vehicle 2
• Vehicle 3
• Regular maintenance and inspection of fuel system components.
• Ensure proper electrical connections.
• Use quality fuel to avoid injector clogging.
Engine Performance
• Do not ignore the check engine light.
• Have the vehicle inspected by a professional if you notice performance issues.
Check with your vehicle manufacturer for warranty coverage on fuel injectors.
This code has been associated with injector circuit issues in various models, often due to wiring problems.
Moderate – This issue can lead to engine performance problems if not addressed.
Ignoring this issue can lead to increased emissions and potential engine damage.
• Engine running
• Under load conditions
The injector for cylinder 4 is located on the engine, near the intake manifold.
Q: What happens if I ignore this code?
A: Ignoring this code can lead to poor engine performance and increased emissions.
Q: Can I drive with this code?
A: It's possible to drive short distances, but it's recommended to fix the issue soon to avoid further damage.
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Universal · Digital multimeter
A solid entry-level multimeter for voltage, continuity, resistance, and basic electrical troubleshooting.
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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.