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 a problem with the injector for cylinder 4. It's like a squirt gun that sprays fuel into the engine, and the computer thinks it's not working right.
The code indicates an issue with the electrical circuit controlling the fuel injector for cylinder 4. The 'low side' refers to the part of the circuit that connects to ground, and 'high' means there is too much voltage or resistance.
P318C is set when the Engine Control Module (ECM) detects a high voltage condition in the low side circuit of the fuel injector for cylinder 4. This could be due to a short to power, high resistance, or an open circuit in the wiring or connector.
• Engine misfire
• Decreased fuel efficiency
• Check Engine Light on
• Faulty injector for cylinder 4
• Wiring issues such as a short or open circuit
• Bad connection at the injector or ECM
ECM: Engine Control Module
Injector: A device that sprays fuel into the engine
• Check for any loose or corroded connections at the injector and ECM.
• Inspect the wiring harness for damage or shorts.
• Test the injector for proper resistance and operation.
• Repair or replace damaged wiring or connectors.
• Replace the faulty injector.
• Clear the code and test drive to ensure the issue is resolved.
• Multimeter
• OBD-II scanner
• Basic hand tools
$150 - $500
Moderate
• Ford F-150
• Chevrolet Silverado
• Toyota Camry
• Regularly inspect and maintain the fuel system.
• Keep electrical connections clean and secure.
• Use quality fuel to prevent injector clogging.
Engine Performance
• Do not ignore the check engine light; get it checked soon.
• If you notice poor engine performance, have it diagnosed by a professional.
Injector-related repairs may be covered under the powertrain warranty. Check with your manufacturer.
This code is relatively uncommon and typically associated with specific wiring or injector issues.
Moderate – Should be addressed soon to prevent further engine performance issues.
Driving with a misfiring engine can lead to increased emissions and potential engine damage.
• Engine at operating temperature
• Vehicle in a safe location for testing
The injector for cylinder 4 is located on the engine block, usually under the intake manifold.
Q: Can I drive my car with this code?
A: It's not recommended to drive for long with this code as it can cause engine damage.
Q: How can I prevent this issue?
A: Regular maintenance and using quality fuel can help prevent injector issues.
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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.