Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
The car's computer is saying there's a problem with the part that makes the spark for cylinder number 7. It's like when a spark plug doesn't work right, and the car might not run smoothly.
This code indicates that the ignition coil circuit for cylinder 7 is experiencing a high resistance or no impedance, which affects the spark generation.
The ignition coil is responsible for converting the battery's voltage into a spark that ignites the fuel in the engine's cylinder. Code P3318 is set when the Powertrain Control Module (PCM) detects that the resistance in the ignition coil circuit for cylinder 7 is higher than expected or is open, indicating a potential fault in the wiring, connector, or the coil itself.
• Engine misfire
• Poor fuel economy
• Check Engine Light illuminated
• Faulty ignition coil for cylinder 7
• Damaged or corroded wiring/connectors
• Faulty PCM
PCM: Powertrain Control Module
OBD-II: On-Board Diagnostics II
• Use an OBD-II scanner to confirm the code.
• Inspect the ignition coil and wiring for cylinder 7.
• Test the ignition coil for proper resistance.
• Replace the ignition coil for cylinder 7.
• Repair or replace damaged wiring/connectors.
• Reprogram or replace the PCM if necessary.
• OBD-II scanner
• Multimeter
• Socket set
$150 - $400
Moderate
• Ford F-150
• Chevrolet Silverado
• Toyota Camry
• Regular maintenance checks
• Replace spark plugs and coils at recommended intervals
• Keep electrical connections clean and secure
Engine Performance
• Avoid driving with this issue for long periods.
• Have a professional mechanic inspect the vehicle.
Check with your vehicle manufacturer for warranty coverage on ignition components.
This code is commonly associated with ignition coil failures, particularly in vehicles with high mileage.
Moderate – Should be addressed soon to avoid further engine damage.
Driving with a misfiring engine can lead to increased emissions and potential safety hazards.
• Engine at operating temperature
• Vehicle in park or neutral
The ignition coil for cylinder 7 is typically located on the engine block, near the spark plug for cylinder 7.
Q: Can I drive my car with a P3318 code?
A: It's not recommended to drive for long periods with this code, as it can lead to further engine damage and poor performance.
Q: How do I know if my ignition coil is bad?
A: Symptoms of a bad ignition coil include engine misfires, rough idling, and a decrease in fuel efficiency.
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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.
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.