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 car's computer noticed that the spark in cylinder 4 didn't last as long as it should. It's like when you try to light a firework, but the spark goes out too quickly.
The engine control module (ECM) monitors the duration of the spark in each cylinder. If the spark in cylinder 4 is shorter than expected, it triggers this code.
P1304 indicates that the ignition system for cylinder 4 is not providing a spark of sufficient duration. This can lead to misfires and reduced engine performance. The ECM uses data from various sensors to determine the expected spark duration and triggers this code when the actual duration is below the threshold.
• Check engine light on
• Engine misfire
• Rough idling
• Faulty ignition coil
• Worn or damaged spark plug
• Faulty ignition control module
ECM: Engine Control Module
OBD-II: On-Board Diagnostics II
• Use an OBD-II scanner to confirm the code.
• Inspect the ignition coil for cylinder 4.
• Check the spark plug for cylinder 4 for wear or damage.
• Replace the ignition coil for cylinder 4.
• Replace the spark plug for cylinder 4.
• Check and repair any wiring issues related to the ignition system.
• OBD-II scanner
• Socket set
• Multimeter
$100 - $300
Moderate
• Toyota Camry
• Honda Accord
• Ford F-150
• Regularly replace spark plugs.
• Inspect ignition coils during routine maintenance.
• Use high-quality fuel to prevent deposits.
Engine Performance
• Do not ignore the check engine light.
• Have the vehicle inspected by a professional mechanic.
• Avoid driving the vehicle until the issue is resolved to prevent further damage.
Check if the ignition system components are covered under the vehicle's powertrain warranty.
P1304 has been associated with ignition system failures, especially in vehicles with high mileage or poor maintenance history.
Moderate – It should be addressed soon to prevent engine damage.
Driving with a misfiring engine can lead to increased emissions, which may violate local emissions laws.
• Engine at operating temperature
• Under load conditions
Cylinder 4 is typically located on the engine block, and its position can vary depending on the engine layout.
Q: Can I drive with code P1304?
A: It's not recommended to drive with this code as it can lead to further engine damage.
Q: How can I clear the P1304 code?
A: After repairing the issue, use an OBD-II scanner to clear the code.
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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.