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 3 is not lasting as long as it should. Think of it like a sparkler that goes out too quickly.
The engine control module (ECM) monitors the spark duration in each cylinder. If the spark in cylinder 3 is too short, it triggers this code.
P1303 indicates that the ignition spark duration for cylinder 3 is shorter than expected. This can affect engine performance and efficiency as the combustion process may not be completed properly.
• Engine misfires
• Rough idling
• Reduced fuel efficiency
• Faulty ignition coil
• Worn or fouled spark plug
• Damaged ignition wires or connectors
ECM: Engine Control Module
Ignition Coil: A component that converts battery voltage into the high voltage needed to create a spark at the spark plug.
• Use an OBD-II scanner to confirm the code.
• Inspect the ignition coil for cylinder 3 for damage.
• Check the spark plug in cylinder 3 for wear or fouling.
• Replace the ignition coil for cylinder 3 if faulty.
• Replace or clean the spark plug in cylinder 3.
• Repair or replace damaged ignition wires or connectors.
• OBD-II scanner
• Spark plug socket
• Multimeter
$100 - $300
Moderate
• BMW 3 Series
• Volkswagen Jetta
• Ford Focus
• Regularly replace spark plugs as per maintenance schedule.
• Inspect ignition components during routine service.
• Use high-quality fuel to prevent deposits.
Engine Performance
• Do not ignore the check engine light.
• Have your vehicle inspected by a professional if unsure.
Check with the vehicle manufacturer for warranty coverage on ignition components.
This code is often associated with ignition system issues and is more common in older vehicles with high mileage.
Moderate – It should be addressed soon to prevent further engine issues.
Driving with a misfire can cause damage to the catalytic converter and increase emissions.
• Engine running
• Vehicle at operating temperature
The ignition coil and spark plug for cylinder 3 are located on the engine, typically on the side or top depending on the engine layout.
Q: Can I drive with a P1303 code?
A: It's not recommended to drive for long with this code as it can lead to further engine damage.
Q: How can I prevent this issue?
A: Regular maintenance of the ignition system and using quality fuel can help prevent this issue.
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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.