JB1 VISUAL INSPECTION

Visually inspect the engine compartment to make sure all the coils are correctly and securely connected.
Examine all the wiring harnesses and connectors for damaged, burned, or overheated insulation, and loose or broken conditions.
Make sure the vehicle battery is in good condition and all accessories are turned off.

Is a concern indicated?

Yes	No
REPAIR as necessary. Clear the PCM DTCs. REPEAT the self-test.	For DTC P0300 or symptoms without DTCs, GO to JB3. For all others, GO to JB2.

JB2 CHECK FOR SPARK AT THE CYLINDER INDICATED

NOTE: Do not disconnect any COP while the engine is running, damage to the COP or PCM may occur.

Ignition OFF.
Disconnect the suspect fuel injector connector for the indicated cylinder.
Disconnect the suspect COP from the spark plug for the indicated cylinder.
Connect the Adjustable Ignition Spark Tester THX458 or equivalent to a COP.
Start the engine using the engine running diagnostic mode. Refer to DIAGNOSTIC MODES .
Observe the spark tester.

Is a bluish-white spark present?

Yes	No
GO to JB4.	INSPECT the COP boot on the missing cylinder. REPAIR as necessary. INSPECT the spark plug on the missing cylinder. MEASURE the resistance of the spark plug. INSTALL a new spark plug if the resistance is lower than 2, 000 ohms or higher than 12, 000 ohms. GO to PINPOINT TEST JF .

JB3 CHECK FOR SPARK AT ALL CYLINDERS
NOTE: Do not disconnect any COP while the engine is running, damage to the COP or PCM may occur.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

Test Procedure