Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
7. An ignition coil, boots, or spark plugs may misfire only when moisture is present. Although difficult to test on this engine, selectively wetting down parts of the system and monitoring for misfire may isolate an intermittent condition. If moisture is present in the spark plug/ignition coil cavity of the cam cover, inspect the perimeter seal for damage. Repair any tears in the perimeter seal with an RTV sealant.
8. The J 26792 Spark Tester (ST 125) places a higher load on the secondary ignition than a normal spark plug.
13. Use the correct adaptor harness when connecting the Ignition Module Tester. Using an adaptor harness for a different engine application will result in incorrect tool operation.
The green Power LED should come on any time the ignition module tester is connected and the ignition switch is in the run position. This LED indicates that J 43298 Ignition Module Tester is receiving adequate power and ground to perform the test. The Test button is used as an LED check for the 4 red LEDs. In order to use this function, connect the tool, turn the ignition switch to run, then momentarily press the Test button. All 4 red LEDs should come on brightly. Then crank the vehicle. If the 4 red LEDs flash, this confirms proper operation of the primary ignition system, including the PCM, the wiring, the connections, and the ignition control module (ICM). The ignition module tester may get hot during actual testing. This is because the tester is attempting to simulate the load of the ignition coils primary windings.
If the LEDs flash, the module output drivers are operating. If one or more LEDs are inoperative, and no individual IC Circuit (DTC P0351-P0358) Group, or IC Circuit Group (DTC P1359 and/or P1360) DTCs are set, replace the module.
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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.