GASKET 3J5552 - Caterpillar

The Electronic Control Module (ECM) provides extensive diagnostics for the ignition system. A diagnostic code is generated if a problem with the primary circuit or the secondary circuit is detected. For instructions on troubleshooting the electrical circuit, refer to the Troubleshooting Manual.If an ignition transformer is suspect, use the following procedure to check the transformer:
Ignition systems can cause electrical shocks. Avoid contacting the ignition system components and wiring.Do not attempt to remove the valve covers when the engine is operating. The transformers are grounded to the valve covers. Personal injury or death may result and the ignition system will be damaged if the valve covers are removed during engine operation. The engine will not operate without the valve covers.
Turn the engine control switch to the OFF/RESET position. Switch the circuit breaker for the engine OFF.
Remove the valve cover of the suspect cylinder.
Pulling on the wiring harness may break the wires. Do not pull on the wiring harness.
Disconnect the ignition harness from the transformer. Remove the transformer from the engine.
Illustration 1 g01457623
(1) Screw for the ground spring (2) Ground spring (3) Adapter (4) Terminal for the spark plug (5) Insulator (6) O-ring seal
Inspect the body of the transformer and ground spring (2) for corrosion and/or damage. Verify that screws (1) for the ground spring are secure.Note: Punch through is caused by misfire in the engine that does not generate a diagnostic code.
Check the insulator near adapter (3) for signs of punch through (pin holes) and/or arcing.
Inspect O-ring seal (6) inside the insulator for damage.
Remove O-ring seal (6). Inspect terminal (4) inside the insulator for looseness, corrosion, and/or damage. Insert an extra spark plug into the transformer and check for spring pressure of terminal (4) .
The insulator can be scratched and damaged with a wire brush. Do not use a wire brush on the insulator.
Clean any deposits from the inside of the insulator. Use a 6V-7093 Brush with isopropyl alcohol.
Measure the primary circuit by checking the voltage of the diode.
Set the multimeter to the diode scale. Connect the multimeter leads to the terminals of the 2-pin connector. The polarity of the leads is not important. Measure the voltage between the terminals. Record the measurement.
Reverse the multimeter leads. Measure the voltage bet