Ignition Control Module: Testing and Inspection

Ignition Coil With Power Output Stage:

It is not necessary to test the power output stages unless there is no spark from one of the ignition coils, or spark is intermittent. If there is no spark from either or both ignition coils, check engine speed sensor and crankshaft position (reference) sensor first. If both of these sensors check out OK, then proceed with power output stage check.

1. Disconnect harness connector from power output stage on BOTH ignition coils.

RIGHT SIDE POWER STAGE AND COIL

2. Connect DVM between terminals #1 and #3 of harness connector. Set to 20 volt range.

3. Turn ignition ON and note voltage.

^ Should be battery voltage.

If not, check for:

a. Open or grounded circuit between right power stage harness connector terminal #1 and terminal 15 of ignition switch.
b. Open circuit between power stage harness connector terminal #3 and engine ground.

Repair as necessary.

4. Connect LED test light between terminals #2 and #3 of harness connector.

5. Crank engine and observe test light.

^ LED should flash (trigger signal from ECM).

If not, check for:

a. Open or grounded circuit between ECM terminal 1 and right ignition coil power stage harness connector terminal #2.
b. Open circuit between power output stage harness connector terminal #3 and engine ground.

Repair as necessary.

If no wiring problems are found and LED still does not flash in step 4, then the ECM is faulty (no ignition trigger signal from ECM).

If LED does flash and there is no spark, check ignition coil.

If ignition coil checks out OK and there is still no spark, replace power output stage.

LEFT SIDE POWER STAGE AND COIL

The test procedure for the left side power stage is identical to that for the right side power stage, except that terminal #2 of the left side power stage is connected to ECM terminal 20.