Symptoms

- Engine Light ON (or Service Engine Soon Warning Light)

Possible Causes

- Ignition primary circuit is open or shorted - Ignition primary circuit poor electrical connection - Faulty power transistor unit built into ignition coil - Faulty ignition system condenser - Crankshaft position sensor circuit

When Detected

- When the ignition signal in the primary circuit is not sent to Engine Control Module (ECM) during engine cranking or running.

Description

The ignition signal from the Engine Control Module (ECM) is sent to and amplified by the power transistor. The power transistor turns on and off the ignition coil primary circuit. This on-off operation induces the proper high voltage in the coil secondary circuit.