On CIS-Motronic systems, the power stage is a separate component mounted near the ignition coil. On later systems, the power stage is integrated into the coil pack.
Removal & Installation
- Unplug the wiring harness connector from the power stage.
- Remove the ignition coil.
- Remove the power stage from the ignition coil.
- Install the power stage to the ignition coil. Be careful not to overtighten the fasteners.
- Install the ignition coil.
- Plug the wiring harness connector into the socket on the power stage.
- Install the connectors on the ignition coil.
This test confirms that the ECM is sending an activation signal to the power stage for charging the ignition coil.
This test requires the use of a LED test light. Do NOT use an incandescent test light; the current required to illuminate the lamp can damage the ECM.
This test is dependant on the Hall sensor/camshaft sensor in the distributor functioning properly. Make sure it is operating properly before performing this procedure.
- Remove the fuel pump fuse to prevent the cylinders from filling with fuel while the engine is being cranked.
- Remove the harness connector from the power stage.
- Using an LED test light, connect the leads to terminal 2 and terminal 3.
- Turn the ignition switch ON and crank the engine.
- While the engine is cranking, the LED test light should flash. This indicates that a signal is being sent from the Hall sensor/camshaft position sensor to the power stage.
- If the LED does not flash, and the Hall sensor/camshaft sensor in the distributor is functioning properly, replace the power stage. If replacement of the power stage does not allow the LED test light to flash, the ECM may be faulty.
- Plug in the power stage connector.