TDC Sensor

To test the Top Dead Center (TDC) Sensor located in the distributor, proceed as follows.

System Schematic:

OSCILLOSCOPE TESTING PROCEDURE:

1. Connect test leads from the oscilloscope to the #4 terminal of the sensor connector and run the engine at idle speed.

Scope Test Waveform--single Rotation Of The Distributor:

Check the waveform and compare it to the diagram shown.

VOLTAGE TESTING PROCEDURE:

1. Connect a voltmeter between terminal 2 and 4 of the crank angle sensor connector.
Terminal 4: Top Dead Center (TDC) signal
Terminal 2: Sensor ground

2. Measure the output voltage of the terminals while cranking the engine.
Standard Approximate Value

Terminal 4: 2.0 - 2.5v


3. When the voltage is abnormal, check the sensor power and ground circuits.

Refer to COMPUTERIZED ENGINE CONTROLS for further information.