Ignition System No Start Test

Note: This no-start test checks the camshaft position sensor and crankshaft position sensor.

Theory Of Operation

The powertrain control module (PCM) supplies 8 volts to the camshaft position sensor and crankshaft position sensor through one circuit. If the 8-Volt supply circuit shorts to ground, neither sensor will produce a signal (output voltage to the PCM).

When the ignition key is turned and left in the On position, the PCM automatically energizes the auto shutdown (ASD) relay. However, the controller deenergizes the relay within one second because it has not received a crankshaft position sensor signal indicating engine rotation.

During cranking, the ASD relay will not energize until the PCM receives a crankshaft position sensor signal. Secondly, the ASD relay remains energized only if the controller senses a camshaft position sensor signal immediately after detecting the crankshaft position sensor signal.

Test Procedure

1. Check battery voltage.
^ If battery voltage is not at least 12.66 volts, charge battery and repair charging system if necessary, prior to performing this test.

2. Disconnect the harness connector from the coil pack.

3. Connect a test light between the B + (battery voltage) terminal of the coil electrical connector and ground. (The wire for the B + terminal is dark green with a black tracer.)

4. Turn the ignition key to the ON position. The test light should flash ON and then OFF. Do not turn the Key to OFF position, leave it in the ON position.

^ If the test light flashes momentarily, the PCM grounded the Auto Shutdown (ASD) relay. Proceed to step 5.

^ If the test light did not flash, the ASD relay did not energize. The cause is either the relay or one of the relay circuits. Use a scan tool to test the ASD relay and circuits. Refer to the appropriate Powertrain Diagnostics Procedures, and wiring diagrams section for circuit information.

5. Crank the engine. (If the key was placed in the OFF position after step 4, place the key in the ON position before cranking. Wait for the test light to flash once, then crank the engine.)

If the test light momentarily flashes during cranking; the PCM is not receiving a camshaft position sensor signal.

^ Use a scan tool to test the camshaft position sensor and sensor circuits. Refer to the appropriate Powertrain Diagnostics Procedure Manual. Refer to the wiring diagrams section for circuit information.

If the test light did not flash during cranking;

1. Unplug the camshaft position sensor connector.
2. Turn the ignition key to the OFF position.
3. Turn the key to the On position, wait for the test light to momentarily flash once, then crank the engine.

^ If the test light momentarily flashes, the camshaft position sensor is shorted and must be replaced.

^ If the light did not flash, the cause of the no-start is in either the crankshaft position sensor/camshaft position sensor 8-Volt supply circuit, or the crank- shaft position sensor 5-Volt output or ground circuits. Use a scan tool to test the crankshaft position sensor and the sensor circuits. Refer to the appropriate Powertrain Diagnostics Procedure Manual. Refer to the wiring diagrams section for circuit information.