Chart A-3

ENGINE CRANKS BUT WON'T RUN (Page 2 of 3)

Circuit Description: For timing of spark plug firing, a cam sensor "hall effect" switch is used. The cam sensor sends a signal (Sync-Pulse) to the ignition module when cylinder #1 is 25~ after top dead center on the compression stroke. This signal is used to start the correct sequence of coil firing and to enable sequential fuel injection. The engine will continue to run if the cam signal is lost while running, however, will not restart after shut down and a Code E041 will be stored. The crank sensor sends a signal to the ignition module and then to the ECM for reference rpm and crankshaft position. There are three windows in a disc (interruptor) which is mounted to the harmonic balancer. These windows pass by the sensor and as each window passes, the next coil is triggered.

Test Description: The following numbered steps correspond with the step numbers on the diagnostic chart.
8. Verifies ignition feed voltage at terminal "M" of the C(3)I modules. Less than battery voltage would be an indication of a CKT 639 fault.

9. The test light to 12 volts simulates a reference signal to the ECM which will result in an injector test light blink if the CKT 430, the ECM and the injector driver circuit are all OK.

10. If the Cam Sensor signal circuit terminal "A" is jumpered to the ground circuit terminal "B", the response will be an injector test light blink. This is a result of this artificial "Cam Signal" being transmitted through the C(3)I module to ECM terminal "A11" and the ECM activating the injection driver circuit.
11. Verifies a proper Cam signal circuit voltage of 7 to 9 volts and a good ground from the C(3)I module to terminal "B" of the sensor connector.

12. Determines if reason for incorrect voltage reading was due to a fault in CKT 633, an open in CKT 632 or a faulty C(3)I module.