Voltage Signal: Testing and Inspection

Power Supply Schematic:

Power to the ECU is supplied from the battery direct to terminal 9. It is also applied to terminals 7 and 8 when the ignition switch is in the on position.

HARNESS TEST

1. Disconnect the ECU harness connector. Using a voltmeter, measure the battery supply voltage at the ECU harness connector terminal 9.

Voltage: System Voltage.

2. Turn on the ignition. Using a voltmeter, measure the supply voltage at the ECU harness connector terminals 7 and 8.

Voltage: System Voltage.

If any of the previous tests produce unsatisfactory results, the harness will need to be repaired or replaced. Once repairs have been completed, road test the vehicle to confirm that the repair has corrected the problem.

If the same problem reoccurs, it is possible that there is an intermittent failure of the component or the ECU. Check for looseness at all harness junctions and test for an intermittent failure.