Part 2 of 3

Chart A-3:

Ignition Circuit:

TEST DESCRIPTION: Number(s) below refer to circled number(s) on the diagnostic chart.

1. Checks for 12 volt supply to injectors. Because the injectors are wired in parallel there should be a light "ON" on both terminals.

2. Check continuity of CKT 467 and 468.

3. All checks made to this point would indicate that the ECM is at fault. However, there is a possibility of CKT 467 or 468 being shorted to a voltage source either in the engine harness or in the injector harness.

To test for this condition:

^ Disconnect the injector 4-way connector.
^ Ignition "ON."
^ Probe CKTs 467 and 468 on the ECM side of harness with a test light connected to ground. There should be no light. If light is "ON," repair short to voltage.
^ If OK, check the resistance of the injector harness between terminals "A" & "C," "A" & "D," "B" & "D," and "B" & "C."
^ Should be more than 4 ohms.
^ If less than 4 ohms, check harness for wires shorted together and check each injector resistance. (Resistance should be 8 ohms or more.)
^ If all OK, replace ECM.