Circuit/System Testing

Ignition OFF, disconnect the harness connectors at the ECM.
Ignition OFF and scan tool disconnected, open and close the driver door, and wait 1 minute. Test for less than 5 ohms between the ground circuit terminals listed below and ground:
- Terminal 1 X2 (3.6L LY7 LTT)
- Terminal 2 X2 (3.6L LY7 LTT)
- Terminal 4 X2 (3.6L LY7 LTT)
- Terminal 73 X2 (4.4L LC3 4.6L LH2)
- Terminal 73 X3 (4.4L LC3 4.6L LH2)
- If greater than the specified range, test the ground circuits for an open/high resistance.
Ignition ON, verify a test lamp illuminates between the B+ / IGN circuit terminals listed below and ground.
- IGN terminal 3 X2 (3.6L LY7 LTT)
- IGN terminal 5 X2 (3.6L LY7 LTT)
- IGN terminal 6 X2 (3.6L LY7 LTT)
- IGN terminal 54 X2 (3.6L LY7 LTT)
- B+ terminal 56 X2 (3.6L LY7 LTT)
- IGN terminal 13 X2 (4.4L LC3 4.6L LH2)
- IGN terminal 28 X2 (4.4L LC3 4.6L LH2)
- IGN terminal 19 X1 (4.4L LC3 4.6L LH2)
- B+ terminal 20 X1 (4.4L LC3 4.6L LH2)
- If the test lamp did not illuminate, test the B+ / IGN circuits for an open/high resistance.
If the circuits test normal, replace the ECM.