Circuit/System Testing

PNP Switch Circuit Malfunction - 4T45-E (ME7/MN5)

1. Inspect the shift control cable for proper adjustment. Refer to Shift Control Cable Adjustment .
2. Ignition OFF, disconnect the harness connector at the PNP switch.
3. Ignition OFF and scan tool disconnected, open and close the driver door, and wait 30 seconds. Test for less than 5 Ω between the following switch ground circuit terminals and ground:
   • Terminal 1 X1 (ME7)
   • Terminal 11 X1 (MN5)
   • If greater than the specified range, test the ground circuit for an open/high resistance.
4. Ignition ON, switch disconnected, verify that the scan tool ECM PNP Switch parameter is In Gear.
   • If not the specified value, test the signal circuit terminal 7 X1 (MN5) or terminal 12 X1 (ME7) for a short to ground. If the circuit tests normal, replace the ECM.
5. Install a 3 A fused jumper wire between the ground circuit and the signal circuit. Verify that the scan tool PNP Switch parameter is Park/Neutral.
   • If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
6. If all circuits test normal, test or replace the PNP switch.

PNP Switch Circuit Malfunction - 6T70 (MH2/MH4)

1. Inspect the range selector lever cable for proper adjustment. Refer to Range Selector Lever Cable Adjustment .
2. Ignition OFF, disconnect the inline 20-way harness connector at the transmission.
3. Ignition ON, test for greater than 5 V on the park/neutral signal circuit terminal 20.
   • If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
4. Ignition OFF, remove the control valve body cover. Refer to Control Valve Body Cover Replacement .
5. Connect the transmission inline 20-way connector, with the cover removed.
6. Disconnect the internal mode switch connector at the control solenoid valve assembly.
7. Ignition ON, verify that the scan tool ECM PNP Switch parameter is In Gear.
   • If not the specified value, test the signal circuit for a short to ground. If the circuit tests normal, replace the ECM.
8. Connect a 3 A fused jumper wire between the park/neutral signal terminal F at the control solenoid valve assembly and ground. The scan tool ECM PNP Switch parameter should be Park/Neutral.
   • If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
9. If all circuits test normal, test or replace the internal mode switch.

STRTR Relay Circuit Malfunction

1. Ignition OFF, disconnect the STRTR relay.
2. Ignition OFF and scan tool disconnected, open and close the driver door, and wait 30 seconds. Test for less than 5 Ω between the ground circuit terminal 85 and ground.
   • If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 30 and ground.
   • If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the STARTER fuse is open, test the starter control circuit terminal 87 for a short to ground.
4. Ignition OFF and transmission in park, connect a 30 A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. The engine should begin cranking.
   • If the engine does not crank, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the starter.
5. Connect a test lamp between the ground circuit terminal 85 and the control circuit terminal 86.
6. Ignition ON and transmission in park, cycle the ignition switch between OFF and START. The test lamp should turn ON and OFF when changing between the commanded states.
   • If the test lamp is always ON, test the relay control circuit terminal 86 for a short to voltage. If the circuit tests normal, replace the ECM.
   • If the test lamp is always OFF, test the relay control circuit terminal 86 for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
7. If all circuits test normal, test or replace the STRTR relay.