Ignition Start Input Mismatch - IPM

IGNITION START INPUT MISMATCH - IPM





For a complete wiring diagram Consult Diagrams/Electrical

- When Monitored:
When the IPM is powered up.

- Set Condition:
The IPM internal sense detects the hardwired Ignition Switch I/O = "OFF" and the Ignition State in Monitors = "Start" (BCM Ignition Switch MUX-based PCI bus data) for 5 seconds.





Diagnostic Test

1. PRETEST

NOTE: Diagnose and repair any BCM Ignition MUX or IPM Ignition Run-Start Mismatch DTC's before proceeding with this test.

Turn the ignition off.
Remove and inspect Fuse #30 in the IPM.
If fuse is open, replace with proper rated fuse.
Remove the Starter Relay from the IPM.
Turn the ignition to the Start position for at least 5 seconds.
Turn the ignition off.
Remove and inspect Fuse #30 in the IPM.
Is IPM Fuse #30 open?

Yes

- Go To2

No

- Go To5

2. (T751) IGNITION SWITCH OUTPUT (START) CIRCUIT SHORT TO GROUND - IPM




Turn the ignition off.
Disconnect the IPM harness C4 connector.
Disconnect the Ignition Switch harness connector.
Measure the resistance between ground and the (T751) Ignition Switch Output (Start) circuit.
Is the resistance below 5 ohms?

Yes

- Repair the (T751) Ignition Switch Output (Start) circuit for a short to ground between the IPM and the Ignition Switch.
- Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test.

No

- Go To3

3. (T751) IGNITION SWITCH OUTPUT (START) CIRCUIT SHORT TO GROUND - PCM




Turn the ignition off.
Disconnect the IPM C7 harness connector.
Disconnect the PCM harness connector.
Measure the resistance between ground and the (T751) Ignition Switch Output (Start) circuit between the IPM and the PCM.
Is the resistance below 5.0 ohms?

Yes

- Repair the (T751) Ignition Switch Output (Start) circuit for a short to ground between the IPM and the PCM.
- Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test.

No

- Go To4

4. IPM INTERNAL SHORT




Turn the ignition off.
Reconnect the Ignition Switch harness connector.
Reconnect the IPM C4 harness connector.
Install proper rated fuse to IPM Fuse #30.
Turn the ignition to the Start position for at least 5 seconds.
With the scan tool, read DTCs.
Did this DTC reset?

Yes

- Replace the IPM.
- Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test.

No

- The condition is not present at this time. Monitor scan tool parameters while wiggling the related wire harness. Search for any Technical Service Bulletins (TSB) that may apply. Visually inspect the related wiring harness and connector terminals.
- Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test.

5. IPM INTERNAL OPEN




Turn the ignition off.
Disconnect the IPM C4 harness connector.
Measure the voltage of the (T751) Ignition Switch Output (Start) circuit while holding the Ignition Switch in the Start position.
Does the test light illuminate brightly?

Yes

- Replace the IPM.
- Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test.

No

- Go To6

6. (T751) IGNITION SWITCH OUTPUT (START) CIRCUIT OPEN




Turn the ignition off.
Disconnect the IPM C4 harness connector.
Disconnect the Ignition Switch harness connector.
Measure the resistance of the (T751) Ignition Switch Output (Start) circuit between the IPM C4 connector and the Ignition Switch connector.
Is the resistance above 5.0 ohms?

Yes

- Repair the (T751) Ignition Switch Output (Start) circuit for an open.
- Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test.

No

- Go To7

7. IGNITION SWITCH
Turn the ignition off.
Disconnect the IPM C4 harness connector.
While back probing, measure the voltage of the (T751) Ignition Switch Output (Start) circuit while holding the Ignition switch in the Start position.
Is the voltage below 10.5 volts?

Yes

- Replace the Ignition Switch.
- Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test.

No

- The condition is not present at this time. Monitor scan tool parameters while wiggling the related wire harness. Search for any Technical Service Bulletins (TSB) that may apply. Visually inspect the related wiring harness and connector terminals.
- Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test.