NAG1 Shifter - ESM

P0931-BTSI CONTROL CIRCUIT HIGH - ESM





For a complete wiring diagram Refer to Diagrams/Electrical Electrical Diagrams


- When Monitored:

Continuously with the ignition key on.

- Set Condition:

The DTC will set if the high side driver detects an open load for 10 seconds.







Always perform the NAG1 Pre-Diagnostic Troubleshooting procedure before proceeding. NAG1 - Pre-Diagnostic Troubleshooting Procedure


Theory of Operation


The brake switch signal must be active before the shift lever can be moved out of the park position. The Shifter Lever Assembly (SLA) Electronic Shift Module (ESM) receives two brake switch signals. The first signal is a CAN C Bus message sent to the shifter lever assembly. The second signal is a hard wired brake switch signal to the shifter lever assembly. The CAN C Bus message is the primary brake switch signal and the hard wired signal serves as the backup brake switch signal. These two brake switch signals are compared against each other to verify proper brake switch operation.



Diagnostic Test


1. ENGINE DTCs PRESENT

With the scan tool, read Engine DTCs.

Are there any Engine brake DTCs present?

Yes


- Perform NAG1 TRANSMISSION VERIFICATION TEST. NAG1 Transmission Verification Test

No

- Go To 2



2. ABS MODULE DTCs PRESENT

With the scan tool, read ABS Module DTCs.

Are there any ABS DTCs present?

Yes

- Refer to Brakes and Traction Control/Testing and Inspection and perform the appropriate diagnostic procedure.
- Perform NAG1 TRANSMISSION VERIFICATION TEST. NAG1 Transmission Verification Test

No

- Go To 3



3. (B29) BRAKE SWITCH SIGNAL OPEN





Turn the ignition off to the lock position.

Disconnect the Shifter Lever Assembly harness connector.

Disconnect the Stop Lamp Switch harness connector.


NOTE: Check connectors - Clean/repair as necessary.

Measure the resistance of the (B29) Brake Switch Signal circuit between the Shifter Lever Assembly harness connector and the Stop Lamp Switch.

Is the resistance above 5.0 ohms?

Yes

- Repair the (B29) Brake Switch Signal for an open.
- Perform NAG1 TRANSMISSION VERIFICATION TEST. NAG1 Transmission Verification Test

No

- Go To 4



4. (B29) BRAKE SWITCH SIGNAL SHORT TO VOLTAGE





Turn the ignition off to the lock position.

Disconnect the Shifter Lever Assembly harness connector.


NOTE: Check connectors - Clean/repair as necessary.

Turn the ignition on.

Measure the voltage of the (B29) Brake Switch Signal circuit.

Is the voltage above 0.5 volts?

Yes

- Repair the (B29) Brake Switch Signal for a short to voltage.
- Perform NAG1 TRANSMISSION VERIFICATION TEST. NAG1 Transmission Verification Test

No

- Replace the Shifter Lever Assembly.
- Perform NAG1 TRANSMISSION VERIFICATION TEST. NAG1 Transmission Verification Test