NAG1 Shifter - ESM (Column Shift)

P0930-BTSI CONTROL CIRCUIT LOW - ESM (COLUMN SHIFT)





For a complete wiring diagramconsult Diagrams/Electrical

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 from the WCM. 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.


- When Monitored:
Continuously with the ignition on.

- Set Condition:
The DTC will set if the high side driver detects a short to ground for 10 seconds.







Always perform the NAG1 Pre-Diagnostic Troubleshooting procedure before proceeding. Testing and Inspection


Diagnostic Test


1. ENGINE DTCS PRESENT
With the scan tool, read Engine DTCs.
Are there any Engine brake DTCs present?

Yes


- Diagnose and repair the DTC(s).
- Perform NAG1 TRANSMISSION VERIFICATION TEST. Transmission Verification Test


No


- Go To 2




2. WCM DTCS PRESENT
With the scan tool, read WCM DTCs.
Are there any WCM DTCs present?

Yes


- Diagnose and repair the DTC(s).
- Perform NAG1 TRANSMISSION VERIFICATION TEST. Transmission Verification Test


No


- Go To 3




3. (K321) BTSI CONTROL CIRCUIT SHORT TO GROUND




Turn the ignition off to the lock position.
Disconnect the ESM C1 harness connector.
Ignition on, engine not running.
With the scan tool under WCM, actuate the BTSI.

NOTE: Check connectors - Clean/repair as necessary.

Using a 12 volt test light connected to ground, check the (K321) BTSI Control circuit.
Does the test light illuminate brightly while cycling on and off on all (K321) BTSI Control circuit?

Yes


- Replace the Electronic Shift Module (ESM).
- Perform NAG1 TRANSMISSION VERIFICATION TEST. Transmission Verification Test


No


- Go To 4




4. (K321) BTSI CONTROL CIRCUIT SHORT TO GROUND




Turn the ignition off to the lock position.
Disconnect the WCM harness connector.

NOTE: Check connectors - Clean/repair as necessary.

Measure the resistance between ground and the (K321) BTSI Control circuit.
Is the resistance below 5.0 ohms?

Yes


- Repair the (K321) BTSI Control circuit for a short to ground.
- Perform NAG1 TRANSMISSION VERIFICATION TEST. Transmission Verification Test


No


- Go To 5




5. (K321) BTSI CONTROL CIRCUIT OPEN




Turn the ignition off to the lock position.

NOTE: Check connectors - Clean/repair as necessary.

Measure the resistance of the (K321) BTSI Control circuit between the Electronic Shift Module (ESM) harness connector and the WCM harness connector.
Is the resistance above 5.0 ohms?

Yes


- Repair the (K321) BTSI Control circuit for an open.
- Perform NAG1 TRANSMISSION VERIFICATION TEST. Transmission Verification Test


No


- Go To 6




6. ELECTRONIC SHIFT MODULE (ESM)
Using the schematics as a guide, inspect the wiring and connectors. Repair as necessary. Pay particular attention to all power and ground circuits.
If there are no possible causes remaining, view repair.

Repair


- Replace the Electronic Shift Module (ESM).
- Perform NAG1 TRANSMISSION VERIFICATION TEST. Transmission Verification Test