P0928

P0928-BTSI CONTROL CIRCUIT





For a complete wiring diagram, refer to the Wiring Information.

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 (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 Wireless Ignition Node (WIN). 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 Diagnostic trouble Code (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

1. POWERTRAIN BRAKE SWITCH DTCs
1. With the scan tool, read Engine DTCs.

Are there any Powertrain DTCs relating to the Brake Switch present?

Yes

- Perform the appropriate diagnostic procedure relating to the Powertrain Brake Switch. Testing and Inspection
- Perform the NAG1 TRANSMISSION VERIFICATION TEST. NAG1 Transmission Verification Test

No

- Go To 2

2. CHECK THE (K321) BTSI CONTROL CIRCUIT




1. Turn the ignition off to the lock position.
2. Disconnect the Shifter Lever Assembly harness connector.
3. Ignition on, engine not running.
4. With the scan tool under WIN, actuate the BTSI.

NOTE: Check connectors - Clean/repair as necessary.

5. Using a 12 volt test light connected to ground, check the (K321) BTSI Control circuit.

Does the test light illuminate brightly while cycling the (K321) BTSI Control circuit on and off?

Yes

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

No

- Go To 3

3. (K321) BTSI CONTROL CIRCUIT SHORT TO GROUND




1. Turn the ignition off to the lock position.
2. Disconnect the WIN harness connector.

NOTE: Check connectors - Clean/repair as necessary.

3. 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 the NAG1 TRANSMISSION VERIFICATION TEST. NAG1 Transmission Verification Test

No

- Go To 4

4. (K321) BTSI CONTROL CIRCUIT OPEN




1. Turn the ignition off to the lock position.

NOTE: Check connectors - Clean/repair as necessary.

2. Measure the resistance of the (K321) BTSI Control circuit between the Shifter Lever Assembly harness connector and the WIN harness connector.

Is the resistance above 5.0 ohms?

Yes

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

No

- Go To 5

5. (K321) BTSI CONTROL CIRCUIT SHORT TO VOLTAGE




1. Turn the ignition off to the lock position.
2. Disconnect the Shifter Lever Assembly harness connector.
3. Disconnect the WIN harness connector.
4. Turn the ignition on.

NOTE: Check connectors - Clean/repair as necessary.

5. Measure the voltage between ground and the (K321) BTSI Control circuit.

Is the voltage above 10 volts?

Yes

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

No

- Go To 6

6. WIRELESS IGNITION NODE
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:

- Replace the Wireless Ignition Node.
- Perform the NAG1 TRANSMISSION VERIFICATION TEST. NAG1 Transmission Verification Test