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 (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 Transmission Switch Interlock (BTSI) Control 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 WIN detects a short to ground, open or disconnected (K321) BTSI Control circuit, for more than 10 seconds.





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

1. ENGINE DTCS PRESENT
1. With the scan tool, read the PCM DTCs.

Are there any Powertrain Control Module (PCM) brake related DTCs present?

Yes

- Testing and Inspection and perform the appropriate diagnostic procedure.

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.

NOTE: Check connectors - Clean/repair as necessary.

3. Turn the ignition on, engine not running.
4. Using a 12-volt test light connected to ground, check the (K321) BTSI Control circuit in the Shifter Lever Assembly connector.
5. With the scan tool under WIN, actuate the BTSI.

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

Yes

- Replace the Shifter Lever Assembly. Transmission Shifter - Removal.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Go To 3

3. (K321) BTSI CONTROL CIRCUIT SHORTED 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 in the Shifter Lever harness connector.
4. Measure the resistance between ground and the (K321) BTSI Control circuit in the WIN harness connector.

Is the resistance below 10K Ohms in either connector?

Yes

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

No

- Go To 4

4. (K321) BTSI CONTROL CIRCUIT OPEN




1. 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 2.0 Ohms?

Yes

- Repair the (K321) BTSI Control circuit for an open.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Go To 5

5. (K321) BTSI CONTROL CIRCUIT SHORTED TO VOLTAGE




1. Turn the ignition on.
2. Measure the voltage between ground and the (K321) BTSI Control circuit.

Is there any voltage present?

Yes

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

No

- Replace and program the Wireless Ignition Node (WIN). Wireless Ignition Node Receiver - Removal.
- Perform the WIN VERIFICATION TEST. Wireless Ignition Node (WIN) Verification Test.