Shift Interlock System

DIAGNOSIS AND TESTING - SHIFT INTERLOCK SYSTEM




Figure 1 - Ignition Key/Switch Positions





If the shifter cannot be shifted out of Park or can be shifted out of Park without depressing the brake pedal, follow diagnostics procedure below.

Diagnostic and Repair procedure:

1. Engage the parking brake.
2. Connect the Wi-Tech scan tool to the vehicle.
3. Check for any DTCs that relate to the "Brake Switch or Brake Transmission Shift Interlock" in the WCM (wireless control module), PCM (powertrain control module) and TIPM (totally integrated power module).
4. For all Diagnostic Trouble Codes, perform the appropriate diagnostic procedure(s) and verification procedures according to Tech Connect.
5. Continue to step 6 if shifter still shows condition, otherwise stop and perform the Final Verification Test at the end of this procedure.
6. Using Wi-Tech, under the WCM module in the "Data" screen check for change in state of the following signals. If no change in state then perform corresponding circuit repairs:
a. "Gated park switch". Push and release button on shifter knob.
b. "BTSI feedback". Push and release brake pedal.
c. "Brake switch". Push and release brake pedal.
7. If change in state occurs in steps 6a, 6b, 6c then using Wi-Tech under the WCM module in the "Actuation" screen, actuate BTSI. (If shifter can now be released then follow a), (Otherwise b)
a. Refer to "System Shift Interlock" and check for mechanical shifter issues.
b. Go To BRAKE TRANSMISSION SHIFT INTERLOCK (BTSI) CIRCUIT TEST

BRAKE TRANSMISSION SHIFT INTERLOCK (BTSI) CIRCUIT TEST




1. Turn the ignition off.
2. Disconnect the BTSI connector on the shifter. NOTE: The graphic shows a typical shifter connector. Refer to the Wiring Information for the appropriate shifter connector.

3. Connect a 12-volt test light between the Ground and the (K321) Brake Transmission Shift Interlock Solenoid Unlock circuits.
4. Turn the ignition on.
5. While observing the test light, push and release the brake pedal.

Does the test light illuminate brightly when the brake pedal is pushed?

Yes

- Replace the shifter.
- Perform the Final Verification Test listed below.

No

- Trace and repair the open Ground or the Open (K321) Brake Transmission Shift Interlock Solenoid Unlock circuits as necessary.
- Perform the Final Verification Test listed below.

Final Verification Testing: