Overdrive Switch: Testing and Inspection

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.

1. CHECK FOR DIAGNOSTIC TROUBLE CODES (DTC)
1. Engage the parking brake.
2. Connect the Wi-Tech scan tool to the vehicle.
3. Check the PCM (Powertrain Control Module) and the ABS (Antilock Brake System) for any Brake Switch related Diagnostic Trouble Codes (DTCs).

Are there any Brake Switch related DTCs?

Yes

- Refer to the appropriate engine or brake system and perform the appropriate diagnostic procedure(s).

No

- Go To 2

2. BRAKE SWITCH
1. With the scan tool select "PCM Module" and "Data Display". Read the Brake Switch state.
2. Check for change of state by pushing and releasing the brake pedal.

Does the brake switch change states when the pedal is pushed and released?

Yes

- Go To 3

No

- Trace and repair the Brake Switch circuit(s) as necessary.
- Perform the BODY VERIFICATION TEST. Body Verification Test

3. BRAKE TRANSMISSION SHIFT INTERLOCK (BTSI) TEST
1. Turn the ignition off.
2. Remove the necessary parts of the center console to visually see the BTSI Lever on the shifter.
3. Turn the ignition on.
4. While observing the BTSI Lever on the shifter, push and release the brake pedal several times.

Did the BTSI Lever move when the brake pedal was pushed and released?

Yes

- Refer to the appropriate transmission and select "Cable-Shift Interlock" "Diagnosis and Testing" and check for mechanical shifter issues.

No

- Go To 4

4. BRAKE TRANSMISSION SHIFT INTERLOCK (BTSI) CIRCUIT TEST




1. Turn the ignition off.
2. Disconnect the BTSI connector on the shifter. NOTE: The graphic shows the JS connector. Refer to the Wiring Information for other vehicles.

3. Connect a 12 volt test light between the (Z) 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 (Z) Ground or the Open (K321) Brake Transmission Shift Interlock Solenoid Unlock circuits as necessary.
- Perform the Final Verification Test listed below.

Final Verification Testing: