Intermittent
Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections .
Shift Lever Does Not Move with Brake Pedal Depressed
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Shift Lock Control Schematics Connector End View Reference: Master Electrical Component List DEFINITION: Transmission shift lever will not move out of the PARK position with the ignition ON and the brake pedal pressed. | |||
| 1 | Did you perform the Symptoms - Automatic Transmission Shift Lock Control tests and all the necessary inspection? | Go to Step 2 | Go to Symptoms - Automatic Transmission Shift Lock Control |
| 2 | Turn ON the ignition, with the engine OFF. Press and hold the brake pedal. Attempt to move the shift lever out of the PARK position. Does the shift lever move out of the PARK position? | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 3 |
| 3 | Turn OFF the ignition. Disconnect the automatic transmission shift lock control switch. Turn ON the ignition, with the engine OFF. Press and hold the brake pedal. Attempt to move the transmission shift lever out of the PARK position. Does the transmission shift lever move out of the PARK position? | Go to Step 6 | Go to Step 4 |
| 4 | Turn OFF the ignition. Disconnect the automatic transmission shift lock control solenoid. Turn ON the ignition, with the engine OFF. Press and hold the brake pedal. Attempt to move the transmission shift lever out of the PARK position. Does the transmission shift lever move out of the PARK position? | Go to Step 7 | Go to Step 5 |
| 5 | Inspect for poor connections at the harness connector of the automatic transmission shift lock control solenoid. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 10 | Go to Step 9 |
| 6 | Inspect for poor connections at the harness connector of the automatic transmission shift lock control switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 10 | Go to Step 8 |
| 7 | Repair the short to battery positive voltage in the A/T shift lock control solenoid supply voltage circuit. Refer to Circuit Testing and Wiring Repairs . Did you complete the repair? | Go to Step 10 | |
| 8 | Replace the automatic transmission shift lock control switch. Refer to Stop Lamp Switch Replacement . Did you complete the replacement? | Go to Step 10 | |
| 9 | Replace the automatic transmission shift lock control solenoid. Refer to Automatic Transmission Shift Lock Actuator Replacement . Did you complete the replacement? | Go to Step 10 | |
| 10 | Operate the system in order to verify the repair. Did you find and correct the condition? | System OK | Go to Step 2 |
Shift Lever Does Not Move with Brake Pedal Depressed
Shift Lever Can Be Moved without Brake Pedal Depressed (w/o Allison Transmission)
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Shift Lock Control Schematics Connector End View Reference: Master Electrical Component List DEFINITION: Transmission shift lever does not lock in the PARK position with the ignition ON and the brake pedal not pressed. | |||
| 1 | Did you perform the Symptoms - Automatic Transmission Shift Lock Control tests and all the necessary inspections? | Go to Step 2 | Go to Symptoms - Automatic Transmission Shift Lock Control |
| 2 | Apply the parking brake and block the wheels. Turn ON, the ignition, with the engine OFF. Attempt to move the shift lever out of the PARK position. Does the shift lever move out of the PARK position? | Go to Step 3 | Go to Testing for Intermittent Conditions and Poor Connections |
| 3 | Turn OFF the ignition. Ensure transmission shift lever is in the PARK position. Connect a test lamp between the A/T shift lock switch supply voltage circuit at the BTSI fuse and a good ground. Turn ON the ignition, with the engine OFF. Does the test lamp illuminate? | Go to Step 4 | Go to Step 8 |
| 4 | Connect a test lamp between the A/T shift lock switch supply voltage circuit at the automatic transmission shift lock control switch and a good ground. Does the test lamp illuminate? | Go to Step 5 | Go to Step 14 |
| 5 | Connect a test lamp between the A/T shift lock solenoid control circuit at the automatic transmission shift lock control switch and a good ground. Press and release the brake pedal several times. Does the test lamp turn ON and OFF with the brake pedal? | Go to Step 6 | Go to Step 11 |
| 6 | Connect a test lamp between the automatic transmission shift lock control solenoid supply voltage circuit at the automatic transmission shift lock control solenoid and a good ground. Does the test lamp illuminate? | Go to Step 7 | Go to Step 15 |
| 7 | Test the automatic transmission shift lock control solenoid ground circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 20 | Go to Step 12 |
| 8 | Turn OFF the ignition. Disconnect the park/neutral position switch connector. Connect a test lamp between the ignition 1 voltage circuit of the park/neutral position switch and a good ground. Turn ON the ignition, with the engine OFF. Does the test lamp illuminate? | Go to Step 9 | Go to Step 13 |
| 9 | Turn OFF the ignition. Connect a 10 amp fused jumper between the ignition 1 voltage circuit of the park/neutral position switch and the park/neutral position switch park signal circuit at the park/neutral position switch connector. Connect a test lamp between the A/T shift lock switch supply circuit at the BTSI fuse and a good ground. Turn ON the ignition, with the engine OFF. Does the test lamp illuminate? | Go to Step 10 | Go to Step 16 |
| 10 | Inspect for proper park/neutral position switch adjustment. Refer to Park/Neutral Position Switch Adjustment for the 4L60-E transmission or Park/Neutral Position Switch Adjustment for the 4L80-E transmission. Inspect for poor connections at the harness connector of the park/neutral position switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 20 | Go to Step 17 |
| 11 | Inspect for poor connections at the harness connector of the automatic transmission shift lock control switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 20 | Go to Step 18 |
| 12 | Inspect for poor connections at the harness connector automatic transmission shift lock control solenoid. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 20 | Go to Step 19 |
| 13 | Repair the open or short in the ignition 1 voltage circuit of the park/neutral position switch. Refer to Circuit Testing and Wiring Repairs . Did you complete the repair? | Go to Step 20 | |
| 14 | Repair the open or short in the A/T shift lock switch supply voltage circuit. Refer to Circuit Testing and Wiring Repairs . Did you complete the repair? | Go to Step 20 | |
| 15 | Repair the open in the A/T shift lock control solenoid supply voltage circuit. Refer to Circuit Testing and Wiring Repairs . Did you complete the repair? | Go to Step 20 | |
| 16 | Repair the open or short in the park/neutral position switch park signal circuit. Refer to Circuit Testing and Wiring Repairs . Did you complete the repair? | Go to Step 20 | |
| 17 | Replace the park/neutral position switch. Refer to Park/Neutral Position Switch Replacement for the 4L60-E transmission or Park/Neutral Position Switch Replacement for the 4L80-E transmission. Did you complete the replacement? | Go to Step 20 | |
| 18 | Replace the automatic transmission shift lock control switch. Refer to Stop Lamp Switch Replacement . Did you complete the replacement? | Go to Step 20 | |
| 19 | Replace the automatic transmission shift lock control solenoid. Refer to Automatic Transmission Shift Lock Actuator Replacement . Did you complete the replacement? | Go to Step 20 | |
| 20 | Operate the system in order to verify the repair. Did you find and correct the condition? | System OK | Go to Step 2 |
Shift Lever Can Be Moved without Brake Pedal Depressed (w/o Allison Transmission)
Reference Information
Schematic Reference
Shift Lock Control Schematics
Connector End View Reference
Shift Lock Control Connector End Views
Electrical Information Reference
- «Circuit Testing»(ref-277884-S17422072462008012100000)
- «Connector Repairs»(ref-277884-S12371167392008012100000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-277884-S20700666652008012100000)
- «Wiring Repairs»(ref-277884-S08861102212008012100000)
Circuit/System Verification
With a scan tool, monitor the Trans. Range Sw. data to verify vehicle is in the Park position.
- If data does not display Park, replace the internal mode switch (IMS). Refer to «Transmission Internal Mode Switch Replacement»(ref-277908-S19726934332008012100000) .
Repair Procedures
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
- «Stop Lamp Switch Replacement»(ref-277846-S37456875212008012100000)
- «Automatic Transmission Shift Lock Actuator Replacement»(ref-277947-S05122336502008012100000)
- «Transmission Internal Mode Switch Replacement»(ref-277908-S19726934332008012100000)
- «Body Control Module Replacement»(ref-277861-S16446328882008012100000)
Automatic Transmission Shift Lock Control System with Allison Transmission
The automatic transmission shift lock control is a safety device that prevents an inadvertent shift out of PARK when the ignition is ON. The driver must press the brake pedal before moving the shift lever out of the PARK position. The system consists of the following components
- The automatic transmission shift lock control solenoid.
- The automatic transmission shift lock control switch.
- The body control module (BCM).
- The engine control module (ECM), if equipped with a 6.6L engine.
- The powertrain control module (PCM), if equipped with a 8.1L engine.
With the ignition in the ON position and the shift lever is in PARK, battery positive voltage is supplied from the BCM to the automatic transmission shift lock control solenoid through the normally-closed automatic transmission shift lock control switch. When the transmission control module (TCM) indicates the shift lever is in the PARK position, the ECM/PCM sends a class 2 serial data message to the BCM indicating the transmission is in the PARK position. This allows current to flow through the switch to the automatic transmission shift lock control solenoid. Since the automatic transmission shift lock control solenoid is permanently grounded, the shift lock control solenoid energizes, locking the shift linkage in the PARK position. When the driver presses the brake pedal the contacts in the automatic transmission shift lock control switch open, causing the automatic transmission shift lock control solenoid to de-energize, unlocking the shift lever from the PARK position.
Automatic Transmission Shift Lock Control System
The automatic transmission shift lock control is a safety device that prevents an inadvertent shift out of PARK when the ignition is ON. The driver must press the brake pedal before moving the shift lever out of the PARK position. The system consists of the following components
- The automatic transmission shift lock control solenoid.
- The automatic transmission shift lock control switch.
- The park/neutral position switch.
With the ignition in the ON position, battery positive voltage is supplied to the park/neutral position switch. When the transmission is in the PARK position the contacts in the park/neutral position switch are closed. This allows current to flow through the switch to the automatic transmission shift lock control switch. The circuit continues through the normally-closed switch to the automatic transmission shift lock control solenoid. The automatic transmission shift lock control solenoid is permanently grounded. This energizes the automatic transmission shift lock control solenoid, locking the shift linkage in the PARK position. When the driver presses the brake pedal the contacts in the automatic transmission shift lock control switch open, causing the automatic transmission shift lock control solenoid to release. This allows the shift lever to move from the PARK position.