Shift Lever Can Be Moved without Brake Pedal Depressed. GMC Truck Sonoma Pickup

For 1990-2009 cars only

Makes 🢒 GMC_Truck 🢒 2001 🢒 Sonoma Pickup - 2WD 🢒 Transmission/Transaxle 🢒 Shift Lock Control 🢒 Shift Lever Can Be Moved without Brake Pedal Depressed

Shift Lever Can Be Moved without Brake Pedal Depressed Column Shift

Step

Action

Yes

Schematic Reference: Shift Lock Control Schematics

DEFINITION: Transmission shift lever does not lock in the PARK position with the ignition ON and the brake pedal not pressed.

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

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 in Wiring Systems

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

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

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

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

Test the automatic transmission shift lock control solenoid ground circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 20

Go to Step 12

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

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

•	Inspect for proper park/neutral position switch adjustment. Refer to Park/Neutral Position Switch Adjustment in Automatic Transmission.

•	Inspect for poor connections at the park/neutral position switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 20

Go to Step 17

Inspect for poor connections at the automatic transmission shift lock control switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 20

Go to Step 18

Inspect for poor connections at the automatic transmission shift lock control solenoid. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 20

Go to Step 19

Repair the open or short in the ignition 1 voltage circuit of the park/neutral position switch. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 20

Repair the open or short in the A/T shift lock switch supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 20

Repair the open in the A/T shift lock control solenoid supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 20

Repair the open or short in the park/neutral position switch park signal circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 20

Replace the park/neutral position switch. Refer to Park/Neutral Position Switch Replacement in Automatic Transmission.

Did you complete the replacement?

Go to Step 20

Replace the automatic transmission shift lock control switch. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes.

Did you complete the replacement?

Go to Step 20

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

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 Floor Shift

Step	Action	Yes	No
Schematic Reference: Shift Lock Control Schematics 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 in Wiring Systems
3	Place shift lever in the PARK position. Turn OFF the ignition. 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 Park Lock Solenoid Inoperative	Go to Step 4
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 10
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 8
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 11
7	Test the automatic transmission shift lock control solenoid ground circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 14	Go to Step 9
8	Inspect for poor connections at the automatic transmission shift lock control switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 14	Go to Step 12
9	Inspect for poor connections at the automatic transmission shift lock control solenoid. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 14	Go to Step 13
10	Repair the open or short in the A/T shift lock switch supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair?	Go to Step 14	--
11	Repair the open in the A/T shift lock control solenoid supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair?	Go to Step 14	--
12	Replace the automatic transmission shift lock control switch. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes. Did you complete the replacement?	Go to Step 14	--
13	Replace the automatic transmission shift lock control solenoid. Refer to Automatic Transmission Shift Lock Actuator Replacement . Did you complete the replacement?	Go to Step 14	--
14	Operate the system in order to verify the repair. Did you find and correct the condition?	System OK	Go to Step 2