Contents Wiring diagrams Section: Automatic Trans All sections

Shift Interlock System: Overview Chevrolet Silverado 2500 HD

Automatic Trans 3 illustrations ~477 words

Scheme 399

Scheme 399: Shift Lock Control Schematics

Scheme 400

Scheme 400: Shift Lock Control Component Views
CalloutComponent Name
1Turn Signal Multifunction Switch
2Ignition Lock Cylinder
3Tow/Haul Switch
4Steering Angle Sensor
5A/T Shift Lock Control Solenoid
6Theft Deterrent Control Module
7Ignition Switch
8Inflatable Restraint Steering Wheel Module Coil

Scheme 401

Scheme 401: A/T Shift Lock Control Solenoid
Connector Part Information OEM: 12052832 Service: 12101825 Description: 2-Way F Metri-Pack 150 Series (GY) Terminal/Tray: 12047767/2 Core/Insulation Crimp: E/A Release Tool/Test Probe: 12094429/J-35616-2A (GY)

A/T Shift Lock Control Solenoid Connector Parts Information

PinWire ColorCircuit No.Function
A0.35 TN/WH816A/T Shift Lock Solenoid Supply Voltage
B0.5 BK1050Ground

A/T Shift Lock Control Solenoid Connector Terminal Identification

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. 2: Listen for an audible click when the automatic transmission shift lock control solenoid operates. Command both the ON and OFF states. Repeat the commands as necessary.
  2. 3: This step tests for a good ground at the ground circuit of the automatic transmission shift lock control solenoid.
  3. 4: This step verifies that the BCM is providing battery voltage to the automatic transmission shift lock control solenoid.
  4. 5: This step tests if battery voltage is constantly being applied to the automatic transmission shift lock control solenoid.
StepActionYesNo
Schematic Reference: Shift Lock Control Schematics Connector End View Reference: Shift Lock Control Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle
2Install a scan tool. Turn ON the ignition, with the engine OFF. With a scan tool, command the Shift Lock Solenoid output control ON and OFF. Does the automatic transmission shift lock control solenoid turn ON and OFF with each command?Go to Testing for Intermittent Conditions and Poor ConnectionsGo to Step 3
3Turn OFF the ignition. Disconnect the automatic transmission shift lock control solenoid. Connect a test lamp between the shift lock control solenoid ground circuit at the connector of the shift lock control solenoid and battery positive voltage. Does the test lamp illuminate?Go to Step 4Go to Step 10
4Turn OFF the ignition. Connect a test lamp between the shift lock solenoid control circuit and the shift lock solenoid ground circuit at the connector of the shift lock control solenoid. With a scan tool, command the Shift Lock Solenoid output control ON and OFF several times. Does the test lamp turn ON and OFF with each command?Go to Step 8Go to Step 5
5Does the test lamp remain illuminated?Go to Step 6Go to Step 7
6Test the control circuit of the automatic transmission shift lock control solenoid for a short to battery voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 13Go to Step 9
7Test the control circuit of the automatic transmission shift lock control solenoid for an open or short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 13Go to Step 9
8Inspect 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 13Go to Step 11
9Inspect for poor connections at the harness connector of the body control module (BCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?Go to Step 13Go to Step 12
10Repair the open in the automatic transmission shift lock control ground circuit. Refer to Circuit Testing and Wiring Repairs . Did you complete the repair?Go to Step 13
11Replace the automatic transmission shift lock control solenoid. Refer Automatic Transmission Shift Lock Actuator Replacement . Did you complete the replacement?Go to Step 13
12Replace the BCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement?Go to Step 13
13Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTC, as specified in the supporting text. Does the DTC reset?Go to Step 2System OK

DTC B2705

Symptoms - Automatic Transmission Shift Lock Control

IMPORTANTThe following steps must be completed before using the symptom tables.
  1. Perform the «Diagnostic System Check - Vehicle»(ref-278018-S19353494792008012100000) before using the Symptom Tables in order to verify that all of the following are true: There are no DTCs set. The control modules can communicate via the serial data link.
  2. Review the system operation in order to familiarize yourself with the system functions. Refer to «Automatic Transmission Shift Lock Control Description and Operation»(ref-278062-S17450862112008012100000) .

Automatic Transmission Shift Lock Control Description and Operation

The automatic transmission shift lock control system is a safety device that prevents an inadvertent shift out of PARK when the engine is running. The driver must press the brake pedal before moving the shift lever out of the PARK position. The system consists of the automatic transmission shift lock solenoid (serviced as the automatic transmission shift lock actuator), as well as the body control module (BCM) and engine control module (ECM). The shift lock solenoid is located within the steering column assembly.

The BCM controls the voltage supply circuit of the shift lock control solenoid. The following conditions must be met before the BCM will supply voltage to the shift lock control solenoid

  1. The ignition is in the ON position.
  2. The ECM sends an input via GMLAN serial data to the BCM indicating the transmission is in the PARK position.
  3. The BCM determines the brake pedal is not applied according to the stop lamp switch.

Since the shift lock control solenoid is permanently grounded, the BCM supplies voltage to the automatic transmission shift lock control solenoid, mechanically locking the shift lever in the PARK position as the solenoid energizes. When the brake pedal is applied, the BCM turns the control voltage output of the shift lock control solenoid OFF, de-energizing the shift lock control solenoid. The de-energized solenoid releases the mechanical lock allowing the driver to move the shift lever out of the PARK position. When the transmission is out of the PARK position, the shift lock control solenoid remains de-energized.

During remote start operation the BCM will energize the shift lock control circuit, locking the shift lever in the PARK position.