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Shift Interlock System Cadillac DTS I

Automatic Trans 1 illustration ~2956 words

Scheme 83

Scheme 83: Shift Lock Control Schematics
Scheme 83: Shift Lock Control Schematics

DIAGNOSTIC CODE INDEX

DTCDescription
DTC B2705B2705 02: Gearshift Unlock Circuit Short to Ground

DIAGNOSTIC CODE INDEX

Diagnostic Starting Point - Automatic Transmission Shift Lock Control

Begin the system diagnosis with the Diagnostic System Check - Vehicle . The Diagnostic System Check will provide the following information

  1. The identification of the control modules which command the system
  2. The ability of the control modules to communicate through the serial data circuit
  3. The identification of any stored diagnostic trouble codes (DTCs) and their status

The use of the Diagnostic System Check will identify the correct procedure for diagnosing the system and where the procedure is located.

Diagnostic Instructions

  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Diagnostic Fault Information

CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Shift Lock Control Solenoid Control CircuitB2705 021
Shift Lock Control Solenoid Ground Circuit1
1. Unable to move gearshift lever with brake pedal depressed

Circuit/System Description

The body control module (BCM) controls the automatic transmission shift lock control solenoid by providing a battery positive voltage to the solenoid. The BCM utilizes a smart driver to control the voltage supply circuit to the automatic transmission shift lock control solenoid. The smart driver monitors the voltage and current flow of the control circuit.

Conditions for Running the DTC

  1. The ignition switch is in the ON position.
  2. The brake pedal is pressed.
  3. The transmission is in the PARK position.

Conditions for Setting the DTC

Sets if there is a short to ground in the automatic transmission shift lock control solenoid control circuit.

Action Taken When the DTC Sets

The BCM will not attempt to enable the voltage supply circuit of the automatic transmission shift lock control solenoid until the next key cycle.

Conditions for Clearing the DTC

  1. A current DTC will clear when the malfunction is no longer present and the ignition switch is cycled.
  2. All BCM history codes will clear after 100 ignition cycles with no current codes active during the 100 ignition cycles.

Reference Information

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
  2. «Connector Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-poor)
  4. «Wiring Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Ignition ON, Clear the DTC. Observe the scan tool BCM Brake Applied Output Signal parameter. The parameter should change from ON to OFF when the brake pedal is depressed. If the parameter does not change, refer to «Stop Lamps Malfunction»(/cadillac/dts/i-2005-2011/remont/exterior-lights/#lighting-systems) .
  2. Ignition ON, observe the scan tool BCM Shifter Unlock Command parameter. The parameter should change from ON to OFF when the brake pedal is depressed. If the parameter does not change, replace the BCM.

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the shift lock control solenoid.
  2. Ignition OFF, test for less than 1.0 ohm between the ground circuit terminal A and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Install a test lamp between the ground circuit terminal A and the control circuit terminal B.
  4. Ignition ON, command the scan tool BCM Brake To Shift Control output control ON and OFF. The test lamp should turn ON and OFF as commanded. If the test lamp is always ON, test the control circuit for short to voltage. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. If the circuit tests normal, test or replace the shift lock control solenoid.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Automatic Transmission Shift Lock Actuator Replacement»(/cadillac/dts/i-2005-2011/remont/automatic-trans/#shift-interlock-system)
  2. «Control Module References»(/cadillac/dts/i-2005-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming

Symptoms - Automatic Transmission Shift Lock Control

IMPORTANTThe following steps must be completed before using the symptom tables.
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) 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 (Column Shift)»(/cadillac/dts/i-2005-2011/remont/automatic-trans/#shift-interlock-system__automatic-transmission-shift-lock-control-description) or «Automatic Transmission Shift Lock Control Description and Operation (Floor Shift)»(/cadillac/dts/i-2005-2011/remont/automatic-trans/#shift-interlock-system__automatic-transmission-shift-lock-control-description) .

Visual/Physical Inspection

  1. Inspect for aftermarket devices which could affect the operation of the automatic transmission shift lock control. Refer to «Checking Aftermarket Accessories»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__checking-aftermarket-accessories) .
  2. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections .

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom

  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Shift Lock Control Solenoid Control CircuitB2705 021
Shift Lock Control Solenoid Ground Circuit1
1. Unable to move gearshift lever with brake pedal depressed

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 solenoid is grounded at G300. When the brake pedal is pressed, the body control module (BCM) sends a voltage signal to the shift lock control solenoid through the shift lock solenoid control circuit. This signal mechanically unlocks the shift lever allowing the driver to move the shift lever out of the PARK position.

Schematic Reference

Connector End View Reference

Description and Operation

  1. «Automatic Transmission Shift Lock Control Description and Operation (Column Shift)»(/cadillac/dts/i-2005-2011/remont/automatic-trans/#shift-interlock-system__automatic-transmission-shift-lock-control-description) or «Automatic Transmission Shift Lock Control Description and Operation (Floor Shift)»(/cadillac/dts/i-2005-2011/remont/automatic-trans/#shift-interlock-system__automatic-transmission-shift-lock-control-description)
  2. «Reverse Lockout System Description and Operation»(/cadillac/dts/i-2005-2011/remont/automatic-trans/#shift-interlock-system)

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
  2. «Connector Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-poor)
  4. «Wiring Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for Scan Tool Information

  1. Ignition ON, while pressing the brake pedal, observe the scan tool Brake Applied Output Signal parameter. The reading should be ON with the brake pedal pressed. If not the specified value, refer to «Stop Lamps Malfunction»(/cadillac/dts/i-2005-2011/remont/exterior-lights/#lighting-systems) .
  2. Press the brake pedal, the vehicle operator should be able to move the shifter lever out of the park position.
  1. Ignition OFF, disconnect the harness connector at the shift lock control solenoid.
  2. Ignition OFF, test for less than 1.0 ohm between the ground circuit terminal A and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Install a test lamp between the ground circuit terminal A and the control circuit terminal B.
  4. Ignition ON, command the scan tool BCM Brake To Shift Control output control ON and OFF. The test lamp should turn ON and OFF as commanded. If the test lamp is always ON, test the control circuit for short to voltage. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. If the circuit tests normal, test or replace the shift lock control solenoid.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Automatic Transmission Shift Lock Actuator Replacement»(/cadillac/dts/i-2005-2011/remont/automatic-trans/#shift-interlock-system)
  2. «Control Module References»(/cadillac/dts/i-2005-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Brake Transmission Shift Interlock Solenoid Control Circuit222
Shift Lock Control Solenoid Ignition Voltage22
Shift Lock Control Solenoid Ground Circuit22
Reverse Lockout Solenoid Ignition Voltage11
Reverse Lockout Solenoid Control11
1. Reverse Lockout Malfunction 2. Shift Lock Control Solenoid Malfunction

Shift Lock

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 shift lock solenoid is a 3 wire motor. With the ignition ON battery voltage is supplied to the shift lock control solenoid from the SHFTR SOL fuse. The solenoid is grounded at G304. When the brake pedal is pressed, the body control module (BCM) sends a voltage signal to the shift lock control solenoid through the shift lock solenoid control circuit. This signal mechanically unlocks the shift lever allowing the driver to move the shift lever out of the PARK position.

Reverse Lockout

The reverse lockout system is a safety feature which prevents an inadvertent shift into reverse at speeds above 5 km/h (3 mph). With the ignition ON, battery voltage is supplied directly to the reverse lockout solenoid from the HTD/COOL/IGN3 fuse. At forward speeds above 5 km/h (3 mph), the engine control module (ECM) commands the reverse lockout solenoid ON by grounding the control circuit of the solenoid. This energizes the solenoid and mechanically prevents the shift lever from going from NEUTRAL into the REVERSE position. At forward speeds below 5 km/h (3 mph), the ECM commands the reverse lockout solenoid OFF, de-energizing the solenoid, which allows the shift lever to move into the REVERSE position.

Schematic Reference

Connector End View Reference

Description and Operation

  1. «Automatic Transmission Shift Lock Control Description and Operation (Column Shift)»(/cadillac/dts/i-2005-2011/remont/automatic-trans/#shift-interlock-system__automatic-transmission-shift-lock-control-description) or «Automatic Transmission Shift Lock Control Description and Operation (Floor Shift)»(/cadillac/dts/i-2005-2011/remont/automatic-trans/#shift-interlock-system__automatic-transmission-shift-lock-control-description)
  2. «Reverse Lockout System Description and Operation»(/cadillac/dts/i-2005-2011/remont/automatic-trans/#shift-interlock-system)

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
  2. «Connector Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-poor)
  4. «Wiring Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, while pressing the brake pedal, observe the scan tool Brake Applied Output Signal parameter. The reading should be ON with the brake pedal pressed. If not the specified value, refer to «Stop Lamps Malfunction»(/cadillac/dts/i-2005-2011/remont/exterior-lights/#lighting-systems) .
  2. Press the brake pedal, the vehicle operator should be able to move the shifter lever out of the park position.
  3. With the vehicle moving over 5 km/h (3 mph), the vehicle operator should not be able to move the shift lever into the reverse position.
  1. Ignition OFF, disconnect the harness connector X1 at the automatic transmission shift lever assembly.
  2. Ignition OFF, test for less than 1.0 ohm between the ground circuit terminal C and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal A and ground. If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
  4. While pressing the brake pedal, verify that a test lamp illuminates between the control circuit terminal B and B+. If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance. If all circuits test normal, replace the BCM.
  5. Ignition OFF, connect the harness connector X1 at the automatic transmission shift lever assembly. Disconnect the harness connector X2 at the automatic transmission shift lever assembly.
  6. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal A and ground. If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
  7. Connect a test lamp between the B+ terminal A and the control circuit terminal B.
  8. Command the Reverse Inhibit ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the ECM. If the test lamp is always OFF, test the control circuit for a short to voltage open/high resistance. If the circuit tests normal, replace the ECM.
  9. If all circuits test normal, test or replace the shifter assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Transmission Control Replacement»(/cadillac/dts/i-2005-2011/remont/automatic-trans/#how-to-overhaul-the-automatic-transaxle-4t80-e-removal-installation-service-troubleshooting-diagnosis)
  2. «Control Module References»(/cadillac/dts/i-2005-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM and ECM replacement, setup, and programming

Removal Procedure

  1. Remove the knee bolster bracket. Refer to «Driver Knee Bolster Replacement»(/cadillac/dts/i-2005-2011/remont/exteriorinterior-trim/#instrument-panel-trim-and-console-trim) .
  2. Remove the steering column trim covers.
  3. Disconnect the automatic transmission shift lock control connector.
  4. Use a screwdriver to pry the automatic transmission shift lock control from the steering column support assembly.
  5. Remove the automatic transmission shift lock control from the steering column.

Installation Procedure

  1. Install the automatic transmission shift lock control. Put the column in the NEUTRAL position.
  2. Adjust the automatic transmission shift lock control. Pull the tab (1) out on the block side (2) of the automatic transmission shift lock control. Shift the column into the NEUTRAL position. Press on the adjuster block (2) to compress the internal adjuster spring to disengage the adjuster teeth. Slide the adjuster block (2) as far away from the solenoid as possible. Shift the column into the PARK position. Lock in place by pushing the tab (1) back in.
  3. Inspect the automatic transmission shift lock control.
  4. Reconnect the automatic transmission shift lock control connector.
  5. Install the steering column trim covers.
  6. Install the knee bolster bracket. Refer to «Driver Knee Bolster Replacement»(/cadillac/dts/i-2005-2011/remont/exteriorinterior-trim/#instrument-panel-trim-and-console-trim) .

Automatic Transmission Shift Lock Control Description & Operation (Column Shift)

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 following components

  1. The automatic transmission shift lock solenoid (serviced as the automatic transmission shift lock actuator), as well as the body control module (BCM) and the engine control module (ECM).The shift lock solenoid is located within the steering column assembly with vehicles equipped with column shift.
  2. 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 the brake pedal position.

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.

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

Automatic Transmission Shift Lock Control Description & Operation (Floor Shift)

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 following components

  1. The automatic transmission shift lock solenoid (serviced as the automatic transmission shift lock actuator), as well as the body control module (BCM) and the engine control module (ECM).The shift lock solenoid is located within the floor shift control assembly with vehicles equipped with floor shift.
  2. The BCM controls the voltage supply circuit of the shift lock control solenoid. The following conditions must be before the BCM will supply voltage to the shift lock control solenoid.

The BCM controls the voltage to the shift lock control solenoid through the shift lock control solenoid controlled voltage circuit. The following conditions must be met before the BCM will supply voltage to the shift lock 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 applied according the brake pedal position.

Since the shift lock control solenoid is permanently grounded, the BCM supplies voltage to the automatic transmission shift lock control solenoid, mechanically unlocking the shift lever allowing the driver to move the shift lever out of the PARK position as the solenoid energizes. When the brake pedal is not 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 mechanically locks the shift lever in the PARK position.

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

Reverse Lockout Control (Console Shift Only)

The reverse lockout system is a safety feature which prevents an inadvertent shift into reverse at speeds above 5 km/h (3 mph). The system consists of the following components

  1. The engine control module (ECM).
  2. The reverse lockout solenoid

With the ignition ON, battery voltage is supplied directly to reverse lockout solenoid. At forward speeds above 5 km/h (3 mph), the ECM commands the reverse lockout solenoid ON by grounding the control circuit of the solenoid. This energizes the solenoid and mechanically prevents the shift lever from being moved into the REVERSE position. At forward speeds below 5 km/h (3 mph), the ECM commands the reverse lockout solenoid OFF, de-energizing the solenoid, which allows the shift lever to move into the REVERSE position.

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