Circuit 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.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B2705 Gearshift Unlock Circuit
This vehicle has DTCs which include DTC Symptoms. For more information on DTC Symptoms, refer to DTC Symptom Description .
DTC Symptom | DTC Symptom Descriptor |
|---|---|
02 | Short to Ground |
05 | Short to Battery or Open |
Conditions for Running the DTC
| • | The ignition switch is in the ON position. |
| • | The brake pedal is pressed. |
| • | The transmission is in the PARK position. |
Conditions for Setting the DTC
B2705 02
Sets if there is a short to ground in the automatic transmission shift lock control solenoid control circuit.
B2705 05
Sets if there is an open or short to voltage 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. |
| • | The BCM stores DTC B2705 in memory. |
Conditions for Clearing the DTC
| • | A current DTC B2705 will clear when the malfunction is no longer present and the ignition switch is cycled. |
| • | All BCM history codes will clear after 100 ignition cycles with no current codes active during the 100 ignition cycles. |
| • | A scan tool may be used to clear the DTC. |
Diagnostic Aids
| • | If the automatic transmission shift lock control circuit is shorted to ground, the automatic transmission shift lock control solenoid will be inoperative. The vehicle will shift out of PARK without pressing the brake pedal. |
| • | Perform the tests while wiggling the wires and connectors. This may often cause an intermittent malfunction to appear. Refer to Testing for Intermittent Conditions and Poor Connections . |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
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.
-
This step tests for a good ground at the ground circuit of the automatic transmission shift lock control solenoid.
-
This step verifies that the BCM is providing battery voltage to the automatic transmission shift lock control solenoid.
-
This step tests if battery voltage is constantly being applied to the automatic transmission shift lock control solenoid.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Shift Lock Control Schematics Connector End View Reference: Shift Lock Control Connector End Views | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |
Does the automatic transmission shift lock control solenoid turn ON and OFF with each command? | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 3 | |
Does the test lamp illuminate? | Go to Step 4 | Go to Step 10 | |
Does the test lamp turn ON and OFF with each command? | Go to Step 8 | Go to Step 5 | |
Does the test lamp remain illuminated? | Go to Step 6 | Go to Step 7 | |
6 | Test 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 13 | Go to Step 9 |
7 | Test 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 13 | Go to Step 9 |
8 | 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 13 | Go to Step 11 |
9 | Inspect 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 13 | Go to Step 12 |
10 | Repair 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 | -- |
11 | Replace the automatic transmission shift lock control solenoid. Refer Transmission Control Replacement . Did you complete the replacement? | Go to Step 13 | -- |
12 | Replace the BCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 13 | -- |
13 |
Does the DTC reset? | Go to Step 2 | System OK |
Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptors
DTC B2705 02: Gearshift Unlock Circuit Short to GroundDTC B2705 05: Gearshift Unlock Circuit Short to Battery or Open
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Shift Lock Control Solenoid Voltage Supply Circuit | -- | B2705 05 | B2705 05 | -- |
Shift Lock Control Solenoid Ground Circuit | B2705 02 | -- | -- | -- |
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
| • | The ignition switch is in the ON position. |
| • | The brake pedal is pressed. |
| • | The transmission is in the PARK position. |
Conditions for Setting the DTC
The engine control module (ECM)/powertrain control module (PCM) detects a system voltage below 10 volts for 5 seconds.
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. |
| • | The BCM stores DTC B2705 in memory. |
Conditions for Clearing the DTC
| • | A current DTC B2705 will clear when the malfunction is no longer present and the ignition switch is cycled. |
| • | All BCM history codes will clear after 100 ignition cycles with no current codes active during the 100 ignition cycles. |
Diagnostic Aids
| • | if the automatic transmission shift lock control circuit is shorted to ground, the automatic transmission shift lock control solenoid will be inoperative. The vehicle will shift out of PARK without pressing the brake pedal. |
| • | Perform the tests while wiggling the wires and connectors. This may often cause an intermittent malfunction to appear. |
Reference Information
Schematic Reference
Connector End View Reference
Shift Lock Control Connector End Views
Description and Operation
Automatic Transmission Shift Lock Control Description and Operation
Electrical Information Reference
Scan Tool Reference
Circuit/System Verification
Clear the DTC and verify that the brake pedal has to be pressed so that the transmission can be shifted out of the PARK position.
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the shift lock control solenoid.
- Ignition OFF, test for less than 1.0 ohm of resistance between the ground circuit terminal 3 and ground.
- Ignition ON and the engine OFF, command the Brake To Shift Control output control ON and OFF. The automatic transmission shift lock control solenoid should turn ON and OFF and allow the transmission to be shifted out of the PARK position.
- Ignition ON and the engine OFF, 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. With the brake pedal applied, the test lamp should illuminate.
| ⇒ | If greater than the specified range, test the ground circuit for an open. If the circuit tests normal, replace the shift lock control solenoid. |
| ⇒ | If unable to shift out of PARK, test for an open or short to ground in the control circuit. |
| ⇒ | If test lamp does not illuminate, replace the shift lock control solenoid. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
