B396C
Liftgate Interior Release Open/Close Switch Malfunction - DTC B396C or B396D
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptors
DTC B396C 08
- Liftgate Mode Switch Circuit Performance Signal Invalid
DTC B396D 02
- Front Liftgate Actuator Switch Circuit Short To Ground
Diagnostic Fault Information
Circuit/System Description
The interior liftgate rotary control switch contains 3 resistors which are in series for the liftgate mode, depending upon which position is selected will determine which combination of resistors are used. The liftgate module monitors the voltage level in the liftgate mode signal circuit, as each mode is selected, the voltage within the signal circuit incrementally drops. It is this method the liftgate module will determine if mode switch is in the manual mode, garage mode or the maximum open mode.
The interior liftgate control switch has of a push button switch to command the liftgate to open and close. The liftgate module monitors the voltage level on the open/close signal circuit, when the switch is not being pressed the voltage level is at the system voltage. When the switch is pressed a contact within the interior liftgate control switch closes providing a ground path for the signal circuit causing the voltage level to drop to near zero volts. The liftgate module will detect the voltage drop and will then command the liftgate to open or close depending upon the current state of the liftgate at the time the switch is pressed.
Conditions for Running the DTC
The system voltage is 9-16 V.
Conditions for Setting the DTC
B396C 08
The liftgate control module detects an out of range condition in the mode switch signal circuit.
B396D 02
The liftgate control module detects a short to ground in the rear liftgate open/close switch signal circuit for greater than 60 seconds.
Action Taken When the DTC Sets
B396C 08
The manual mode function and the garage mode function will be inoperative.
B396D 02
The liftgate module will ignore the switch input from the interior liftgate control switch and the liftgate operations will only be available from the liftgate switches located on the liftgate panel or by an open or close request from the remote control keyless entry module.
Conditions for Clearing the DTC
* The DTC will be current for as long as the fault is present.
* When the fault is no longer present, the DTC will be a history DTC.
* A history DTC will clear after 50 ignition cycles.
Diagnostic Aids
* If the liftgate will not release from the closed position, refer to Opening the Liftgate Without Electrical Power Service and Repair for the appropriate procedure
* Whenever the liftgate control module loses power or is disconnected, the ignition must be cycled OFF then ON in order to reactivate the liftgate control module.
Reference Information
Schematic Reference
Liftgate Schematics Liftgate Schematics
Connector End View Reference
Component Connector End Views Sunshade - Left Front
Description and Operation
Liftgate Description and Operation Liftgate
Electrical Information Reference
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Circuit Testing Circuit Testing
* Wiring Repairs Wiring Repairs
* Connector Repairs Connector Repairs
Scan Tool Reference
Control Module References Programming and Relearning for scan tool information
Circuit/System Verification
1. Ignition ON.
2. Verify the scan tool Liftgate Front Control Switch parameter changes between Inactive and Active when pressing the liftgate control switch-interior.
• If the parameter does not change
Refer to Circuit/System Testing - Open/Close Switch Circuit Test.
• If the parameter changes
3. Verify the scan tool Liftgate Mode Switch is between 125 counts and 350 counts and changes to 245 counts while rotating the liftgate control switch-interior.
• If not between 125 counts and 350 counts or does not change
Refer to Circuit/System Testing - OFF/ 3/4 position/MAX Switch Circuit Test.
• If between 125 counts and 350 counts and changes
4. All OK.
Circuit/System Testing
Open/Close Switch Circuit Test
1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the S45B liftgate control switch-interior. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 10 ohms between the ground circuit terminal 1 and ground.
• If 10 ohms or greater
1. Ignition OFF.
2. Test for less than 2 ohms in the ground circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, repair the open/high resistance in the ground connection.
• If less than 10 ohms
3. Ignition ON.
4. Verify the scan tool Liftgate Front Control Switch parameter is Inactive.
• If not Inactive
1. Ignition OFF, disconnect the harness connector at the K39 liftgate control module.
2. Test for infinite resistance between the signal circuit terminal 4 and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the K39 liftgate control module.
• If Inactive
5. Install a 3 A fused jumper wire between the signal circuit terminal 4 and the ground circuit terminal 1.
6. Verify the scan tool Liftgate Front Control Switch parameter is Active.
• If not Active
1. Ignition OFF, disconnect the harness connector at the K39 liftgate control module, ignition ON.
2. Test for less than 1 V between the signal circuit and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V
3. Test for less than 2 ohms in the signal circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K39 liftgate control module.
• If Active
7. Test or replace the S45B liftgate control switch-interior.
OFF/ 3/4 position/MAX Switch Circuit Test
1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the S45B liftgate control switch-interior, ignition ON.
2. Verify the scan tool Liftgate Mode Switch parameter is greater than 300 counts.
• If 300 counts or less
1. Ignition OFF, disconnect the harness connector at the K39 liftgate control module.
2. Test for infinite resistance between the signal circuit terminal 3 and ground
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the K39 liftgate control module
• If greater than 300 counts
3. Install a 3 A fused jumper wire between the signal circuit terminal 3 and the ground circuit terminal 1.
4. Verify the scan tool Liftgate Mode Switch parameter is less than 5 counts.
• If 5 counts or greater
1. Ignition OFF, disconnect the harness connector at the K39 liftgate control module.
2. Test for less than 2 ohms in the signal circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K39 liftgate control module
• If less than 5 counts
5. Test or replace the S45B liftgate control switch-interior.
Component Testing
1. Ignition OFF, disconnect the harness connector at the S45B liftgate control switch-interior.
2. Test for infinite resistance between the signal terminal 4 and the ground terminal 1 with the switch in the open position.
• If less than infinite resistance
Replace the S45B liftgate control switch-interior.
• If infinite resistance
3. Test for less than 3 ohms between the signal terminal 4 and the ground terminal 1 with the switch in the closed position.
• If 3 ohms or greater
Replace the S45B liftgate control switch-interior.
• If less than 3 ohms
4. All OK
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Rear Compartment Lid Release Switch Replacement Rear Compartment Lid Release Switch Replacement
* Control Module References Programming and Relearning for the liftgate control module replacement, programming and setup