B153A
Liftgate Latch Switches Malfunction - DTC B153A
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 Descriptor
DTC B153A 08
- Power Liftgate Latch Switches Signal Invalid
Diagnostic Fault Information
Circuit/System Description
The ratchet, pawl, and sector switches are part of the liftgate latch assembly and are used by the liftgate control module to determine the state of the latch during the process of cinching or unlatching. The ratchet and pawl switches will be inactive when the primary and secondary latches are latched, and the sector switch will be active during the power cinch function. Each of the latch switch signal circuits are supplied signal through a resistor and monitored within the liftgate control module. The latch switches share a common low reference circuit from the liftgate control module and when the switch contacts close the signal circuit goes low and the liftgate control module determines the switch to be active.
Conditions for Running the DTC
The system voltage is 9-16 V.
Conditions for Setting the DTC
When the liftgate control module detects an open/high resistance in the ratchet, pawl, and/or the sector signal circuit, an open/high resistance in the liftgate latch low reference circuit, or any incorrect combination of signals from the following switch inputs:
* Ratchet switch
* Sector switch
* Pawl switch
Action Taken When the DTC Sets
* The liftgate may not power open or power close.
* The latch may be inoperative or not function normally.
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.
* DTC B153A may be set when the vehicle is driven while the liftgate is open, as when the owner transports a large package in the rear of the vehicle. The DTC will become history after the liftgate is closed and does not affect normal liftgate operation
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 Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON.
2. Verify the scan tool Liftgate Latch Pawl Switch parameter changes between Open and Closed when opening and closing the liftgate
• If the parameter does not change
Refer to Circuit/System Testing.
• If the parameter changes
3. Verify the scan tool Liftgate Latch Ratchet Switch parameter changes between Open and Closed when opening and closing the liftgate
• If the parameter does not change
Refer to Circuit/System Testing.
• If the parameter changes
4. Liftgate open, verify the scan tool Liftgate Latch Sector Switch parameter changes from Inactive to Active to Inactive while the liftgate is being automatically cinched closed
• If the parameter does not change
Refer to Circuit/System Testing.
• If the parameter changes
5. All OK.
Circuit/System Testing
1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the A23C liftgate latch assembly. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 10 ohms between the low reference circuit terminal 2 and ground.
• If 10 ohms or greater
1. Ignition OFF.
2. Test for less than 2 ohms in the low reference 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 low reference connection.
• If less than 10 ohms
3. Ignition ON.
4. Verify the scan tool Liftgate Latch Pawl Switch parameter is Closed.
• If not Closed
1. Ignition OFF, disconnect the harness connector at the K39 liftgate control module.
2. Test for infinite resistance between the signal circuit terminal 5 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 Closed
5. Install a 3 A fused jumper wire between the signal circuit terminal 5 and the low reference circuit terminal 2.
6. Verify the scan tool Liftgate Latch Pawl Switch parameter is Open
• If not Open
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 terminal 5 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 Open
7. Verify the scan tool Liftgate Latch Ratchet Switch parameter is Closed.
• If not Closed
1. Ignition OFF, disconnect the harness connector at the K39 liftgate control module.
2. Test for infinite resistance between the signal circuit terminal 6 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 Closed
8. Install a 3 A fused jumper wire between the signal circuit terminal 6 and the low reference circuit terminal 2.
9. Verify the scan tool Liftgate Latch Ratchet Switch parameter is Open
• If not Open
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 terminal 6 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 Open
10. Verify the scan tool Liftgate Latch Sector 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
11. Install a 3 A fused jumper wire between the signal circuit terminal 4 and the low reference circuit terminal 2.
12. Verify the scan tool Liftgate Latch Sector 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 terminal 4 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
13. Test or replace the A23C liftgate latch assembly.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic repair.
* Liftgate Latch Replacement Service and Repair
* Control Module References Control Module References for the liftgate control module replacement, setup and programming