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PRE-RELEASE

Liftgate Latch Switches Malfunction - DTC B153A

Liftgate Latch Switches Malfunction - DTC B153A

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 Descriptor

DTC B153A 08

Power Liftgate Latch Switches Signal Invalid

Diagnostic Fault Information

Circuit Short to Ground Open/High Resistance Short to Voltage Signal Performance
Liftgate Latch Pawl Switch Signal B153A 08 B153A 08 B153A 08 -
Liftgate Latch Ratchet Switch Signal B153A 08 B153A 08 B153A 08 -
Liftgate Latch Sector Switch Signal B153A 08 B153A 08 B153A 08 -
Liftgate Latch Low Reference - B153A 08 B153A 08 -


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 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

Connector End View Reference

Component Connector End Views

Description and Operation

Liftgate Description and Operation

Electrical Information Reference


• Testing for Intermittent Conditions and Poor Connections

• Circuit Testing

• Wiring Repairs

• Connector Repairs


Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification


1. With the liftgate closed, observe the scan tool Liftgate Latch Pawl, Ratchet, and Sector Switch parameters. Each parameter status should be as listed below:

• Liftgate Latch Pawl Switch parameter - Closed

• Liftgate Latch Ratchet Switch parameter - Closed

• Liftgate Latch Sector Switch parameter - Inactive

2. With the liftgate open, observe the scan tool Liftgate Latch Pawl, Ratchet, and Sector Switch parameters. Each parameter status should be as listed below:

• Liftgate Latch Pawl Switch parameter - Open

• Liftgate Latch Ratchet Switch parameter - Open

• Liftgate Latch Sector Switch parameter - Inactive

3. Sector Switch Test: Close the liftgate allowing the closing motor to pull the liftgate closed. Observe the scantool Liftgate Latch Sector Switch parameter whilst the liftgate is automatically closed. The parameter should change from Inactive to Active then back to Inactive within 10 seconds.


Circuit/System Testing


1. Ignition OFF, disconnect the harness connector at the A23C liftgate latch assembly.

2. Test for less than 30 Ω between the low reference circuit terminal 2 and ground.

3. If greater than the specified range, test the low reference circuit for a short to voltage, or an open/high resistance. If the circuit tests normal, replace the K39 liftgate control module.

4. Ignition ON, verify the scan tool Liftgate Latch Pawl Switch parameter is Closed.

5. If not the specified value, test the signal circuit terminal 5 for a short to ground. If the circuit tests normal, replace the K39 liftgate control module.

6. Install a 3 A fused jumper wire between the signal circuit terminal 5 and the low reference circuit terminal 2. Verify the scan tool Liftgate Latch Pawl Switch parameter is Open.

7. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K39 liftgate control module.

8. Verify the scan tool Liftgate Latch Ratchet Switch parameter is Closed.

9. If not the specified value, test the signal circuit terminal 6 for a short to ground. If the circuit tests normal, replace the K39 liftgate control module.

10. Install a 3 A fused jumper wire between the signal circuit terminal 6 and low reference circuit terminal 2. Verify the scan tool LLiftgate Latch Ratchet Switch parameter is Open.

11. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K39 liftgate control module.

12. Verify the scan tool Liftgate Latch Sector Switch parameter is Inactive.

13. If not the specified value, test the signal circuit terminal 4 for a short to ground. If the circuit tests normal, replace the K39 liftgate control module.

14. Install a 3 A fused jumper wire between the signal circuit terminal 4 and low reference circuit terminal 2. Verify the scan tool Liftgate Latch Sector Switch parameter is Active.

15. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K39 liftgate control module.

16. If all circuits test normal, test or replace the A23C liftgate latch assembly.


Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic repair.


• Liftgate Latch Replacement

• Control Module References for liftgate control module replacement, setup and programming


PRE-RELEASE