B153A
DTC B153A
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.
DTC Descriptor
DTC B153A 00
- Liftgate Latch Switch Signal Circuit
DTC B153A 08
- Liftgate Latch Switch Signal Circuit 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 module (LGM) to determine the state of the latch during the process of latching 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 battery voltage through a resistor and monitored within the LGM. The latch switches share a common low reference circuit from the LGM and when the switch contacts close the signal circuit goes low and the LGM determines the switch to be active. The full open switch is a limit switch mounted on the gear motor assembly alongside the swing arm gear. The full open switch signal circuit is supplied battery voltage through a resistor and monitored within the LGM. When the liftgate reaches the full open position, the switch signal circuit is closed to the low reference circuit and the signal circuit voltage goes low.
Conditions for Running the DTC
The system voltage is 9-18 volts.
Conditions for Setting the DTC
B153A 00
The LGM detects a fault in any of the following switch signal circuits:
* Ratchet switch
* Pawl switch
* Sector switch
B153A 08
Any incorrect combination of signals from the following switch inputs:
* Ratchet switch
* Pawl switch
* Sector switch
Action Taken When the DTC Sets
* Power open will be disabled.
* 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
Important: Before testing can be performed the liftgate must be opened. Refer to Opening the Liftgate Without Electrical Power () for the appropriate procedure.
Whenever the LGM loses power or is disconnected, the ignition must be cycled OFF then ON in order to reactivate the LGM.
Reference Information
Schematic Reference
Liftgate Schematics (Liftgate Schematics)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
Rear Hatch/Gate Description and Operation ()
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Verification
1. Ignition ON, observe the scan tool LGM Latch Pawl Sw. parameter while opening and closing the liftgate. The parameter should change between Active and Inactive.
2. Observe the scan tool LGM Latch Ratchet Sw. parameter while opening and closing the liftgate. The parameter should change between Active and Inactive.
3. Observe the scan tool LGM Latch Sector Sw. parameter while opening and closing the liftgate. The parameter should change between Active and Inactive.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the liftgate latch assembly.
2. Ignition OFF, test for less than 1.0 ohm between the low reference circuit terminal 2 and ground.
• If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the LGM.
3. Ignition ON, verify the scan tool LGM Latch Pawl Sw. parameter is Inactive.
• If not the specified value, test the signal circuit terminal 5 for a short to ground. If the circuit tests normal, replace the LGM.
4. Verify the scan tool LGM Latch Ratchet Sw. parameter is Inactive.
• If not the specified value, test the signal circuit terminal 6 for a short to ground. If the circuit tests normal, replace the LGM.
5. Verify the scan tool LGM Latch Sector Sw. parameter is Inactive.
• If not the specified value, test the signal circuit terminal 4 for a short to ground. If the circuit tests normal, replace the LGM.
6. Install a 3A fused jumper wire between the signal circuit terminal 5 and low reference circuit terminal 2. Verify the scan tool LGM Latch Pawl Sw. parameter is Active.
• 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 LGM.
7. Install a 3A fused jumper wire between the signal circuit terminal 6 and low reference circuit terminal 2. Verify the scan tool LGM Latch Ratchet Sw. parameter is Active.
• 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 LGM.
8. Install a 3A fused jumper wire between the signal circuit terminal 4 and low reference circuit terminal 2. Verify the scan tool LGM Latch Sector Sw. parameter is Active.
• 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 LGM.
9. If all circuits test normal, test or replace the liftgate latch assembly.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Liftgate Actuator Replacement ()
* Control Module References (Programming and Relearning) for LGM replacement, setup and programming