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B153A



DTC B153A

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* 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 00
- Liftgate Latch Switch Signal Circuit

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

Any incorrect combination of 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.

Circuit/System Verification

1. Ignition ON, observe the scan tool LGM Latch Pawl Sw. parameter while opening and closing the liftgate. The reading should change between Active and Inactive.
2. Observe the scan tool LGM Latch Ratchet Sw. parameter while opening and closing the liftgate. The reading should change between Active and Inactive.
3. Observe the scan tool LGM Latch Sector Sw. parameter while opening and closing the liftgate. The reading 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 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 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 for a short to ground. If the circuit tests normal, replace the LGM.

6. Install a 3-A 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 3-A 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 3-A 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 after completing the diagnostic procedure. Verification Tests

* Liftgate Actuator Replacement
* Liftgate Calibration Procedure