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 power liftgate control module (PLGM) 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 PLGM. The latch switches share a common low reference circuit from the PLGM and when the switch contacts close the signal circuit goes low and the PLGM 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 PLGM. 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
System voltage to the liftgate control module must be 9-16 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 status code.

DIAGNOSTIC AIDS
Whenever the PLGM loses power or is disconnected, the ignition must be cycled OFF then ON.

CIRCUIT/SYSTEM VERIFICATION
1. Ignition ON, observe the scan tool Pawl Sw. parameter while opening and closing the liftgate. The reading should change between ACTIVE and INACTIVE.
2. Observe the scan tool Ratchet Sw. parameter while opening and closing the liftgate. The reading should change between ACTIVE and INACTIVE.
3. Observe the scan tool 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 of resistance 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 PLGM.
3. Ignition ON, verify the scan tool 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 PLGM.
4. Ignition ON, verify the scan tool 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 PLGM.
5. Ignition ON, verify the scan tool 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 PLGM.
6. Install a 3A fused jumper wire between the signal circuit terminal 5 and low reference circuit terminal 2. Verify the scan tool Pawl Sw. parameter is ACTIVE.
- If not the specified value, test the signal circuit terminal 5 for a short to voltage or an open/high resistance. If the circuit tests normal, replace the PLGM.
7. Install a 3A fused jumper wire between the signal circuit terminal 6 and low reference circuit terminal 2. Verify the scan tool Ratchet Sw. parameter is ACTIVE.
- If not the specified value, test the signal circuit terminal 6 for a short to voltage or an open/high resistance. If the circuit tests normal, replace the PLGM.
8. Install a 3A fused jumper wire between the signal circuit terminal 4 and low reference circuit terminal 2. Verify the scan tool Sector Sw. parameter is ACTIVE.
- If not the specified value, test the signal circuit terminal 4 for a short to voltage or an open/high resistance. If the circuit tests normal, replace the PLGM.
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
- Programming and Relearning. Programming and Relearning
- Liftgate Actuator Replacement
- Liftgate Calibration Procedure