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 08
- Liftgate Latch Switch Signal Circuit Signal Invalid
Diagnostic Fault Information
Circuit/System Description
The ratchet, pawl, and sector switches are part of the latch motor assembly and are used by the liftgate control module (LGM) to determine the state of the latch during the process of latching or unlatching. 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. For more detailed information concerning power liftgate operation refer to Liftgate Description and Operation.
Conditions for Running the DTC
Battery voltage must be between 9-16 volts.
Conditions for Setting the DTC
DTC B153A 08 will set when the LGM detects signal mismatches from any of the following switches:
* Full open switch
* Pawl switch
* Ratchet switch
* Sector switch
Actions Taken When the DTC Sets
The power liftgate system may be inoperative or function incorrectly.
Conditions for Clearing the DTC
* The condition responsible for setting the DTC no longer exists.
* You issue a scan tool CLEAR DTCs command.
Diagnostic Aids
* A liftgate latch open switch or ajar switch stuck in the open or closed position will cause DTC B153A 08 to set.
* Whenever the LGM 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.
• If the reading does not change as the liftgate is opened and closed, refer to Liftgate Latch Switch Signal Malfunction.
2. Observe the scan tool Ratchet Sw. parameter while opening and closing the liftgate. The reading should change between ACTIVE and INACTIVE.
• If the reading does not change as the liftgate is opened and closed, refer to Liftgate Latch Switch Signal Malfunction.
3. Observe the scan tool Sector Sw. parameter while opening and closing the liftgate. The reading should change between ACTIVE and INACTIVE.
• If the reading does not change as the liftgate is opened and closed, refer to Liftgate Latch Switch Signal Malfunction.
4. Observe the scan tool Full Open Sw. parameter while opening and closing the liftgate. The reading should change between ACTIVE and INACTIVE.
• If the reading does not change as the liftgate is opened and closed, refer to Liftgate Full Open Switch Signal Malfunction.
Circuit/System Testing
Liftgate Latch Switch Signal Malfunction
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 LGM.
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 LGM.
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 LGM.
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 LGM.
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 LGM.
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 LGM.
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 LGM.
9. If all circuits test normal, test or replace the liftgate latch assembly.
Liftgate Full Open Switch Signal Malfunction
1. Ignition OFF, disconnect the C3 harness connector at the LGM.
2. Ignition ON, verify the scan tool Full Open Sw. parameter is INACTIVE.
• If not the specified value, replace the LGM.
3. Reconnect the C3 harness connector at the LGM.
4. Open the liftgate and verify the scan tool Full Open 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, test the low reference circuit terminal 6 for an open/high resistance. If the circuits tests normal, test or replace the liftgate motor assembly.
5. Close the liftgate and verify the scan tool Full Open 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, test or replace the liftgate motor assembly.
6. If all circuits test normal, replace the LGM.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests
* Power Liftgate Motor Replacement
* Liftgate Close Actuator Motor Control Module Replacement
* Control Module References for LGM replacement, setup, and programming. Programming and Relearning