B153B

DTC B153B

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 Descriptors
DTC B153B 02
- Liftgate Open Switch Signal Circuit Short to Ground

DTC B153B 05
- Liftgate Open Switch Signal Circuit Short to Short to Battery or Open

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 B153B 02 will set when the LGM detects a short to ground in the full open switch signal circuit.
* DTC B153B 08 will set when the LGM detects a short to voltage or an open/high resistance in the full open switch signal circuit.

Action Taken When the DTC Sets

The power liftgate system will be disabled.

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

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

Circuit/System Testing

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
* Control Module References for LGM replacement, setup, and programming. Programming and Relearning