Circuit/System Verification
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2012 GMC Yukon XL, 2012 GMC Yukon, 2012 Chevrolet Tahoe, 2012 Chevrolet Suburban, and 2012 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
- Verify the liftgate control module is programmed with the latest software.
- If the software is not the latest, program the liftgate control module with the latest software. Refer to Control Module References for liftgate control module replacement, programming and setup.
- Verify the liftgate control module does not have any current DTCs set.
- If the liftgate control module has current DTCs set, refer to Diagnostic Trouble Code (DTC) List - Vehicle .
- Verify DTC B2494 or B153F is not set as a history DTC.
- If DTC B2494 is set only as history, replace the liftgate control switch-exterior, refer to Liftgate Release Switch Replacement (Except Avalanche and Escalade EXT) .
- If DTC B153F is set only as history, replace both liftgate object sensors, refer to Liftgate Side Upper Sensor Replacement (Except Avalanche and EXT Escalade) .
- Verify the scan tool LGM Disable Switch parameter changes from Inactive to Active pressing and depressing the liftgate Enable/Disable button on the interior liftgate control switch.
- If the parameter does not change, refer to Liftgate Interior Release Open/Close Switch Malfunction - DTC B396C or B396D .
- Place the interior liftgate control switch to the Disable position.
- Verify the scan tool LGM Front Control Switch parameter changes between Inactive and Active while pressing and releasing the interior liftgate control switch.
- If the parameter does not change, refer to Liftgate Interior Release Open/Close Switch Malfunction - DTC B396C or B396D .
- With the liftgate closed, observe the scan tool Liftgate Latch Pawl, Ratchet, and Sector Switch parameters. Each parameter status should be as listed below:
- LGM Latch Pawl Sw. parameter - Inactive
- LGM Latch Ratchet Sw. parameter - Inactive
- LGM Latch Sector Sw. parameter - Inactive
- If not the specified value, refer to Liftgate Latch Switches Malfunction - DTC B153A .
- Observe the scan tool Liftgate Handle Sw. Status parameter while pressing and releasing the liftgate handle switch. The value should change between Active and Inactive as the switch is pressed and released.
- If the parameter does not change, refer to Liftgate Handle Switch Malfunction - DTC B2494 .
- Using either the power door lock switches or the keyless entry transmitter, LOCK all doors then UNLOCK all doors. This will set the liftgate module door lock status to unlock.
- Verify the liftgate will manually open.
- If the liftgate does not manually open, refer to Liftgate Latch Release/Cinch Malfunction - DTC B2495 .
- With the liftgate open, verify the scan tool Object Detection Sensor Status parameter is 3-3.5 V.
- If not within the specified range, refer to Liftgate Object Sensor Malfunction - DTC B153F .
- With the liftgate open, verify the scan tool Liftgate Latch Pawl, Ratchet, and Sector Switch parameters are as listed below:
- LGM Latch Pawl Sw. parameter - Active
- LGM Latch Ratchet Sw. parameter - Active
- LGM Latch Sector Sw. parameter - Inactive
- If not the specified value, refer to Liftgate Latch Switches Malfunction - DTC B153A .
- Observe the scan tool Liftgate Handle Sw. Status parameter while pressing and releasing the liftgate close switch. The value should change between Active and Inactive as the switch is pressed and released.
- If the parameter does not change, refer to Liftgate Handle Switch Malfunction - DTC B2494 .
- Observe the scan tool LGM Full Open Switch parameter while manually opening and closing the liftgate. The parameter should change between Active and Inactive as the liftgate opens and closes.
- If the value does not change, refer to Liftgate Full Open Switch Malfunction - DTC B153B .
- Verify while manually opening and closing the liftgate is in proper aligned with the body bumpers, wedges and striker and there is no binding.
- Verify that the liftgate will remain at or near the full open position and does not drop down.
- If the liftgate will not remain open or drops, refer to Power Liftgate Sags When Open or Slowly Closes .
- Verify the scan tool LGM Latch Sector Sw. parameter changes from Inactive to Active then back to Inactive within 10 seconds while the liftgate is being automatically cinched closed.
- If the liftgate cinches close and the parameter does not momentarily change states while cinching, refer to Liftgate Latch Switches Malfunction - DTC B153A .
- If the liftgate does not cinch close, refer to Liftgate Latch Release/Cinch Malfunction - DTC B2495 .
- Liftgate open, select the Enable position on the interior liftgate control switch then activate the power close function. Verify the scan tool LGM Clutch Actuator Cmd. changes from Inactive to Active
- If the parameter does not change, refer to Liftgate Motor Clutch Malfunction - DTC B396B .
- Activate the power close function of the liftgate.
- If the liftgate does not power close, refer to Liftgate Motor Power Open/Close Malfunction - DTC B396A .
- Liftgate closed, activate the power open function. Verify the liftgate power opens.
- If the liftgate does not power open, refer to Liftgate Motor Power Open/Close Malfunction - DTC B396A .
- Verify the liftgate has not been auto reversing un-expectedly.
- If the liftgate has been auto reversing, check both liftgate object sensors for interference or deformity.