Circuit/System Verification

WARNING: This page is about a different car, the 2018 Buick Envision. However, it is still accessible from the selected car via links, so may be relevant.

Ignition ON.
Verify the K39 Liftgate Control Module is programmed with the latest and correct software.
- If the software is not the latest or is not the correct software
  Refer to Control Module References for liftgate control module replacement, programming and setup.
- Go to next step: If the software is the latest and is correct
Verify the K39 Liftgate Control Module does not have any current DTCs set.
- If the K39 Liftgate Control Module has current DTCs set
  Refer to Diagnostic Trouble Code (DTC) List - Vehicle
- Go to next step: If the K39 Liftgate Control Module does not have any current DTCs set
Verify DTC B2494 or B153F is not set as a history DTC.
- DTC B2494 is set only as history
  Refer to Liftgate Release Switch Replacement (Door)
- DTC B153F is set only as history
  Refer to Liftgate Side Sensor Replacement
- Go to next step: If the K39 Liftgate Control Module does not have any history DTCs set
Verify the scan tool Liftgate Mode Switch parameter changes from Off to 3/4 to Maximum while rotating the S45B Liftgate Control Switch-Interior.
- If the parameter does not change
  Refer to DTC B396C or B396D - Liftgate Interior Release Open/Close Switch Malfunction .
- Go to next step: If the parameter changes
Verify the scan tool Liftgate Front Control Switch parameter changes between Inactive and Active when pressing the S45B Liftgate Control Switch-Interior.
- If the parameter does not change
  Refer to DTC B396C or B396D - Liftgate Interior Release Open/Close Switch Malfunction .
- Go to next step: If the parameter changes
Liftgate Closed, verify the scan tool Liftgate Latch Pawl Switch, Liftgate Latch Ratchet Switch, and Liftgate Latch Sector Switch parameters are as listed below:
- Liftgate Latch Pawl Switch parameter Close
- Liftgate Latch Ratchet Switch parameter Close
- Liftgate Latch Sector Switch parameter Inactive
- If any of the parameters are not as listed
  Refer to DTC B2494 - Liftgate Handle Switch Malfunction .
- Go to next step: If the parameters are as listed
Verify the scan tool Liftgate Handle Switch parameter changes between Active and Inactive when pressing the S46B Liftgate Unlatch Switch.
- If the parameter does not change
  Refer to DTC B2494 - Liftgate Handle Switch Malfunction .
- Go to next step: If the parameter changes
Verify the liftgate will release and smoothly power open when commanding Liftgate Open with a scan tool.
- If the liftgate does not release
  Refer to Liftgate Latch Release/Cinch Malfunction
- If the liftgate releases but does not open
  Refer to Power Liftgate Malfunction
- If the liftgate releases but performs an erratic power open/close motion
  Refer to Power Liftgate Malfunction
- Go to next step: If the liftgate smoothly opens
Liftgate Open, verify that the liftgate will remain at or near the full open position and does not slowly close.
- If the liftgate will not remain open or begins to slowly close
  Refer to Liftgate Strut Replacement .
- Go to next step: If the liftgate remains in the full open position
Liftgate Open, verify the scan tool Liftgate Secondary Obstacle Detection parameter is between 3V-3.5V.
- If not between 3V-3.5V
  Refer to DTC B153F - Liftgate Object Sensor Malfunction .
- Go to next step: If between 3V-3.5V
Liftgate Open, verify the scan tool Liftgate Latch Pawl Switch, Liftgate Latch Ratchet Switch, and Liftgate Latch Sector Switch parameters are as listed below
- Liftgate Latch Pawl Switch parameter Open
- Liftgate Latch Ratchet Switch parameter Open
- Liftgate Latch Sector Switch parameter Inactive
- If any of the parameter are not as listed
  Refer to DTC B153A - Liftgate Latch Switches Malfunction .
- Go to next step: If the parameters are as listed
Verify the scan tool Liftgate Rear Close Switch parameter changes between Active and Inactive when pressing the B70 Liftgate Close Switch.
- If the parameter does not change
  Refer to DTC B396E - Liftgate Close Switch Malfunction .
- Go to next step: If the parameter changes
Verify the liftgate will smoothly power close when commanding Liftgate Close with a scan tool.
- If the liftgate does not power close and sets DTC B396A
  Refer to DTC B396A - Liftgate Motor Power Open/Close Malfunction
- If the liftgate performs an erratic open/close motion and does not set a DTC
  Refer to Power Liftgate Malfunction
- Go to next step: If the liftgate smoothly power closes

NOTE:

Refer to the owner's manual for the location of the kick sensors prior to performing the kicking motion

If equipped, liftgate Closed, with the keyless entry transmitter within 3 feet (1 meter) of the liftgate, activate the handsfree liftgate release system with a kicking motion of a foot under the rear fascia. The tail lamps will flash 3 times if the liftgate handsfree sensors detect the motion.
- If the tail lamps do not flash
  Refer to Liftgate Handsfree Sensor Malfunction
- Go to next step: If the tail lamps flash
All OK.