Diagnostic Aids

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2011 GMC Yukon XL, 2011 GMC Yukon, 2011 Chevrolet Tahoe, 2011 Chevrolet Suburban, and 2011 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

Before testing can be performed, the liftgate must be opened. Refer to Opening the Liftgate Without Electrical Power for the appropriate procedure.

Power liftgate function will only be allowed if certain operating criteria are met. Any of the following may cause the power liftgate not to function:

After a power loss of the low current battery supply until the ignition is cycled.
Vehicle is not in park.
Engine cranking is present.
Ambient temperature at the LGM must be within -17 to +80°C (+1 to +176°F).
Liftgate motor excess current is detected.
System voltage is out of range.
A DTC is set that disables power liftgate functionality.
The liftgate is locked when attempting to open from exterior handle.

The LGM also receives input from 2 pressure sensing object detection sensors. If either of these sensors indicates an object may be pinched as the liftgate is brought to the closed position, the liftgate will reverse direction and power close operation will be suspended until the pressure against the sensor is released.

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

Certain SIR DTCs will make the power liftgate inoperative. Correct any SIR concern first before performing any extensive power liftgate diagnostics.