Component Tests and General Diagnostics

POWER LIFTGATE SYSTEM

In order to obtain conclusive testing of the power liftgate system, the Controller Area Network (CAN) data bus, and all of the electronic modules that provide inputs to, or receive outputs from the power liftgate system components must be checked. Any diagnosis of the power liftgate system should begin with, the use of a scan tool and the appropriate diagnostic service information.

Refer to the appropriate wiring information for complete circuit schematic or connector pin-out information.

NOTE: Before any testing of the power liftgate system is attempted, the battery should be fully-charged.

Following are quick reference diagnostic tables to help when diagnosing and testing the power liftgate system.

SYMPTOM DRIVEN POWER LIFTGATE SYSTEM DIAGNOSIS TABLE


















POWER LIFTGATE SYSTEM CONTROL PARAMETERS

The power liftgate system is designed with a number of control parameters, which are conditions that must be fulfilled to allow operation. These control parameters are listed below:

- The Power Liftgate module will inhibit operation of the power liftgate in extreme temperatures. These temperatures will be approximately -22° F (-30° C) and 149° F (65° C). The pinch sensor/thermistor assembly on the right side of the liftgate monitors the temperature.
- The vehicle's transmission must be in park or neutral for the power liftgate to operate.
- The vehicle's speed must be zero for the power liftgate to operate.
- The vehicle's electrical system voltage must be within specification for the power liftgate system to operate. A low-voltage cut-off is built into the power liftgate system to prevent the vehicle's battery from discharging to the point were the vehicle cannot be operated.
- If the vehicle's ignition switch is in the "START" position, the power liftgate system will not initiate a power cycle.
- If the vehicle's ignition switch is moved to the "START" position during a power cycle, the power liftgate will pause.
- If the vehicle is locked, the outside handle will not release the latch. The key fob and overhead switch will work for power open or close cycles.
- If the vehicle's theft alarm is armed, the overhead switch will not open the liftgate; however the key fob will work.
- If a liftgate pinch sensor is activated during a power close, the liftgate will reverse direction. If a pinch sensor is already active the power liftgate will not initiate a power close. A pinch activation during latch cinch will stop the cinch operation.
- If something sufficiently impedes liftgate travel, the power liftgate will detect an obstacle and reverse direction, traveling to full open or closed.
- If multiple obstacles are detected during the same power open or close cycle, the liftgate will abort that power cycle and go into full manual operation.
- The power liftgate components are protected by the power liftgate fuse. If the fuse is blown, the power liftgate will not function [1][2]Fuse Locations/Types.
- If severe Diagnostic Trouble Codes (DTC's) are stored in the power liftgate control module the system may not operate. If power liftgate DTC's are present, refer to Power Liftgate Testing.

POWER LIFTGATE INPUT - OUTPUT TABLE










POWER LIFTGATE SYSTEM INHIBIT MONITORS

The following is a list of inhibit monitors as observed by an appropriate scan tool.

POWER LIFTGATE SYSTEM INHIBIT MONITORS TABLE