Component Tests and General Diagnostics
DIAGNOSIS AND TESTING
NOTE: Before any testing of the power liftgate system is attempted, the battery should be fully-charged.
The latch, the sensors, the switches and the hard wired circuits between components related to the power liftgate system may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. The wiring information includes wiring diagrams, proper wire and connector repair procedures, details of wire harness routing and retention, connector pin out information and location views for the various wire harness connectors, splices and grounds.
However, conventional diagnostic methods will not prove conclusive in the diagnosis of the electronic controls or communication between modules and other devices that provide some features of the power liftgate system. The most reliable, efficient, and accurate means to diagnose the power liftgate system or the electronic controls and communication related to power liftgate system operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.
Following are quick reference diagnostic tables to help when diagnosing and testing the power liftgate system.
SYMPTOM DRIVEN POWER LIFTGATE SYSTEM DIAGNOSIS
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 (PLGM) will inhibit operation of the power liftgate in extreme ambient temperatures. These temperatures are at or below about -30° C (-22° F) and at or above about 65° C (149° F). The pinch sensor/thermistor assembly on the right side of the liftgate monitors the ambient temperature.
- The transmission must be in the Park (P) or Neutral (N) positions for the power liftgate system to operate.
- The vehicle speed input must be zero (0) for the power liftgate system to operate.
- The electrical system voltage must be within minimum and maximum specifications for the power liftgate system to operate. A low-voltage cut off is built into the power liftgate system to prevent the battery from discharging to the point where the vehicle cannot be operated.
- If the ignition switch is in the Start position, the power liftgate system will not initiate a power cycle.
- If the ignition switch is moved to the Start position during a power cycle, the power liftgate will pause.
- If the vehicle is locked, the exterior liftgate handle will not release the latch. The FOB with Integrated Key (FOBIK) and the overhead console switch will work for power open or close cycles.
- If the vehicle theft alarm is armed, the overhead console switch will not open the liftgate; however, the FOBIK will.
- 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 system 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 full 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 system fuse. If the fuse is ineffective, the power liftgate system will not function.
- Some Diagnostic Trouble Codes (DTC) stored in the PLGM may cause the power liftgate system not to operate. Always use a diagnostic scan tool to check and clear DTCs from the PLGM before and after servicing any power liftgate system components.
POWER LIFTGATE INPUT - OUTPUT TABLE
POWER LIFTGATE SYSTEM INHIBIT MONITORS
The following is a list of inhibit monitors that may be observed using an appropriate diagnostic scan tool.
