Component Tests and General Diagnostics

Diagnosis And Testing - Power Tailgate System

Check the following items prior to performing Power Tailgate System (PTG) service.
1. Manual Movement
Make sure the tailgate moves manually. Place the ON/OFF Switch located in the glove box area in the OFF position. Move the gate manually and check for proper gate fit and latch effort. Check for interference with other body parts such as latch striker, gate guide bumpers, and weather seals. Correct these problems first. The PTG system works best when the manual operation is smooth and correct.
2. Battery Voltage
Make sure the battery is fully charged. The PTG system is an electronic device and requires a minimum battery voltage to operate. The PTG Control Module (PTGM) monitors the battery voltage present at the PTGM battery input terminal and will not permit operation if the battery voltage is out of range.
3. Fuses
Check to make sure that the fuses are intact.
Two fuses protect the battery supply to the PTGM, one for Power, and one for Logic Signals.
Power Fuse (30A) is located in the Main Fuse Block in the Engine Room and the Memory Fuse (15A, Shunt Switch) for the logic signal line is located in the fuse box under the steering column.
4. System Response
Spend some time to observe how the system responds to each different input signal upon change in the Central Lock/Unlock status as well as the ON/OFF Switch status. The system may react differently to a certain input such as the RKE or the Master Open/Close Switch than the other inputs such as the Local Open/Close Switch and the Outside Handle Switch.
Check also to see if there is only partial trouble with the system such as only power closing is in trouble while power opening function works fine. This kind of observation will help you narrow down the possible root-causes.
5. Vehicle on Steep Grade or Uneven Surface
Make sure the customer has not been operating the PTG system when the vehicle is parked on a steep grade (greater than 20%) or an uneven surface such as with one or more wheels on a curb or in a hole or when the vehicle is raised on a jack. The system may or may not properly operate in those extreme conditions. Also the force of gravity and normal flex of the vehicle body might have damaged the system interface if power operation has ever been tried in such unstable conditions.
6. Obstacle Detection
The obstacle detection force is not adjustable. Factors that may affect the force are vehicle grade, battery voltage, or vertical location of the tailgate. Soft obstacle will increase the effort to reverse the gate.
To check the obstacle detection force, simply stand against the tailgate and push it while it is power closing. Obstacle detection force in power opening is usually higher than in closing.
7. Build Variation
The tailgates are not identical. Open and close times and obstacle detection efforts may vary when comparing the vehicles. This is normal and is caused by vehicle build conditions such as body-gate fit, gate hinge balance, and seal force.
8. Hi-Scan Diagnostic Tools
Connect the Hi-Scan tool to the K-line OBD connectors and check the status of the system.
Diagnostic Trouble Codes and the Service Data will be useful to diagnose the trouble.
9. Hi-Scan Tool Software Program (ROM PACK) Update
There may be a new update release of the scanner software program that complies with the change of the system or vehicle interface available for you.

NOTE:
The Power Tailgate Control Module (PTGM) controls the Drive Unit Motor, Clutch, and the Power Latch Actuators. The PTGM responds to commands from the external switches such as the Master Open/Close, Local Open/Close, RKE, or from the Outside Handle Switch. It cannot initiate a power open operation without a request from one of the inputs and then only if the vehicle conditions are correct, e.g.: vehicle not moving, unlocked, battery voltage within range, etc.

Chime shall operate when a power operation cannot be performed as requested (a one time chime sound). Chime shall operate as well but three consecutive times when an obstacle has been detected or the system could not finish power operation as expected.
There is no chime indication related with DTC set.













Tailgate Adjustment
The tailgate must move freely and smoothly in order for the Power Tailgate system to function properly. The PTG system can adjust for some minor changes in the effort required to move the tailgate. However, in extreme conditions, the tailgate may need to be mechanically adjusted for proper fit and finish.
If a problem exists with the Power Tailgate and it is suspected to be extreme effort, check the tailgate gas struts and hinges for free movement. Use a known good vehicle for tailgate effort comparison. The gas strut efforts change with temperature and may be very stiff when the temperature is hot and very light when cold.

PTG Learn Cycle (System Initialization)
A learn cycle must be performed whenever the electrical power to the PTGM has been removed. The learn cycle enables the PTGM to learn the range of full travel and effort required to power the Tailgate which allows it to perform properly and safely.

PTG Drive Unit
Vehicles equipped with a Power Tailgate system, use a power tailgate drive unit that consists of a DC motor assembly, optical sensor assembly, clutch assembly, PTGM, push rod, rack, housing/bracket assembly and wire harness. The clutch and motor portion of the assembly provides the power and torque required to open or close the tailgate. The optical sensor provides the motor speed signal to the PTGM.

Replaceable components of the power tailgate drive unit assembly are the Drive Unit Assembly, Push Rod, Rod Clip, Power Latch, and PTGM. The drive unit and the components cannot be adjusted or repaired, and if damaged, must be replaced.

Tailgate Motor
- Open tailgate and remove D-pillar trim to access the power tailgate motor.
- Connect a 12 Volt D.C power source to motor wires. If the motor rotates in either direction when the polarity is reversed, the motor is functional.
Optical Sensor
The PTG drive unit uses an optical sensor that is located on the drive unit clutch housing and sends motor speed signals to the ECU. This speed signal is used by the PTGM to control the motor and to detect obstacles in the Power Tailgate path.
The optical sensor cannot be adjusted or repaired, and if found to be faulty, must be replaced.

PTGM (Power Tailgate Control Module, ECU)
Attached to the drive unit, the Power Tailgate system includes a microprocessor based controller called PTGM to operate and control the drive mechanism and to communicate with the vehicle interface. The PTGM receives various signals from the vehicle and also sends out signals either to communicate with vehicle interface or to operate devices like chime. The PTGM can detect certain faults and will set DTC (Diagnostic Trouble Codes) that can be read through the K-line ISO 9141 diagnostic bus using the Hi-Scan tool.
The PTGM cannot be adjusted or repaired, and if found to be faulty, must be replaced.

Push Rod
Vehicles equipped with a Power Tailgate use a push rod assembly. This push rod is located in the left rear of the vehicle and is visible without removing the D-pillar trim. The push rod attaches the power tailgate drive unit assembly to the tailgate.
The push rod consists of a steel shaft, equipped with spherical rod end receptacles at each end. The weight of the tailgate is not supported by the push rod; the tailgate gas struts are designed to support the tailgate.
The push rod cannot be adjusted or repaired, and if damaged, must be replaced.

Latch and Lock Mechanism




Vehicles equipped with a Power Tailgate, use a Power Latch. This latch performs the same function as a manual tailgate latch and also provides power cinch and power release (unlatch). The Power Latch is located in the lower center of the tailgate and contains three integral switches. These switches provide latch status information to the PTGM. The Power Latch cannot be adjusted or repaired and must be replaced if found defective.

NOTE:
In case either of the anti-pinch sensors is faulty, "Power Cinching" from the latch as well as the power opening and closing will become disabled and only "Power Unlatching" though the outside handle switch will be functional at this time for maximized safety.

If Power Latch will not open electrically due to outside handle switch failure, loss of electrical power to the latch, power unlatch motor malfunction, etc., then the Power Latch can be manually unlatched by removing the trim plug and pulling the Service Release Lever on the latch.

Anti-Pinch Sensors
Vehicles equipped with a Power Tailgate use two pinch sensors, one on each side of the Tailgate. The sensors look like weather-strips, however they consist of pieces of electrically conductive rubber (tape switch), wires, resistor, double sided tape, and a plastic carrier. Pinch sensors are used to provide additional protection against personal injury or vehicle damage caused by an obstacle being "pinched" between the tailgate and the tailgate opening of the vehicle.

Operation
If either of the pinch sensors detects an obstruction or "Pinched" condition during a power close cycle, the PTGM will immediately stop the power closing operation and reverse the direction of the drive motor to power open the tailgate to the full open position.

Diagnosis and Testing - Anti-Pinch Sensors
To verify Power Tailgate system and pinch sensor operation,
- Cycle the Power Tailgate through two complete open and close cycles, during each of the final close cycles, with the tailgate in mid-travel, depress each of the pinch sensors to verify that the PTGM detects an obstruction. If it works (tailgate reverses), the pinch sensors and the module are okay.
- If it does not work, check to see if a pinch sensor error diagnostic trouble code is set using a Hi-scan tool. The next step will be to replace the inoperable pinch sensor assembly. Checking for continuity on the two wires leading from the pinch sensor using an ohmmeter can be an alternative way of diagnosing the trouble prior to replacement.
Input/Output Monitoring