Pinpoint Test F: Power Liftgate Does Not Power Close (Power Open OK)
Power Liftgate
Pinpoint Test F: The Power Liftgate Does Not Power Close (Power Open OK)
Normal Operation
When the power liftgate moves in the close direction, the Liftgate/Trunk Module (LTM) monitors the pinch strips and position sensor for obstacle detection. If the LTM (Liftgate/Trunk Module) detects a pinch strip is active or has a fault it aborts the power close. The LTM (Liftgate/Trunk Module) sends a voltage reference signal to both pinch strips. When a pinch strip is activated, it switches the voltage reference signal to ground. The right and left pinch strip return signal circuits are spliced together. When testing the pinch strips remember to test dynamically, check resistance with the pinch strip unactuated, actuated and then unactuated again.
The LTM (Liftgate/Trunk Module) also uses the switch inputs from the power liftgate latch to determine if there is an obstacle. When the LTM (Liftgate/Trunk Module) determines the liftgate is in secondary latch position it monitors the time it takes to close to primary latch position. If the liftgate does not close to the primary latch position within the specified amount of time, the LTM (Liftgate/Trunk Module) aborts the power close.
NOTE: Initialize the power liftgate before proceeding with this pinpoint test. Refer to Power Liftgate Initialization Programming and Relearning.
This pinpoint test is intended to diagnose the following:
- Initialization
- Mechanical binding
- Wiring, terminals or connectors
- Pinch strip
- Power liftgate latch
- LTM (Liftgate/Trunk Module)
PINPOINT TEST F : THE POWER LIFTGATE DOES NOT POWER CLOSE (POWER OPEN OK)
NOTICE: Use the correct probe adapter(s) from the Flex Probe Kit when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
F1 CHECK THE MANUAL OPERATION OF THE LIFTGATE
- While manually opening and closing the liftgate, check the liftgate for:
- liftgate/wedge alignment.
- strut operation (struts should push liftgate open when beyond half open).
- hinges (should move freely).
Does the liftgate open and close correctly?
Yes
GO to F2.
No
REPAIR as necessary. TEST the system for normal operation.
F2 CHECK THE LIFTGATE LEFT/RIGHT PINCH STRIP STATUS (LFT_PINCH / RT_PINCH) OPERATION
- Enter the following diagnostic mode on the scan tool: Liftgate/Trunk Module (LTM) DataLogger.
- Monitor the LTM (Liftgate/Trunk Module) PIDs LFT_PINCH and RT_PINCH while activating the left and right pinch strips.
Does the PID state change/agree with the pinch strip status?
Yes
GO to F11.
No
GO to F3.
F3 CHECK THE PINCH STRIP SIGNAL CIRCUIT
- Disconnect: Left Pinch Strip C4172 (for an inoperative left pinch strip).
- Disconnect: Right Pinch Strip C4173 (for an inoperative right pinch strip).
- Measure the voltage between left pinch strip C4172-1, circuit CPR52 (YE/VT), harness side and ground; or between right pinch strip C4173-1, circuit CPR51 (YE/OG), harness side and ground.
Is the voltage approximately 5 volts?
Yes
GO to F4.
No
If the voltage measured was greater than 5 volts, GO to F5.
If the voltage measured was less than 5 volts, GO to F6.
F4 CHECK THE SUSPECT PINCH STRIP RESISTANCE
- Measure the resistance between the suspect pinch strip, pins 1 and 2, component side, while releasing or firmly pressing the suspect pinch strip as indicated.
Is the pinch strip resistance between 5,700 ohms and 6,700 ohms with the pinch strip not pressed and between 0 to 200 ohms with the pinch strip firmly pressed and then between 5,700 ohms and 6,700 ohms with the pinch strip not pressed?
Yes
GO to F8.
No
INSTALL a pinch strip. REFER to Pinch Strip Switch Service and Repair. CLEAR DTCs. TEST the system for normal operation.
F5 CHECK THE PINCH STRIP SIGNAL CIRCUIT FOR SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: LTM (Liftgate/Trunk Module) C4174B.
- Ignition ON.
- Measure the voltage between left pinch strip C4172-1, circuit CPR52 (YE/VT), harness side and ground; or between right pinch strip C4173-1, circuit CPR51 (YE/OG), harness side and ground.
Is any voltage present?
Yes
REPAIR the circuit in question for a short to voltage. CLEAR the DTCs. REPEAT the LTM (Liftgate/Trunk Module) self-test.
No
GO to F16.
F6 CHECK THE PINCH STRIP SIGNAL CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: LTM (Liftgate/Trunk Module) C4174B.
- Measure the resistance between left pinch strip C4172-1, circuit CPR52 (YE/VT), harness side and ground; or between right pinch strip C4173-1, circuit CPR51 (YE/OG), harness side and ground.
Is the resistance greater than 10,000 ohms?
Yes
GO to F7.
No
REPAIR circuit in question for a short to ground. CLEAR the DTCs. REPEAT the LTM (Liftgate/Trunk Module) self-test.
F7 CHECK THE PINCH STRIP SIGNAL CIRCUIT FOR AN OPEN
- Measure the resistance between left pinch strip C4172-1, circuit CPR52 (YE/VT), harness side and LTM (Liftgate/Trunk Module) C4174B-25, circuit CPR52 (YE/VT), harness side.
- Measure the resistance between right pinch strip C4173-1, circuit CPR51 (YE/OG), harness side and LTM (Liftgate/Trunk Module) C4174B-1, circuit CPR51 (YE/OG), harness side.
Is the resistance less than 5 ohms?
Yes
GO to F16.
No
REPAIR the circuit in question for an open. CLEAR the DTCs. REPEAT the LTM (Liftgate/Trunk Module) self-test.
F8 CHECK THE PINCH STRIP RETURN CIRCUIT
- Ignition ON.
- Measure the voltage between the left pinch strip C4172-1, circuit CPR51 (YE/OG), harness side and the left pinch strip C4172-2, circuit RPR52 (VT/GY), harness side; or between the right pinch strip C4173-1, circuit CPR52 (YE/VT), harness side right pinch strip C4173-2, circuit RPR52 (VT/GY), harness side and ground.
Is the voltage approximately 5 volts?
Yes
INSTALL a new pinch strip for the pinch strip in question. REFER to Pinch Strip Switch Service and Repair. CLEAR the DTCs. REPEAT the LTM (Liftgate/Trunk Module) self-test.
No
GO to F9.
F9 CHECK THE PINCH STRIP SIGNAL CIRCUIT FOR SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: LTM (Liftgate/Trunk Module) C4174B.
- Ignition ON.
- Measure the voltage between left pinch strip C4172-2, circuit RPR52 (VT/GY), harness side and ground; or between right pinch strip C4173-2, circuit RPR52 (VT/GY), harness side and ground.
Is any voltage present?
Yes
REPAIR circuit RPR52 (VT/GY) for a short to voltage. CLEAR the DTCs. REPEAT the LTM (Liftgate/Trunk Module) self-test.
No
GO to F10.
F10 CHECK THE PINCH STRIP RETURN CIRCUIT FOR AN OPEN
- Measure the resistance between left pinch strip C4172-2, circuit RPR52 (VT/GY), harness side and LTM (Liftgate/Trunk Module) C4174B-8, circuit RPR52 (VT/GY), harness side; or between right pinch strip C4173-2, circuit RPR52 (VT/GY), harness side and LTM (Liftgate/Trunk Module) C4174B-8, circuit RPR52 (VT/GY), harness side.
Is the resistance less than 5 ohms?
Yes
GO to F16.
No
REPAIR the circuit for an open. CLEAR the DTCs. REPEAT the LTM (Liftgate/Trunk Module) self-test.
F11 CHECK THE DETENT AND FORKBOLT SWITCH PIDs
- Enter the following diagnostic mode on the scan tool: LTM (Liftgate/Trunk Module) DataLogger.
- Operate the liftgate manually while monitoring the following LTM (Liftgate/Trunk Module) PIDs:
- Detent Switch Status (DETENTSW)
- Forkbolt Switch Status (FORKBLT_S)
- Forkbolt Secondary Switch (FKSWSEC)
- NOTE: The liftgate is in the primary position when the liftgate is in the full closed position. The liftgate is in the unlatch position when the liftgate is open and completely out of the striker.
Begin with the liftgate in the open position, then slowly close the liftgate into each of the latch positions specified by the table below.
Liftgate Latch Position DETENTSW FORKBLT_S FKSWSEC Fully Unlatched Inactive aActive Active Primary Active Inactive Inactive
a If detent switch is active in the fully unlatched position, manually attempt to rotate the forkbolt towards the latched position.
Do the switch states agree with the table?
Yes
GO to F16.
No
GO to F12.
F12 CHECK THE OPERATION OF THE DETENT AND FORKBOLT SWITCHES
- Ignition OFF.
- Disconnect: LTM (Liftgate/Trunk Module) C4174B.
- Measure the resistance between LTM (Liftgate/Trunk Module) C4174B, harness side and ground at each of the connector pins and each latch position specified by the table below.
Liftgate Latch Position LTM (Liftgate/Trunk Module) Connector-Pin Circuit Resistance Fully Unlatched C4174B-3 CPR66 (GY/YE) Greater than 10,000 ohms aFully Unlatched C4174B-5 CPR64 (VT/OG) Less than 5 ohms Fully Unlatched C4174B-4 CPR65 (BU/GN) Less than 5 ohms Primary C4174B-3 CPR66 (GY/YE) Less than 5 ohms Primary C4174B-5 CPR64 (VT/OG) Greater than 10,000 ohms Primary C4174B-4 CPR65 (BU/GN) Greater than 10,000 ohms
a If resistance measured is less than 5 ohms, manually rotate the forkbolt to the latched position and retest.
Do the resistance values agree with the table?
Yes
GO to F16.
No
GO to F13.
F13 CHECK THE DETENT AND FORKBOLT SWITCH GROUND CIRCUIT
- Disconnect: Power Liftgate Latch C4339.
- Measure the resistance between power liftgate latch C4339-8, circuit GD149 (BK/GY), harness side and ground.
Is the resistance less than 5 ohms?
Yes
GO to F14.
No
REPAIR the circuit for an open. CLEAR the DTCs. REPEAT the LTM (Liftgate/Trunk Module) self-test.
F14 CHECK THE DETENT AND FORKBOLT SWITCH CIRCUITS FOR AN OPEN
- Measure the resistance between power liftgate latch C4339, harness side and LTM (Liftgate/Trunk Module) C4174B, harness side using the following table:
Power Liftgate Latch Connector-Pin Circuit LTM (Liftgate/Trunk Module) Connector-Pin C4339-2 CPR64 (VT/OG) C4174B-5 C4339-3 CPR65 (BU/GN) C4174B-4 C4339-5 CPR66 (GY/YE) C4174B-3
Is the resistance less than 5 ohms on all circuits?
Yes
GO to F15.
No
REPAIR the circuit in question for an open. CLEAR the DTCs. REPEAT the LTM (Liftgate/Trunk Module) self-test.
F15 CHECK THE DETENT AND FORKBOLT SWITCH CIRCUITS FOR A SHORT TO GROUND
- Measure the resistance between the LTM (Liftgate/Trunk Module) C4174B-5, circuit CPR64 (VT/OG), harness side and ground; then between the LTM (Liftgate/Trunk Module) C4174B-4, circuit CPR65 (BU/GN), harness side and ground; then between the LTM (Liftgate/Trunk Module) C4174B-3, circuit CPR66 (GY/YE), harness side and ground.
Is the resistance greater than 10,000 ohms on all circuits?
Yes
INSTALL a new power liftgate latch. CLEAR the DTCs. REPEAT the LTM (Liftgate/Trunk Module) self-test.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the LTM (Liftgate/Trunk Module) self-test.
F16 CHECK FOR CORRECT LTM (Liftgate/Trunk Module) OPERATION
- Disconnect all the LTM (Liftgate/Trunk Module) connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the LTM (Liftgate/Trunk Module) connectors and make sure they are seated correctly.
- Make sure the liftgate is fully closed.
- Operate the system and verify the concern is still present.
Is the concern still present?
Yes
INSTALL a new LTM (Liftgate/Trunk Module). REFER to Liftgate/Trunk Module (LTM) Service and Repair. TEST the system for normal operation.
No
The system is operating correctly at this time. Concern may have been caused by a loose or corroded connector.