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Home >> Mercury >> 2009 >> Sable FWD V6-3.5L >> Repair and Diagnosis >> Body and Frame >> Doors, Hood and Trunk >> Trunk / Liftgate >> Testing and Inspection >> Pinpoint Tests >> Pinpoint Test D: The Power Liftgate Does Not Operate Correctly - Reverses During The Power Close Operation

Pinpoint Test D: The Power Liftgate Does Not Operate Correctly - Reverses During The Power Close Operation




Power Liftgate

Pinpoint Tests

Pinpoint Test D: The Power Liftgate Does Not Operate Correctly - Reverses During the Power Close Operation

Refer to Wiring Diagram Set 109, Power Liftgate/Retractable Running Board for schematic and connector information. Diagrams By Number

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. The LTM uses a 5-volt reference signal on circuit CPR52 (YE/VT) and a return signal on circuit RPR52 (VT/GY) for the left pinch strip. The LTM uses a 5-volt reference signal on circuit CPR51 (YE/OG) and a return signal on circuit RPR52 (VT/GY) for the right pinch strip. The right and left pinch strip return signal circuits are spliced together.

The position sensor receives 5 volts from the LTM through circuit CPR55 (GN/BU) and ground from the LTM through circuit RPR55 (WH/BU). The position sensor output signal is supplied to the LTM through circuit VPR53 (BU/WH) and VPR54 (BU/BN).

- DTC B107D Obstacle Detected While Closing - The LTM will set this DTC if an obstacle is detected during powered open/close during self-test only.
- DTC B2419 Sensor 1 Invalid - This DTC sets when the LTM detects the position sensor feedback signals are not correct.
- DTC B2420 Sensor 2 Invalid - This DTC sets when the LTM detects the position sensor feedback signals are not correct.

This pinpoint test is intended to diagnose the following:
- Mechanical binding
- Power liftgate latch striker alignment
- Power liftgate latch
- Power liftgate motor
- LTM
- Wedges
- Wiring, terminals or connectors



PINPOINT TEST D: THE POWER LIFTGATE DOES NOT OPERATE CORRECTLY - REVERSES DURING THE POWER CLOSE OPERATION

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D1 CHECK THE MANUAL OPERATION OF THE LIFTGATE


- Turn the power liftgate OFF (disable) from the message center.
- While manually opening and closing the liftgate, check the liftgate for:
- liftgate/wedge alignment.
- strut operation (struts should push open liftgate when beyond half open).
- power liftgate rod (should move freely while manually opening and closing liftgate and should be securely mounted to the liftgate and bracket).
- power liftgate latch (should latch completely).
- Does the liftgate open and close correctly?

Yes
If the liftgate reverses near the midpoint of travel, GO to D2.

If the liftgate reverses near or at the latch, GO to D10.

No
REPAIR as necessary. ALIGN as necessary. REFER to Liftgate Alignment Adjustments. CLEAR the DTCs. REPEAT the LTM self-test.

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D2 CHECK THE POSITION SENSOR PID


- Ignition OFF.
- Connect: All LTM Connectors.
- Connect: Power Liftgate Motor C4332.
- Ignition ON.
- Open the liftgate to the full open position.
- Enter the following diagnostic mode on the scan tool: DataLogger - LTM.
- Monitor the LTM PIDs OPT_SEN_1 and OPT_SEN_2 while slowly closing the liftgate.
- Do both of the PID values alternate from ACTIVE to INACTIVE while the liftgate is moving?

Yes
GO to D11.

No
GO to D3.

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D3 CHECK THE POSITION SENSOR POWER CIRCUIT


- Disconnect: Power Liftgate Motor C4332.
- Ignition ON.
- Measure the voltage between power liftgate motor C4332-4, circuit CPR55 (GN/BU), harness side and ground.




- Is the voltage approximately 5 volts?

Yes
GO to D5.

No
GO to D4.

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D4 CHECK THE POSITION SENSOR POWER CIRCUIT FOR AN OPEN OR SHORT TO GROUND


- Ignition OFF.
- Disconnect: LTM C4174A.
- Measure the resistance between LTM C4174A-6, circuit CPR55 (GN/BU), harness side and power liftgate motor C4332-4, circuit CPR55 (GN/BU), harness side; and between LTM C4174A-6, circuit CPR55 (GN/BU), harness side and ground.




- Is the resistance less than 5 ohms between LTM and power liftgate motor; and greater than 10,000 ohms between LTM and ground?

Yes
GO to D16.

No
REPAIR the circuit. CLEAR the DTCs. REPEAT the LTM self-test.

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D5 CHECK THE POSITION SENSOR RETURN CIRCUIT


- Ignition OFF.
- Disconnect: Power Liftgate Motor C4332.
- Ignition ON.
- Measure the resistance between power liftgate motor C4332-9, circuit RPR55 (WH/BU), harness side and ground.




- Is the resistance less than 50 ohms?

Yes
GO to D7.

No
GO to D6.

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D6 CHECK THE POSITION SENSOR RETURN CIRCUIT FOR AN OPEN


- Ignition OFF.
- Disconnect: LTM C4174A.
- Measure the resistance between LTM C4174A-7, circuit RPR55 (WH/BU), harness side and power liftgate motor C4332-9, circuit RPR55 (WH/BU), harness side.




- Is the resistance less than 5 ohms?

Yes
GO to D16.

No
REPAIR the circuit. CLEAR the DTCs. REPEAT the LTM self-test.

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D7 CHECK THE POSITION SENSOR CIRCUITS FOR AN OPEN


- Ignition ON.
- Measure the voltage between power liftgate motor C4332-8, circuit VPR54 (BU/BN), harness side and ground; and between power liftgate motor C4332-3, circuit VPR53 (BU/WH), harness side and ground.




- Is the voltage approximately 5 volts for both measurements?

Yes
INSTALL a new power liftgate motor. REFER to Power Liftgate Motor Service and Repair. CLEAR the DTCs. REPEAT the LTM self-test.

No
GO to D8.

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D8 CHECK THE POSITION SENSOR CIRCUITS FOR AN OPEN


- Ignition OFF.
- Disconnect: LTM C4174A.
- Measure the resistance between power liftgate motor C4332, harness side and LTM C4174A, harness side using the following chart:









- Are the resistances less than 5 ohms?

Yes
GO to D9.

No
REPAIR the circuit. CLEAR the DTCs. REPEAT the LTM self-test.

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D9 CHECK THE POSITION SENSOR CIRCUITS FOR A SHORT TO GROUND


- Measure the resistance between power liftgate motor C4332-3, circuit VPR53 (BU/WH), harness side and ground; and between power liftgate motor C4332-8, circuit VPR54 (BU/BN), harness side and ground.




- Are the resistances greater than 10,000 ohms?

Yes
GO to D10.

No
REPAIR the circuit. CLEAR the DTCs. REPEAT the LTM self-test.

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D10 CHECK THE POSITION SENSOR CIRCUITS FOR A SHORT TO VOLTAGE


- Ignition ON.
- Measure the voltage between power liftgate motor C4332-3, circuit VPR53 (BU/WH), harness side and ground; and between power liftgate motor C4332-8, circuit VPR54 (BU/BN), harness side and ground.




- Is any voltage present?

Yes
REPAIR the circuit. CLEAR the DTCs. REPEAT the LTM self-test.

No
GO to D16.

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D11 CHECK THE DETENT AND FORKBOLT SWITCH PID


- Enter the following diagnostic mode on the scan tool: DataLogger - LTM.
- Operate the liftgate manually while monitoring the following LTM 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. The liftgate can be placed in the unlatched position by lifting up on the liftgate handle.
- Begin with the liftgate in the open position, then slowly close the liftgate into each of the latch positions specified by the table below.





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 D16.

No
GO to D12.

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D12 CHECK THE OPERATION OF THE DETENT AND FORKBOLT SWITCHES


- Ignition OFF.
- Disconnect: LTM C4174A.
- Measure the resistance between LTM C4174A, harness side and ground at each of the connector pins and each latch position specified by the chart below.





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 chart?

Yes
GO to D16.

No
GO to D13.

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D13 CHECK THE DETENT AND FORKBOLT SWITCH GROUND CIRCUIT


- Disconnect: Liftgate Latch/Unlatch Assembly C4339.
- Measure the resistance between power liftgate latch/unlatch assembly C4339-8, circuit GD147 (BK/VT), harness side and ground.




- Is the resistance less than 5 ohms?

Yes
GO to D14.

No
REPAIR the circuit. CLEAR the DTCs. REPEAT the LTM self-test.

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D14 CHECK THE DETENT AND FORKBOLT SWITCH CIRCUITS FOR AN OPEN


- Measure the resistance between power liftgate latch/unlatch assembly C4339, harness side and LTM C4174A, harness side using the following chart:









- Is the resistance less than 5 ohms on all circuits?

Yes
GO to D15.

No
REPAIR the circuit. CLEAR the DTCs. REPEAT the LTM self-test.

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D15 CHECK THE DETENT AND FORKBOLT SWITCH CIRCUITS FOR A SHORT TO GROUND


- Measure the resistance between LTM C4174A-4, circuit CPR64 (VT/OG), harness side and ground; between LTM C4174A-5, circuit CPR65 (BU/GN), harness side and ground; then between LTM C4174A-3, circuit CPR66 (GY/YE), harness side and ground.




- Are the resistances greater than 10,000 ohms on all circuits?

Yes
CHECK the power liftgate latch connector for bent or corroded connections on the component side and harness side. REPAIR as necessary.

INSTALL a new power liftgate latch. CLEAR the DTCs. REPEAT the LTM self-test.

No
REPAIR the circuit. CLEAR the DTCs. REPEAT the LTM self-test.

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D16 CHECK FOR CORRECT LTM OPERATION


- Disconnect all the LTM connectors.
- Check for:
- corrosion.
- pushed-out pins.
- Connect all the LTM 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. REFER to Liftgate/Trunk Module (LTM) Service and Repair. REPEAT the LTM self-test.

No
The system is operating correctly at this time. Concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the LTM self-test.

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