B1977–POWER LIFTGATE OPEN DIRECTION – SECTOR SWITCH PERFORMANCE

For a complete wiring diagram Refer to Section 8W

When Monitored:
Prior to the power liftgate performing a power open operation.
Set Condition:
The sector switch is closed when it should be open during a power open.

Possible Causes

BINDING LIFTGATE

LATCH NOT IN HOME POSITION

(Q79) SECTOR SWITCH SENSE CIRCUIT SHORT TO GROUND

(Q79) SECTOR SWITCH SENSE CIRCUIT SHORT TO THE (Q901) LOGIC GROUND CIRCUIT

POWER LIFTGATE LATCH

POWER LIFTGATE MODULE

Diagnostic Test

1.CHECK FOR DTCS

NOTE: This DTC will only set during the power open operation after the four second time out. This may make it difficult to reproduce.

Does the scan tool display B1977–POWER LIFTGATE OPEN OPERATION - SECTOR SWITCH PERFORMANCE?

Yes

Go To2

Using the wiring diagram/schematic as a guide, inspect the wiring and connectors for an intermittent condition. Operate the door several times and check for any binding or other obstructions.
Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).

2.BINDING LIFTGATE

Does it take more effort to operate the liftgate than it should?

Yes

Refer to Service information for the related symptom(s).
Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).

Go To 3

3.LATCH HOME POSITION

Does the scan tool display TRUE?

Yes

Go To 6

Go To 4

4.POWER LIFTGATE LATCH

Did the scan tool show the switch state changing correctly every time the jumper was connected and disconnected?

No

Go To5

Yes

Replace the Power Liftgate Latch in accordance with the service information.
Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE)

5.CHECK THE (Q79) SECTOR SWITCH SENSE CIRCUIT FOR A SHORT TO GROUND

Is the resistance below 100.0 ohms?

No

Go To 6

Yes

Repair the (Q79) Sector Switch Sense circuit for a short to the (Q901) Logic Ground circuit.
Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).

6.ADJUST LATCH TO HOME POSITION

NOTE: This test will try to adjust the sector gear to the Home Position.

Does the scan tool display: FALSE?

No

Go To 7

Yes

Repair is complete. The latch was not in the Home position.
Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).

7.CHECK THE (Q79) SECTOR SWITCH SENSE CIRCUIT FOR A SHORT TO THE (Q901) LOGIC GROUND CIRCUIT

Is the resistance below 1000.0 ohms?

No

Replace the Power Liftgate Latch assembly and with the scan tool run the “Latch Home Position Test”.
Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).

Yes

Go To 8.

8.CHECK THE (Q79) SECTOR SWITCH SENSE CIRCUIT FOR A SHORT TO GROUND

Is the resistance below 1000.0 ohms?

No

Replace the Power Liftgate Module in accordance with the service information.
Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).

Yes

Repair the (Q79) Sector Switch Sense circuit for a short to ground.
Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).