B1972

B1972-POWER LIFTGATE LATCH RELEASE - RATCHET PRIMARY SWITCH PERFORMANCE





For a complete wiring diagram, refer to the Wiring Information Electrical Diagrams.

- When Monitored:
Whenever the power liftgate is being manually moved, is at the full open position, or has just completed a power open cycle.

- Set Condition:
The pawl switch was detected as grounded but the ratchet switch remained open.





1. DTC PRESENT

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

1. With the scan tool, record and erase the DTCs.
2. Turn the ignition off, wait 10 seconds, then turn the ignition on.
3. Operate the power liftgate several times if possible.
4. With the scan tool, read ACTIVE DTCs.

Does the scan tool display B1972-POWER LIFTGATE LATCH RELEASE - RATCHET PRIMARY SWITCH PERFORMANCE?

Yes

- Go To 2

No

- 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 the BODY VERIFICATION TEST. Body Verification Test.

2. BINDING LIFTGATE
1. Examine the liftgate for proper fit and alignment, loose/hard or torn seals, misaligned latch striker or anything that would cause an obstruction to proper operation.
2. Manually operate the liftgate of a known good vehicle and notice the effort needed to open and close.
3. Compare the effort needed on the disabled liftgate.
4. Especially notice the effort needed to unlatch and close the liftgate.

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

Yes

- Refer to Service information for the related symptom(s).
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Go To 3

3. POWER LIFTGATE MODULE (PLGM)
1. With the scan tool, monitor the PRIMARY RATCHET SWITCH.
2. Using a screwdriver, click the latch to the second detent while observing the scan tool.
3. Unlatch the latch by pressing the handle switch and observe the scan tool for a change of state.
4. Repeat this step several times while moving the liftgate in different positions and wiggling the harness to check for an intermittent open or shorted circuit.

Did the scan tool show the switch state changing correctly every time?

No

- Go To 4

Yes

- Replace the Power Liftgate Module.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

4. (Q901) LOGIC GROUND WIRE OPEN




1. Turn the ignition off.
2. Turn all lights off.
3. Disconnect the Power Liftgate Latch harness connector.
4. Measure the resistance between ground and the (Q901) Logic Ground circuit in the Liftgate Latch harness connector.
5. Wiggle the harness while observing the ohmmeter.

Is the resistance below 9.5 Ohms?

Yes

- Go To 5

No

- Repair the (Q901) Logic Ground wire for an open.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

5. (G78) LIFTGATE AJAR SWITCH SENSE WIRE OPEN




1. Disconnect the Power Liftgate Module C2 harness connector.
2. Measure the resistance of the (G78) Liftgate Ajar Switch Sense wire between the PLG Module C2 harness connector and the Liftgate Latch harness connector.
3. Wiggle the harness while observing the ohmmeter.

Is the resistance below 2.0 Ohms?

Yes
Go To 6
No

- Repair the (G78) Liftgate Ajar Switch Sense wire for an open.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

6. CHECK THE (G78) LIFTGATE AJAR SWITCH SENSE CIRCUIT FOR A SHORT TO VOLTAGE




1. Turn the ignition on.
2. Measure the voltage between ground and the (G78) Liftgate Ajar Switch Sense circuit.
3. Wiggle the harness while observing the voltmeter.

Is there any voltage present?

Yes

- Repair the (G78) Liftgate Ajar Switch Sense circuit for a short to voltage.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Replace the Liftgate Cinch/Release Motor Assembly.
- Perform the BODY VERIFICATION TEST. Body Verification Test.