B1975

B1975-POWER LIFTGATE LATCH CINCH - RATCHET SECONDARY SWITCH PERFORMANCE







Theory of Operation

The Secondary Ratchet Switch must remain closed when the liftgate is fully open or between full open and closed positions. The switch will open when the liftgate is fully closed and latched. This switch indicates when the latch is in secondary position. It is open when in secondary or primary and closed when out of secondary

- When Monitored:
Whenever the power liftgate latch is performing a cinching operation.

- Set Condition:
The ratchet secondary switch is unstable during a cinching operation.





1. DTC PRESENT

NOTE: Make sure the battery is fully charged and the vehicle charging system is operating properly before proceeding

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

1. With the scan tool, record and erase 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 B1975-POWER LIFTGATE LATCH CINCH - RATCHET SECONDARY 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. Check the liftgate seal to insure it is not to hard. Replace if necessary.
3. Manually operate the liftgate of a known good vehicle and notice the effort needed to open and close.
4. Compare the effort needed on the disabled liftgate.
5. 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
1. With the scan tool, monitor the SECONDARY RATCHET SWITCH CLOSED.
2. Using a screwdriver, click the latch to the first 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. CHECK THE (Q901) LOGIC GROUND CIRCUIT FOR AN OPEN




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

Is the resistance below 9.5 Ohms?

Yes

- Go To 5

No

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

5. CHECK THE (Q76) LATCH SECONDARY POSITION SENSE CIRCUIT FOR A SHORT TO GROUND




1. Measure the resistance between ground and the (Q76) Latch Secondary Position Sense circuit.
2. Wiggle the harness while observing the ohmmeter.

Is the resistance below 10,000 Ohms?

No

- Go To 6

Yes

- Repair the (Q76) Latch Secondary Position Sense circuit for a short to ground.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

6. CHECK THE (Q76) LATCH SECONDARY POSITION SENSE CIRCUIT FOR AN OPEN




1. Disconnect the Power Liftgate Module C2 harness connector.
2. Measure the resistance of the (Q76) Latch Secondary Position Sense between the Power Liftgate Module C2 harness connector and the Power Liftgate Latch harness connector.
3. Wiggle the harness while observing the ohmmeter.

Is the resistance below 2.0 Ohms?

No

- Repair the (Q76) Latch Secondary Position Sense circuit for an open.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

Yes

- Go To 7

7. (Q76) LATCH SECONDARY POSITION SENSE WIRE SHORT TO VOLTAGE




1. Turn the ignition on.
2. Measure the voltage of the (Q76) Latch Secondary Position Sense circuit.
3. Wiggle the harness while observing the voltmeter.

Is there any voltage present?

No

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

Yes

- Repair the (Q76) Latch Secondary Position Sense circuit for a short to voltage.
- Perform the BODY VERIFICATION TEST. Body Verification Test.