B1970

B1970-POWER LIFTGATE CLOSE DIRECTION - RATCHET PRIMARY SWITCH PERFORMANCE





For a complete wiring diagram, refer to the Wiring Information

- When Monitored:
Whenever the power liftgate in performing a power close operation.

- Set Condition:
The ratchet primary switch is detected as open when the liftgate power drive unit position count is greater than 90.





1. DIAGNOSTIC TROUBLE CODE (DTC) PRESENT

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

1. Using 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. Using the scan tool, read ACTIVE DIAGNOSTIC TROUBLE CODE (DTC)s.

Does the scan tool display B1970-POWER LIFTGATE CLOSE DIRECTION - 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

- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Go To 3

3. POWER LIFTGATE MODULE
1. Using 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?

Yes

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

No

- Go To 4

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) Logic 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) Logic Ground circuit for an open.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

5. (G78) LIFTGATE AJAR SWITCH SENSE CIRCUIT OPEN




1. Disconnect the Power Liftgate Module C2 harness connector.
2. Measure the resistance of the (G78) Liftgate Ajar Switch Sense circuit between the Power Liftgate C2 connector and the Power Liftgate Latch 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 circuit for an open.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

6. CHECK THE (G78) LIFTGATE AJAR SWITCH SENSE CIRCUIT FOR A SHORT TO THE (Q901) LOGIC GROUND CIRCUIT




1. Reconnect the Power Liftgate Module C2 harness connector.
2. Measure the resistance between the (G78) Liftgate Ajar Switch Sense circuit and the (Q901) Logic Ground circuit.
3. Wiggle the harness while observing the ohmmeter.

Is the resistance below 1000.0 Ohms?

Yes

- Repair the (G78) Liftgate Ajar Switch Sense circuit for a short to ground. If there are no problems with the (G78) Liftgate Ajar Sense circuit and the (Q901) Logic Ground circuit between the Power Liftgate Drive Unit harness connector and the Power Liftgate Module C2 harness connector, replace the Power Liftgate Module.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

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

7. (G78) LIFTGATE AJAR SWITCH SENSE CIRCUIT SHORTED TO GROUND




1. Reconnect the Power Liftgate Module harness connectors.
2. Measure the resistance between ground and the (G78) Liftgate Ajar Switch Sense circuit.
3. Wiggle the harness while observing the ohmmeter.

Is the resistance below 1000.0 Ohms?

Yes

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

No

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