Diagnostic Test
- CHECK FOR AN ACTIVE DTC NOTE:
This DTC will only set during the power open operation after the four second time out. This may make it difficult to reproduce.
- Turn the ignition on.
- With the scan tool, create a Vehicle Scan Report and attach it to the repair order.
- Erase DTCs.
- Turn the ignition off, wait 10 seconds, then turn the ignition on.
- Operate the power liftgate several times if possible.
- With the scan tool, read the PLGM DTCs.
Is the DTC active?
Yes
- Go To 2
No
- Perform the TESTING FOR AN INTERMITTENT CONDITION procedure. Refer to TESTING FOR AN INTERMITTENT CONDITION .
- CHECK FOR A BINDING LIFTGATE
- 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.
- Manually operate the liftgate of a known good vehicle and notice the effort needed to open and close.
- Compare the effort needed on the disabled liftgate.
- 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 the Service information for the related symptom(s). Refer to STANDARD PROCEDURE .
- Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
No
- Go To 3
- CHECK THE LATCH HOME POSITION
- CHECK THE POWER LIFTGATE LATCH
- Disconnect the Power Liftgate Latch harness connector.
- With the scan tool, monitor the Sector Gear Switch Closed state.
- Connect a jumper wire between the (Q79) Sector Switch Sense circuit and the (Q901) Sensor Ground circuit.
- Repeat the previous step several times by disconnecting and connecting the jumper while observing the scan tool.
Did the scan tool show the switch state changing correctly every time the jumper was connected and disconnected?
Yes
- Replace the Power Liftgate Latch in accordance with the service information and using the scan tool, run the "Latch Home Sector Test". Refer to LATCH, REMOVAL AND INSTALLATION .
- Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
No
- Go To 5
- CHECK THE (Q901) LOGIC GROUND CIRCUIT FOR AN OPEN OR HIGH RESISTANCE
- Turn the ignition off.
- Cycle all lights off.
- Check for continuity between ground and the (Q901) Logic Ground circuit at the Power Liftgate Latch harness connector.
- Wiggle the harness while observing the ohmmeter.
Is there continuity between ground and the (Q901) Logic Ground circuit?
Yes
- Go To 6
No
- Repair the (Q901) Logic Ground circuit for an open or high resistance.
- Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
- CHECK THE (Q79) SECTOR SWITCH SENSE CIRCUIT FOR A SHORT TO GROUND
- Check for continuity between the (Q901) Logic Ground circuit and the (Q79) Sector Switch Sense circuit at the Power Liftgate Latch harness connector.
- Wiggle the harness while observing the ohmmeter.
Is there continuity between the (Q901) Logic Ground circuit and the (Q79) Sector Switch Sense circuit?
Yes
- Go To 11
No
- Go To 7
- CHECK THE (Q79) SECTOR SWITCH SENSE CIRCUIT FOR AN OPEN OR HIGH RESISTANCE
- Disconnect the PLGM C2 harness connector.
- Measure the resistance of the (Q79) Sector Switch Sense circuit between the Power Liftgate C2 harness connector and the Power Liftgate Latch harness connector.
- Wiggle the harness while observing the ohmmeter.
Is the resistance below 2.0 Ohms?
Yes
- Go To 8
No
- Repair the (Q79) Sector Switch Sense circuit for an open or high resistance.
- Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
- CHECK THE (Q79) SECTOR SWITCH SENSE CIRCUIT FOR A SHORT TO VOLTAGE
- Turn the ignition on.
- Measure the voltage of the (Q79) Sector Switch Sense circuit.
- Wiggle the harness while observing the voltmeter.
Is there any voltage present?
No
- Go To 12
Yes
- Repair the (Q79) Sector Switch Sense circuit for a short to voltage.
- Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
- ADJUST LATCH TO HOME POSITION
- Close the liftgate.
- With the scan tool run the "Latch Home Sector Test".NOTE:
This test will try to adjust the sector gear to the Home Position.
- With the scan tool in Inputs/Outputs, read the "Sector Gear Switch Closed" state.
Does the scan tool display: NO?
Yes
- Repair is complete. The latch was not in the Home position.
- Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
No
- Go To 10
- CHECK THE (Q79) SECTOR SWITCH SENSE CIRCUIT FOR A SHORT TO THE (Q901) LOGIC GROUND CIRCUIT
- Disconnect the Power Liftgate Latch harness connector.
- Check for continuity between the (Q901) Logic Ground circuit and the (Q79) Sector Switch Sense circuit at the Power Liftgate Latch harness connector.
- Wiggle the harness while observing the ohmmeter.
Is there continuity between the (Q901) Logic Ground circuit and the (Q79) Sector Switch Sense circuit?
Yes
- Go To 11
No
- Replace the Power Liftgate Latch assembly in accordance with the Service Information and using the scan tool, run the "Latch Home Sector Test". Refer to LATCH, REMOVAL AND INSTALLATION .
- Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
- CHECK THE (Q79) SECTOR SWITCH SENSE CIRCUIT FOR A SHORT TO GROUND
- Disconnect the PLGM C2 harness connector.
- Check for continuity between ground and the (Q79) Sector Switch Sense circuit at the Power Liftgate Latch harness connector.
- Wiggle the harness while observing the ohmmeter.
Is there continuity between ground and the (Q79) Sector Switch Sense circuit?
Yes
- Repair the (Q79) Sector Switch Sense circuit for a short to ground.
- Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
No
- Go To 12
- CHECK RELATED HARNESS CONNECTIONS
- Disconnect all PLGM harness connectors.
- Disconnect all related in-line harness connections (if equipped).
- Disconnect the related component harness connectors.
- Inspect harness connectors, component connectors, and all male and female terminals for the following conditions:
- Proper connector installation.
- Damaged connector locks.
- Corrosion.
- Other signs of water intrusion.
- Weather seal damage (if equipped).
- Bent terminals.
- Overheating due to a poor connection (terminal may be discolored due to excessive current draw).
- Terminals that have been pushed back into the connector cavity.
- Perform a terminal drag test on each connector terminal to verify proper terminal tension.
Repair any conditions that are found.
- Reconnect all PLGM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
- Reconnect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
- Reconnect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
- With the scan tool, erase DTCs.
- Using the recorded Vehicle Scan Report, along with the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
- With the scan tool, read PLGM DTCs.
Did the DTC return?
Yes
- Replace the Power Liftgate Module (PLGM) in accordance with the Service Information. Refer to MODULE, POWER LIFTGATE (PLGM), REMOVAL AND INSTALLATION .
- Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
No
- Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
- Test complete.