Diagnostic Test

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.
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 B1977-POWER LIFTGATE OPEN OPERATION - SECTOR SWITCH PERFORMANCE?
  
  Yes
  - Go to step 2
  No
  - Using the SYSTEM WIRING DIAGRAMS 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. Refer to DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
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. Refer to DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
  No
  - Go to step 3
LATCH HOME POSITION
1. Make sure the liftgate is closed.
2. With the scan tool in Inputs/Outputs, read the "Sector Gear Switch Closed" state.
  Does the scan tool display TRUE?
  
  Yes
  - Go to step 6
  No
  - Go to step 4
POWER LIFTGATE LATCH

Fig 1: Checking Power Liftgate Latch
Courtesy of CHRYSLER LLC
1. Disconnect the Power Liftgate Latch harness connector.
2. Using the scan tool, monitor the Sector Gear Switch Closed.
3. Connect a jumper wire between the (Q79) Sector Switch Sense circuit and the (Q901) Sensor Ground circuit.
4. 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.
  - Perform the BODY VERIFICATION TEST. Refer to DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
  No
  - Go to step 5
CHECK THE (Q79) SECTOR SWITCH SENSE CIRCUIT FOR A SHORT TO GROUND

Fig 2: Checking Sector Switch Sense Circuit For A Short To Ground
Courtesy of CHRYSLER LLC
1. Measure the resistance between the (Q901) Logic Ground circuit and the (Q79) Sector Switch Sense circuit.
2. Wiggle the harness while observing the ohmmeter.
  Is the resistance below 100.0 Ohms?
  
  Yes
  - Repair the (Q79) Sector Switch Sense circuit for a short to the (Q901) Logic Ground circuit.
  - Perform the BODY VERIFICATION TEST. Refer to DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
  No
  - Go to step 6
ADJUST LATCH TO HOME POSITION
1. Close the liftgate.
2. With the scan tool run the "Latch Home Position Test".
  NOTE: This test will try to adjust the sector gear to the Home Position.
3. With the scan tool in Inputs/Outputs, read the "Sector Gear Switch Closed" state.
  Does the scan tool display: FALSE?
  
  Yes
  - Repair is complete. The latch was not in the Home position.
  - Perform the BODY VERIFICATION TEST. Refer to DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
  No
  - Go to step 7
CHECK THE (Q79) SECTOR SWITCH SENSE CIRCUIT FOR A SHORT TO THE (Q901) LOGIC GROUND CIRCUIT

Fig 3: Checking Sector Switch Sense Circuit For A Short To Ground
Courtesy of CHRYSLER LLC
1. Disconnect the Power Liftgate Latch harness connector.
2. Measure the resistance between the (Q901) Logic Ground circuit and the (Q79) Sector Switch Sense circuit.
3. Wiggle the harness while observing the ohmmeter.
  Is the resistance below 1000.0 Ohms?
  
  Yes
  - Go to step 8
  No
  - Replace the Power Liftgate Latch assembly and with the scan tool run the "Latch Home Position Test".
  - Perform the BODY VERIFICATION TEST. Refer to DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
CHECK THE (Q79) SECTOR SWITCH SENSE CIRCUIT FOR A SHORT TO GROUND

Fig 4: Checking Sector Switch Sense Circuit For A Short To Ground
Courtesy of CHRYSLER LLC
1. Disconnect the Power Liftgate Module C2 harness connector.
2. Measure the resistance between ground and the (Q79) Sector Switch Sense circuit.
3. Wiggle the harness while observing the ohmmeter.
  Is the resistance below 1000.0 Ohms?
  
  Yes
  - Repair the (Q79) Sector Switch Sense circuit for a short to ground.
  - Perform the BODY VERIFICATION TEST. Refer to DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
  No
  - Replace the Power Liftgate Module in accordance with the Service Information.
  - Perform the BODY VERIFICATION TEST. Refer to DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .