Diagnostic Test

DIAGNOSTIC TROUBLE CODE (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. 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 B1972-POWER LIFTGATE LATCH RELEASE - RATCHET PRIMARY 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
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 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 4
CHECK THE (Q901) LOGIC GROUND CIRCUIT FOR AN OPEN

Fig 1: Checking Logic Ground Circuit For An Open
Courtesy of CHRYSLER LLC
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 step 5
  No
  - Repair the (Q901) Logic Ground circuit for an open.
  - Perform the BODY VERIFICATION TEST. Refer to DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
(G78) LIFTGATE AJAR SWITCH SENSE CIRCUIT OPEN

Fig 2: Checking Liftgate Ajar Switch Sense Circuit Open
Courtesy of CHRYSLER LLC
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 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?
  
  Yes
  - Go to step 6
  No
  - Repair the (G78) Liftgate Ajar Switch Sense circuit for an open.
  - Perform the BODY VERIFICATION TEST. Refer to DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
(G78) LIFTGATE AJAR SWITCH SENSE CIRCUIT SHORTED TO VOLTAGE

Fig 3: Checking Liftgate Ajar Switch Sense Circuit Shorted To Voltage
Courtesy of CHRYSLER LLC
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. Refer to DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
  No
  - 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 .