Diagnostic Test

2008 Jeep Commander Limited, 5.7 2, RWDSECTION Diagnostic Test
  1. DTC PRESENT 
    NOTE: This DTC will only set during the latching operation after the four second time out. This may make it difficult to reproduce.

    With the scan tool, record and erase DTC's.

    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 ACTIVE DTCs.

    Does the scan tool display B1976-POWER LIFTGATE LATCH RELEASE - RATCHET SECONDARY SWITCH PERFORMANCE? 

    Yes 

    1. Go To  2.

    No 

    1. 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.
    2. Perform BODY VERIFICATION TEST .
  2. 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 

    1. Refer to Service information for the related symptom(s).
    2. Perform BODY VERIFICATION TEST .

    No 

    1. Go To  3.
  3. POWER LIFTGATE MODULE 

    With the scan tool, monitor the SECONDARY RATCHET SWITCH CLOSED.

    Using a screwdriver, click the latch to the first detent while observing the scan tool.

    Unlatch the latch by pressing the handle switch and observe the scan tool for a change of state.

    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 

    1. Go To  4.

    Yes 

    1. Replace the Power Liftgate Module in accordance with the service information.
    2. Perform BODY VERIFICATION TEST .
  4. CHECK THE (Q901) LOGIC GROUND CIRCUIT FOR AN OPEN 
    Fig 1: Measuring Resistance Between Ground And (Q901) Logic Ground Circuit
    GC0044255Courtesy of CHRYSLER LLC

    Turn the ignition off.

    Disconnect the Power Liftgate Latch harness connector.

    Measure the resistance between ground and the (Q901) Logic Ground circuit.

    Wiggle the harness while observing the ohmmeter.

    Is the resistance below 9.5 ohms? 

    Yes 

    1. Go To  5.

    No 

    1. Repair the (Q901) Logic Ground circuit for an open.
    2. Perform BODY VERIFICATION TEST .
  5. CHECK THE (Q76) LATCH SECONDARY POSITION SENSE CIRCUIT FOR A SHORT TO GROUND 
    Fig 2: Measuring Resistance Between Ground And (Q76) Latch Secondary Position Sense Circuit
    GC0044258Courtesy of CHRYSLER LLC

    Measure the resistance between ground and the (Q76) Latch Secondary Position Sense circuit.

    Wiggle the harness while observing the ohmmeter.

    Is the resistance below 10000.0 ohms? 

    No 

    1. Go To  6.

    Yes 

    1. Repair the (Q76) Latch Secondary Position Sense circuit for a short to ground.
    2. Perform BODY VERIFICATION TEST .
  6. CHECK THE (Q76) LATCH SECONDARY POSITION SENSE CIRCUIT FOR AN OPEN 
    Fig 3: Measuring Resistance Of (Q76) Latch Secondary Position Sense Between Power Liftgate Module C2 Harness Connector And Power Liftgate Latch Harness Connector
    GC0044219Courtesy of CHRYSLER LLC

    Disconnect the Power Liftgate Module C2 harness connector.

    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.

    Wiggle the harness while observing the ohmmeter.

    Is the resistance below 2.0 ohms? 

    No 

    1. Repair the (Q76) Latch Secondary Position Sense circuit for an open.
    2. Perform BODY VERIFICATION TEST .

    Yes 

    1. Go To  7.
  7. CHECK THE (Q76) LATCH SECONDARY POSITION SENSE CIRCUIT FOR A SHORT TO VOLTAGE 
    Fig 4: Measuring Voltage Of (Q76) Latch Secondary Position Sense Circuit
    GC0044259Courtesy of CHRYSLER LLC

    Turn the ignition on.

    Measure the voltage of the (Q76) Latch Secondary Position Sense circuit.

    Wiggle the harness while observing the voltmeter.

    Is there any voltage present? 

    No 

    1. Go To  8.

    Yes 

    1. Repair the (Q76) Latch Secondary Position Sense circuit for a short to voltage.
    2. Perform BODY VERIFICATION TEST .
  8. POWER LIFTGATE DRIVE UNIT 
    Fig 5: Power Liftgate Drive Unit Connector
    GC0048970Courtesy of CHRYSLER LLC

    Disconnect the Power Liftgate Drive Unit harness connector

    Erase DTCs.

    Turn the ignition off, wait 10 seconds, then turn the ignition on.

    With the scan tool, read DTCs.

    Does the scan tool display this DTC? 

    Yes 

    1. Replace the Power Liftgate Module in accordance with the service information.
    2. Perform BODY VERIFICATION TEST .

    No 

    1. Replace the Power Liftgate Drive Unit in accordance with the service information.
    2. Perform BODY VERIFICATION TEST .
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.