Diagnostic Test

WARNING: This page is about a different car, the 2017 Jeep Cherokee. However, it is still accessible from the selected car via links, so may be relevant.

CHECK FOR ACTIVE DTCS
1. With the scan tool, record the DTCs and any liftgate inhibitors.
2. Erase the DTCs.
3. Turn the ignition off, wait 10 seconds, then turn the ignition on.
4. Operate the liftgate several times.
5. With the scan tool, read the Active DTCs.
  Does the scan tool display; B1964-12-POWER LIFTGATE SENSOR SUPPLY - CIRCUIT SHORT TO BATTERY?
  
  Yes
  - Go To 2
  No
  - Test complete, the condition or conditions that originally set this DTC are not present at this time. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals and poor pin fit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
ISOLATE AND CHECK THE (Q901) LOGIC GROUND CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. The ignition must be off when checking the continuity of a circuit.
2. Isolate the circuit by disconnecting the Power Liftgate Module C2 harness connector containing the circuit being tested. Note: Use the wiring diagram as a guide to follow the path of the circuit.
3. Before measuring the resistance of any circuit, first measure the resistance between the two leads of the DVOM. Note: The meter leads can add resistance to the measurement value.
4. Connect one lead of the DVOM to the circuit being tested at the component harness connector.
5. Connect the other lead to the circuit being tested and measure the resistance of the circuit.
  Is the resistance below 1.0 Ohm on both?
  
  Yes
  - Go To 3
  No
  - Repair the (Q901) Logic Ground circuit for an open.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
ISOLATE AND CHECK THE (Q203) POSITION SENSOR SUPPLY CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. The ignition must be off when checking the continuity of a circuit.
2. Isolate the circuit by disconnecting the Power Liftgate Module C1 harness connector containing the circuit being tested. Note: Use the wiring diagram as a guide to follow the path of the circuit.
3. Before measuring the resistance of any circuit, first measure the resistance between the two leads of the DVOM. Note: The meter leads can add resistance to the measurement value.
4. Connect one lead of the DVOM to the circuit being tested at the component harness connector.
5. Connect the other lead to the circuit being tested and measure the resistance of the circuit.
  Is the resistance below 1.0 Ohms?
  
  Yes
  - Replace the Power Liftgate Module in accordance with the Service Information. Refer to MODULE, POWER LIFTGATE CONTROL (PLGM), REMOVAL .
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Repair the (Q203) Position Sensor Supply circuit for an open.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
CHECK THE (Q203) POSITION SENSOR SUPPLY CIRCUIT FOR A SHORT TO VOLTAGE
1. Turn the ignition off.
2. Disconnect the harness connector at the component of the circuit being tested. Note: Use the wiring diagram as a guide to follow the path of the circuit.
3. Turn the ignition on.
4. Measure the voltage between the (Q901) Logic Ground circuit and the (Q203) Position Sensor Supply circuit in the Power Liftgate Drive Unit connector.
  Is the voltage above 5.5 volts?
  
  Yes
  - Repair the (Q203) Position Sensor Supply circuit for a short to voltage. If the power liftgate is inoperative after repairing the (Q203) Position Sensor Supply circuit. Replace the Power Liftgate Module in accordance with the Service Information. Refer to MODULE, POWER LIFTGATE CONTROL (PLGM), REMOVAL .
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Replace the Power Liftgate Drive Unit in accordance with the Service Information. Refer to DRIVE UNIT, POWER, REMOVAL .
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .