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.

TEST FOR INTERMITTENT CONDITION
NOTE:
Check for any TSB(s) related to the condition. If a TSB applies, perform the procedure outlined in the TSB before continuing.
1. Turn the ignition on.
  NOTE:
  Make sure the battery voltage is between 10.0 and 16.0 volts.
2. With the scan tool, read the module status.
  NOTE:
  Check the BCM for any active CAN C hardware DTCs, perform DTC before proceeding.
  
  Does the scan tool indicate that the module is active on the bus?
  
  Yes
  - The no response condition is 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 correct pin tension.
  No
  - Go To 2
CHECK THE (Z915) GROUND CIRCUIT FOR AN OPEN
1. Turn the ignition off.
2. Disconnect the Adaptive Cruise Control Module harness connector.
3. Using a 12-volt test light connected to 12-volts, check the (Z915) Ground circuit.
  Does the test light illuminate brightly?
  
  Yes
  - Go To 3
  No
  - Repair the (Z915) Ground circuit for an open.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
CHECK THE (F948) FUSED IGNITION CIRCUIT FOR AN OPEN OR SHORT
1. Turn the ignition on.
2. Using a 12-volt test light connected to ground, check the (F948) Fused Ignition circuit.
  Does the test light illuminate brightly?
  
  Yes
  - Go To 4
  No
  - Repair the (F948) Fused Ignition circuit for an open.
    NOTE:
    If the fuse is open, make sure to check the circuit for a short to ground.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
CHECK THE (D249) AND (D248) CAN C BUS CIRCUITS FOR AN OPEN
1. Turn the ignition off.
2. Disconnect the dash CAN C C6 Star harness connector.
3. Measure the resistance of the (D249) CAN C Bus (+) circuit between the Star C6 harness connector and the Adaptive Cruise Control Module harness connector.
4. Measure the resistance of the (D248) CAN C Bus (-) circuit between the Star C6 harness connector and the Adaptive Cruise Control Module harness connector.
  Are the resistances below 5.0 Ohms?
  
  Yes
  - Replace and program the Adaptive Cruise Control (ACC) module in accordance with the Service Information. Refer to MODULE, ADAPTIVE CRUISE CONTROL (ACCM), REMOVAL .
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Repair the (D249) or (D248) CAN C Bus circuit for an open.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .