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 AN ACTIVE DTC
NOTE:
Disconnecting the Radio Frequency (RF) Hub Module results in a loss of ignition status messages and may cause scan tool communication concerns.
1. Turn the ignition on.
2. With the scan tool, read DTCs.
  Does the scan tool display this DTC as active?
  
  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 correct pin tension.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
CHECK THE (D58) CAN BUS (-) CIRCUIT FOR A SHORT TO VOLTAGE
1. Disconnect the scan tool.
2. Measure the voltage of the (D58) CAN C Bus (-) circuit between the Data Link Connector (DLC), pin 14 and ground.
  Is the voltage above 10.0 volts?
  
  Yes
  - Diagnose the short to voltage in the (D58) CAN C Bus (-) circuit. Use the Star Connectors to isolate portions of the bus to assist in determining the location of the concern. Repair the circuit concern or replace the module that when disconnected allowed the bus voltage to return to normal.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To 3
CHECK THE (D57) CAN C BUS (+) CIRCUIT FOR A SHORT TO GROUND
1. Measure the voltage of the (D57) CAN C Bus (+) circuit between the Data Link Connector (DLC), pin 6 and ground.
  Is the voltage approximately 0 volt?
  
  Yes
  - Diagnose the short to ground in the (D57) CAN C Bus (+) circuit. Use the Star Connectors to isolate portions of the bus to assist in determining the location of the concern. Repair the circuit concern or replace the module that when disconnected allowed the bus voltage to return to normal.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To 4
CHECK FOR CORRECT BUS TERMINATION RESISTANCE
1. Turn the ignition off.
2. Disconnect and isolate the negative battery cable.
3. Measure the resistance of the (D57) CAN C Bus (+) circuit and the (D58) CAN C Bus (-) circuit between DLC pins 6 and 14.
  Is the resistance between 53.5 and 67 Ohms?
  
  Yes
  - Test complete. The condition or conditions that originally caused this concern are not present at this time. Using the wiring diagrams as a guide, check the Star Connectors and all related splices for signs of water intrusion, corrosion, pushed out or bent terminals and correct pin tension.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - For a resistance measurement above 67 Ohms, an open or high resistance is present in the (D57) CAN C Bus (+) circuit or the (D58) CAN C Bus (-) circuit between the Star Connectors or one of the termination resistors internal to the Star Connector is damaged. Diagnose and repair as necessary.
  - For a resistance measurement below 53.5 Ohms, a short between the (D57) CAN C Bus (+) circuit and the (D58) CAN C Bus (-) is present. Diagnose the short between the (D57) CAN C Bus (+) circuit and the (D58) CAN C Bus (-) circuit. Use the Star Connectors to isolate portions of the bus to assist in determining the location of the concern. Repair the circuit concern or replace the module that when disconnected allowed the resistance to return to normal.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .