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 DIAGNOSTIC TROUBLE CODE (DTC)
NOTE:
In this test, do not erase any DTCs until instructed to do so.
1. Turn the ignition on.
2. With the scan tool, read the active DTCs.
  Does the scan tool display this DTC as active?
  
  Yes
  - Go To 2
  No
  - Go To 6
VERIFY PCM IS ACTIVE ON THE CAN BUS
1. With the scan tool, select ECU View.
2. Verify that the PCM is active on the bus.
  Is the PCM active on the bus?
  
  Yes
  - Go To 3
  No
  - Refer to NO RESPONSE FROM PCM (POWERTRAIN CONTROL MODULE) - 2.4L or NO RESPONSE FROM PCM (POWERTRAIN CONTROL MODULE) - 3.2L and perform the No Response from PCM diagnostic procedure.
VERIFY IF THIS DTC SET IN OTHER MODULES
1. With the scan tool, read all active DTCs from all modules.
  Are any other modules on the CAN BUS reporting; U0401-00-IMPLAUSIBLE DATA RECEIVED FROM ECM/PCM?
  
  Yes
  - Replace and PROXI the Powertrain Control Module (PCM) in accordance with the Service Information. Refer to MODULE, POWERTRAIN CONTROL (PCM), REMOVAL .
  - Perform the PCM VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 2.4L or POWERTRAIN VERIFICATION TEST, 3.2L .
  No
  - Go To 4
CHECK FOR ANY OF THE FOLLOWING ACTIVE DTCS
1. With the scan tool, read all active DTCs from all modules.
  NOTE:
  Check for any PROXI, CAN hardware electrical, VIN Missing/Mismatch, battery or ignition related DTCs.
  
  Does the scan tool display any active DTCs to the conditions listed above?
  
  Yes
  - Go to and perform the appropriate diagnostic procedure(s).
  No
  - Go To 5
DTCS ACTIVE IN THE PCM
1. With the scan tool, read ACTIVE PCM DTCs.
  Are any DTCs active in the PCM?
  
  Yes
  - Refer to NO RESPONSE FROM PCM (POWERTRAIN CONTROL MODULE) - 2.4L or NO RESPONSE FROM PCM (POWERTRAIN CONTROL MODULE) - 3.2L and perform the appropriate diagnostic procedure.
  No
  - Replace and program the HVAC Module in accordance with the Service Information. Refer to MODULE, HVAC, REMOVAL .
  - Perform the HVAC VERIFICATION TEST. Refer to HVAC VERIFICATION TEST .
CHECK THE WIRING AND CONNECTORS
1. The conditions necessary to set the DTC are not present at this time.
2. With the scan tool, check the Environmental Data to help identify the conditions in which the DTC was set.
3. 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.
4. Wiggle the wiring and connectors while checking for shorted and open circuits.
  Were there any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To 7
CHECK VEHICLE HISTORY.
1. Check the repair history of this vehicle to see if this DTC was recorded previously in this module.
  Was this DTC present in this vehicle at a previous visit?
  
  Yes
  - Replace and PROXI the module that set this DTC in accordance with the Service Information. Perform its respective verification test.
  No
  - Record this information on the service order. Test complete.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .