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
1. Turn the ignition on.
2. With the scan tool, read DTCs and record on the repair order.
  Is the DTC active or pending?
  
  Yes
  - Go To 2
  No
  - Perform the CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure. Refer to INTERMITTENT CONDITION .
CHECK FOR OTHER DTCS
NOTE:
Using an unapproved block heater in cold temperatures may cause this DTC to set. No repair is required.
1. Refer to the recorded DTCs.
  Are there any AAT, ECT, and IAT Sensor DTCs active or pending?
  
  Yes
  - Perform the applicable diagnostic procedure(s). Refer to 2.4L - DIAGNOSTIC CODE INDEX .
  No
  - Go To 3
CHECK THE READINGS FOR THE TEMPERATURE SENSORS
NOTE:
Allow the engine sit for 6 - 8 hours before testing.
1. Turn the ignition on.
2. With a scan tool, monitor the AAT, ECT, and IAT Sensor values.
3. Start the engine.
4. Allow the engine to reach normal operating temperature.
  Does the value for each of the sensors increase smoothly and as expected?
  
  Yes
  - Perform the CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure. Refer to INTERMITTENT CONDITION .
  No
  - Go To 4
CHECK THE ABILITY OF THE PCM TO READ THE TEMPERATURE SENSOR SIGNAL
NOTE:
If it is necessary to replace the AAT Sensor, be sure to drive the vehicle over 30 mph for at least 5 minutes to update the AAT value.
1. Turn the ignition on.
2. Disconnect the harness connector for the sensor that had a value which did not increase smoothly and as expected.
3. With the scan tool, read the sensor voltage with the connector disconnected.
  NOTE:
  The sensor voltage should be approximately 5.0 volts with the connector disconnected.
4. Connect a jumper between the sensor signal circuit and the sensor ground circuit in the harness connector.
5. With the scan tool, read the sensor voltage with the jumper in place.
  NOTE:
  The sensor voltage should be approximately 0 volts with the jumper in place.
  
  Does the sensor voltage change as described?
  
  Yes
  - Replace the sensor.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 2.4L .
  No
  - Go To 5
CHECK THE SENSOR SIGNAL CIRCUIT FOR HIGH RESISTANCE
1. Turn the ignition off.
2. For the AAT Sensor, disconnect the BCM harness connector. Otherwise disconnect the PCM harness connector.
  CAUTION:
  Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install the GPEC Diagnostic Adaptor to perform the diagnosis.
3. Connect the (special tool #10436, Adapter, GPEC Diagnostic).
4. Measure the resistance of the Sensor Signal circuit between the sensor harness connector and the GPEC Adaptor or BCM harness connector.
  Is the resistance below 3.0 Ohms?
  
  Yes
  - Go To 6
  No
  - Repair the Sensor Signal circuit for high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 2.4L .
CHECK THE SENSOR GROUND CIRCUIT FOR HIGH RESISTANCE
1. Measure the resistance of the Sensor Ground circuit between the suspect sensor harness connector and the GPEC Adaptor or BCM harness connector.
  Is the resistance below 3.0 Ohms?
  
  Yes
  - Go To 7
  No
  - Repair the Sensor Ground circuit for high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 2.4L .
CHECK RELATED HARNESS CONNECTIONS
1. Disconnect all PCM harness connectors.
2. Disconnect all related in-line harness connections (if equipped).
3. Disconnect the related component harness connectors.
4. Inspect harness connectors, component connectors, and all male and female terminals for the following conditions:
  - Proper connector installation.
  - Damaged connector locks.
  - Corrosion.
  - Other signs of water intrusion.
  - Weather seal damage (if equipped).
  - Bent terminals.
  - Overheating due to a poor connection (terminal may be discolored due to excessive current draw).
  - Terminals that have been pushed back into the connector cavity.
  - Check for spread terminals and verify proper terminal tension.
  Repair any conditions that are found.
5. Connect all PCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
6. Connect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
7. Connect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
8. With the scan tool, erase DTCs.
9. Test drive or operate the vehicle in accordance with the when monitored and set conditions.
10. With the scan tool, read DTCs.
  Did the DTC return?
  
  Yes
  - Replace and program the Powertrain Control Module (PCM) in accordance with the Service Information. Refer to MODULE, POWERTRAIN CONTROL (PCM), REMOVAL, 2.4L/3.2L .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 2.4L .
  No
  - The wiring or poor connection problem has been repaired.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 2.4L .