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. Start the engine.
2. Allow the engine to reach normal operating temperature.
  WARNING:
  When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing. Failure to follow these instructions may result in possible serious or fatal injury.
3. With a scan tool, read DTCs and record on the repair order.
  NOTE:
  It may be necessary to drive the vehicle to meet the conditions to set this DTC, try to repeat the conditions in which the fault originally set by reviewing the Freeze Frame data.
  
  Is the DTC active or pending?
  
  Yes
  - Go To 2
  No
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
CHECK FOR OTHER DTCS
NOTE:
This DTC will set due to poor engine performance as well as a faulty O2 Sensor. If the vehicle exhibits any fuel system or driveability issues, or has any other driveability DTCs present, repair those concerns before proceeding with this test.
1. Refer to the recorded DTCs.
  Are there any other fuel system or driveability DTCs active or pending?
  
  Yes
  - Perform the applicable diagnostic procedure(s). Refer to 2.4L - DIAGNOSTIC CODE INDEX .
  No
  - Go To 3
CHECK THE EXHAUST SYSTEM FOR LEAKS
1. Perform the CHECKING THE EXHAUST SYSTEM FOR LEAKS test procedure. Refer to CHECKING THE EXHAUST SYSTEM FOR LEAKS .
  Were any exhaust leaks found?
  
  Yes
  - Repair or replace the leaking exhaust parts as necessary.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 2.4L .
  No
  - Go To 4
CHECK THE O2 SENSOR 1/1 CIRCUITS FOR A SHORT TO VOLTAGE
1. Turn the ignition off.
2. Disconnect the O2 Sensor 1/1 harness connector.
3. Turn the ignition on.
4. Measure for voltage at the:
  - (K41) O2 Sensor 1/1 Signal circuit at the O2 Sensor 1/1 harness connector.
  - (K902) O2 Sensor 1/1 Return circuit at the O2 Sensor 1/1 harness connector.
  - (K89) O2 Sensor 1/1 Positive Current Control circuit at the O2 Sensor 1/1 harness connector.
  Do any of the circuits measure above 0.5 volts?
  
  Yes
  - Repair the circuit that measured above 0.5 volts for a short to voltage.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 2.4L .
  No
  - Go To 5
CHECK THE O2 SENSOR 1/1 CIRCUITS FOR A SHORT TO GROUND
1. Turn the ignition off.
2. Disconnect the PCM C2 harness connector.
3. Check for continuity between ground and the:
  - (K41) O2 Sensor 1/1 Signal circuit at the O2 Sensor 1/1 harness connector.
  - (K902) O2 Sensor 1/1 Return circuit at the O2 Sensor 1/1 harness connector.
  - (K89) O2 Sensor 1/1 Positive Current Control circuit at the O2 Sensor 1/1 harness connector.
  - (K79) O2 Sensor 1/1 Heater Control circuit at the O2 Sensor 1/1 harness connector.
  Is there continuity between ground and any of the above listed circuits?
  
  Yes
  - Repair the circuit that showed continuity for a short to ground.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 2.4L .
  No
  - Go To 6
CHECK THE O2 SENSOR 1/1 CIRCUITS FOR AN OPEN OR HIGH RESISTANCE
1. Measure the resistance of the:
  - (K41) O2 Sensor 1/1 Signal circuit between the O2 Sensor 1/1 harness connector and the PCM C2 harness connector.
  - (K902) O2 Sensor 1/1 Return circuit between the O2 Sensor 1/1 harness connector and the PCM C2 harness connector.
  - (K89) O2 Sensor 1/1 Positive Current Control circuit between the O2 Sensor 1/1 harness connector and the PCM C2 harness connector.
  - (K79) O2 Sensor 1/1 Heater Control circuit between the O2 Sensor 1/1 harness connector and the PCM C2 harness connector.
  Is the resistance below 3.0 Ohms for each of the above circuits?
  
  Yes
  - Go To 7
  No
  - Repair the circuit that measured above 3.0 Ohms for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 2.4L .
REPLACE THE O2 SENSOR AND RETEST FOR DTC
1. Replace the O2 Sensor accordance with the Service Information. Refer to SENSOR, OXYGEN, REMOVAL, 2.4L .
2. Reconnect the O2 Sensor and PCM harness connectors.
3. Turn the ignition on.
4. With the scan tool, erase DTCs.
5. Start the engine and allow it to idle long enough for the O2 Sensor to enter closed loop operation.
6. With the scan tool, read DTCs.
  Did the DTC return?
  
  Yes
  - Go To 8
  No
  - Replacing the O2 Sensor repaired the fault.
  - 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 .