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 and allow it 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.
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 INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
CHECK FOR OTHER DTCS
1. Refer to the recorded DTCs.
  Are there any 5-Volt Reference DTCs active or pending?
  
  Yes
  - Perform the applicable diagnostic procedure(s). Refer to 2.4L - DIAGNOSTIC CODE INDEX .
  No
  - Go To 3
CHECK THE (F856) 5-VOLT SUPPLY CIRCUIT FOR A SHORT TO GROUND
1. Turn the ignition off.
2. Disconnect the MAP Sensor harness connector.
3. Disconnect the PCM C2 harness connector.
4. Check for continuity between ground and the (F856) 5-Volt Supply circuit at the MAP Sensor harness connector.
  Is there continuity between ground and the (F856) 5-Volt Supply circuit?
  
  Yes
  - Repair the (F856) 5-Volt Supply circuit for a short to ground.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 2.4L .
  No
  - Go To 4
CHECK FOR THE (F856) 5-VOLT SUPPLY CIRCUIT SHORTED TO THE (K900) SENSOR GROUND CIRCUIT
1. Check for continuity between the (F856) 5-Volt Supply circuit and the (K900) Sensor Ground circuit in the MAP Sensor harness connector.
  Is there continuity between the (F856) 5-Volt Supply circuit and the (K900) Sensor Ground circuit in the MAP Sensor harness connector?
  
  Yes
  - Repair the (F856) 5-Volt Supply circuit for a short to the (K900) Sensor Ground circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 2.4L .
  No
  - Go To 5
CHECK THE (F856) 5-VOLT CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Measure the resistance of the (F856) 5-Volt Supply circuit between the Throttle Body harness connector and the PCM C2 harness connector.
  Is the resistance below 3.0 Ohms?
  
  Yes
  - Go To 6
  No
  - Repair the (F856) 5-Volt Supply circuit for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 2.4L .
CHECK THE (K1) MAP SENSOR SIGNAL CIRCUIT 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 (K1) MAP Sensor Signal circuit in the MAP Sensor harness connector.
  Is there continuity between ground and the (K1) MAP Sensor Signal circuit?
  
  Yes
  - Repair the (K1) MAP Sensor Signal circuit for a short to ground.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 2.4L .
  No
  - Go To 7
CHECK FOR THE (K1) MAP SENSOR SIGNAL CIRCUIT SHORTED TO THE (K900) SENSOR GROUND CIRCUIT
1. Check for continuity between the (K1) MAP Sensor Signal circuit and the (K900) Sensor Ground circuit in the MAP Sensor harness connector.
  Is there continuity between the (K1) MAP Sensor Signal circuit and the (K900) Sensor Ground circuit in the MAP Sensor harness connector?
  
  Yes
  - Repair the (K1) MAP Sensor Signal circuit for a short to the (K900) Sensor Ground circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 2.4L .
  No
  - Go To 8
CHECK THE ABILITY OF THE PCM TO READ THE MAP SENSOR VALUE USING A JUMPER
1. Turn the ignition off.
2. Reconnect the PCM C2 harness connector.
3. Connect a jumper between the (F856) 5-Volt Supply circuit and the (K1) MAP Sensor Signal circuit in the MAP Sensor harness connector.
4. Turn the ignition on.
5. With the scan tool, read the MAP Sensor signal voltage.
  Is the voltage above 4.8 volts with the jumper in place?
  
  Yes
  - Replace the MAP Sensor in accordance with the Service Information. Refer to SENSOR, MANIFOLD AIR PRESSURE (MAP), REMOVAL .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 2.4L .
  No
  - Go To 9
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 .