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 system voltage or 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 (K854) 5 VOLT SUPPLY CIRCUIT FOR A SHORT TO VOLTAGE
1. Turn the ignition off.
2. Disconnect the A/C Pressure Transducer harness connector.
3. Turn the ignition on.
4. Measure the voltage on the (K854) 5 Volt Supply circuit at the A/C Pressure Transducer harness connector.
  Is the voltage above 5.2 volts?
  
  Yes
  - Repair the (K854) 5 Volt Supply circuit for a short to voltage.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 2.4L .
  No
  - Go To 4
CHECK THE (C18) A/C PRESSURE SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE
1. Measure the voltage on the (C18) A/C Pressure Signal circuit at the A/C Pressure Transducer harness connector.
  Is the voltage above 5.2 volts?
  
  Yes
  - Repair the (C18) A/C Pressure Signal circuit for a short to voltage.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 2.4L .
  No
  - Go To 5
CHECK FOR THE (C18) A/C PRESSURE SIGNAL CIRCUIT SHORTED TO THE (K854) 5 VOLT SUPPLY CIRCUIT
1. Turn the ignition off.
2. Disconnect the PCM C1 harness connector.
3. Check for continuity between the (C18) A/C Pressure Signal circuit and the (K854) 5 Volt Supply circuit at the A/C Pressure Transducer harness connector.
  Is there continuity between the (C18) A/C Pressure Signal circuit and the (K854) 5 Volt Supply circuit?
  
  Yes
  - Go To 6
  No
  - Repair the (C18) A/C Pressure Signal circuit for a short to the (K854) 5 Volt Supply circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 2.4L .
CHECK THE (C18) A/C PRESSURE SIGNAL CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Turn the ignition off.
  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.
2. Connect the (special tool #10436, Adapter, GPEC Diagnostic).
3. Measure the resistance of the (C18) A/C Pressure Signal circuit between the A/C Pressure Transducer harness connector and the GPEC Adaptor.
  Is the resistance below 3.0 Ohms?
  
  Yes
  - Go To 7
  No
  - Repair the (C18) A/C Pressure Signal circuit for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 2.4L .
CHECK THE (K914) GROUND CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Measure the resistance of the (K914) Ground circuit between the A/C Pressure Transducer harness connector and the GPEC Adaptor.
  Is the resistance below 3.0 Ohms?
  
  Yes
  - Go To 8
  No
  - Repair the (K914) Ground circuit for an open circuit or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 2.4L .
CHECK THE ABILITY OF THE PCM TO READ THE A/C PRESSURE TRANSDUCER SIGNAL
1. Turn the ignition off.
2. Reconnect the PCM harness connectors.
3. Connect a jumper between the (K914) Sensor Ground circuit and the (C18) A/C Pressure Signal circuit at the A/C Pressure Transducer harness connector.
4. Turn the ignition on.
5. With the scan tool, read the A/C Pressure Transducer signal voltage.
  Is the voltage below 0.1 volt with the jumper in place?
  
  Yes
  - Replace the A/C Pressure Transducer in accordance with the Service Information.
  - 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 .