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, clear DTCs in the Powertrain Control Module (PCM).
3. Test drive the vehicle under the conditions in which the DTC is monitored, as outlined above.
4. With the scan tool, read DTCs.
  Is the DTC Active or Pending at this time?
  
  Yes
  - Go To 2
  No
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
CHECK THE (K78) VVT INTAKE SOLENOID 2/1 CONTROL CIRCUIT FOR A SHORT TO VOLTAGE
1. Turn the ignition off.
2. Disconnect the VVT Intake Solenoid 2/1 harness connector.
3. Turn the ignition on.
4. Measure the voltage of the (K78) VVT Intake Solenoid 2/1 Control circuit at the VVT Intake Solenoid 2/1 harness connector.
  NOTE:
  The VVT Solenoid Control circuit is a PWM circuit which will read approximately 8.8 volts with ignition on and the solenoid disconnected.
  
  Is the voltage equal to battery voltage?
  
  Yes
  - Repair the (K78) VVT Intake Solenoid 2/1 Control circuit for a short to voltage.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 3.2L .
  No
  - Go To 3
CHECK THE (K78) VVT INTAKE SOLENOID 2/1 CONTROL CIRCUIT FOR A SHORT TO GROUND
1. Turn the ignition off.
2. Disconnect the PCM C2 harness connector.
3. Measure the resistance between ground and the (K78) VVT Intake Solenoid 2/1 Control circuit at the VVT Intake Solenoid 2/1 harness connector.
  Is the resistance above 10k Ohms?
  
  Yes
  - Go To 4
  No
  - Repair the (K78) VVT Exhaust Solenoid 2/1 Control circuit for a short to ground.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 3.2L .
CHECK THE (K78) VVT INTAKE SOLENOID 2/1 CONTROL CIRCUIT FOR AN OPEN/HIGH RESISTANCE
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.
1. Connect the (special tool #10436, Adapter, GPEC Diagnostic).
2. Measure the resistance of the (K78) VVT Intake Solenoid 2/1 Control circuit between the VVT Intake Solenoid 2/1 harness connector and the GPEC Adaptor.
  Is the resistance below 5.0 Ohms?
  
  Yes
  - Go To 5
  No
  - Repair the (K78) VVT Intake Solenoid 2/1 Control circuit for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 3.2L .
CHECK THE GROUND CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Measure the resistance between ground and the (Z904) Ground circuit at the VVT Intake Solenoid 1/1 harness connector.
  Is the resistance below 5.0 Ohms?
  
  Yes
  - Go To 6
  No
  - Repair the (Z904) Ground circuit for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 3.2L .
CHECK THE PCM VVT INTAKE SOLENOID 2/1 CIRCUIT INTERNAL DRIVER OPERATION
1. Connect the PCM C2 harness connector.
2. Turn the ignition on.
3. Using a 12-volt test light connected to ground, probe the (K78) VVT Intake Solenoid 2/1 Control circuit in the VVT Intake Solenoid 2/1 harness connector.
  NOTE:
  The PCM will command the solenoid ON briefly after the ignition is turned on. This is a normal condition. The test light will illuminate briefly and then turn off and stay off if there is not a short to voltage.
4. With the scan tool, actuate the VVT Intake Solenoid 2/1 to the ON (maximum) position.
  NOTE:
  The test light should be illuminated and bright. Compare the brightness to that of a direct connection to the battery.
  
  Is the test light illuminated and bright?
  
  Yes
  - Go To 7
  No
  - Go To 8
CHECK THE VVT INTAKE SOLENOID WIRING AND CONNECTOR
1. Turn the ignition off.
2. Inspect the wiring and connectors between the VVT Intake Solenoid 2/1 and the PCM.
3. Verify that there is good pin to terminal contact in the VVT Intake Solenoid 2/1 and PCM harness connectors.
4. Look for any chafed, pierced, pinched, or partially broken wires.
5. Look for broken, bent, pushed out, or corroded terminals.
6. Look for signs of water intrusion past the connector seal.
  Were any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 3.2L .
  No
  - Replace the VVT Intake Solenoid 2/1 in accordance with the service information.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 3.2L .
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, 3.2L .
  No
  - The wiring or poor connection problem has been repaired.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 3.2L .