Diagnostic Test

WARNING: This page is about a different car, the 2024 Jeep Grand Wagoneer L and 2024 Jeep Grand Wagoneer. However, it is still accessible from the selected car via links, so may be relevant.

READ AND RECORD DTCS AND ENVIRONMENTAL DATA - ERASE DTCS AND CHECK FOR THE DTC TO RETURN
1. With the scan tool, read DTCs in all Electronic Control Units (ECUs) and record on the repair order.
2. For future reference, run and save a vehicle Scan Report and all related recorded data.
3. With the scan tool, erase all DTCs.
4. Turn the ignition off for a minimum of 10.0 seconds.
5. Turn the ignition on.
6. Using the When Monitored and Set Conditions above and recorded data, operate the vehicle in the conditions that set the DTC.
7. With the scan tool, read DTCs.
  Did the DTC return?
  
  Yes
  - Go To 2
  No
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
CHECK THE INTAKE AIR TEMPERATURE SENSOR 3 BANK 1 (K120) SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE
1. Turn the ignition off.
2. Disconnect the Intake Air Temperature Sensor 3 Bank 1 harness connector.
3. Turn the ignition on.
4. Measure the voltage on the Intake Air Temperature Sensor 3 Bank 1 (K120) Signal circuit at the Intake Air Temperature Sensor 3 Bank 1 harness connector.
  Is the voltage above 5.2 volts?
  
  Yes
  - Repair the Intake Air Temperature Sensor 3 Bank 1 (K120) Signal circuit for a short to voltage.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 3
CHECK THE INTAKE AIR TEMPERATURE SENSOR 3 BANK 1 (K120) SIGNAL FOR AN OPEN/HIGH RESISTANCE
1. Turn the ignition off.
2. Disconnect the PCM harness connectors.
3. Measure the resistance of the Intake Air Temperature Sensor 3 Bank 1 (K120) Signal circuit between the Intake Air Temperature Sensor 3 Bank 1 harness connector and the PCM connector.
  Is the resistance below 3.0 Ohms?
  
  Yes
  - Go To 4
  No
  - Repair the Intake Air Temperature Sensor 3 Bank 1 (K120) Signal circuit for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK THE (K917) RETURN CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Measure the resistance of the (K917) Return circuit between the Sensor harness connector and the PCM connector.
  Is the resistance below 3.0 Ohms?
  
  Yes
  - Go To 5
  No
  - Repair the (K917) Return circuit for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
INTAKE AIR TEMPERATURE SENSOR 3 BANK 1
1. Reconnect the PCM harness connector.
2. Connect a jumper between the Intake Air Temperature Sensor 3 Bank 1 (K120) Signal circuit and the (K917) Return at the Intake Air Temperature Sensor 3 Bank 1 harness connector.
3. Turn the ignition on.
4. With the scan tool, read DTCS.
  NOTE:
  The SENSOR SIGNAL CIRCUIT LOW DTC should be active or pending with the jumper in place.
  
  Does the scan tool display as described above?
  
  Yes
  - Replace the Intake Air Temperature Sensor 3 Bank 1 in accordance with the Service Information.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 6
POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Intake Air Temperature Sensor 3 Bank 1 and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched, or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals.
4. Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.
5. Look for the data to change or for the DTC to reset during the wiggle test.
6. Perform any Service Bulletins that may apply.
  Were any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Replace and program the Powertrain Control Module (PCM) in accordance with the Service Information. Refer to MODULE, POWERTRAIN CONTROL (PCM), REMOVAL AND INSTALLATION .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .