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, with the scan tool, 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 .
VERIFY THAT THE HOOD IS SECURED PROPERLY
1. Visually inspect that the Hood is secured properly. Also inspect the Hood Ajar Switch and Hood Latch Assembly for proper installation.
  Were any problems found?
  
  Yes
  - Perform the appropriate repair.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 3
CHECK THE HOOD AJAR SWITCH INPUTS
1. Monitor the Hood Ajar Switch 1 (Hood Latch) and Hood Ajar Switch 2 (Plunger) states on the scan tool to determine which switch is not changing properly.
  Which Hood Ajar Switch is not reading properly?
  
  Hood Ajar Switch 1 (Hood Latch)
  - Go To 4
  Hood Ajar Switch 2 (Plunger)
  - Go To 9
CHECK THE HOOD AJAR SWITCH 1 (HOOD LATCH) CONNECTOR AND TERMINALS
1. Turn the ignition off.
2. Check the Hood Ajar Switch 1 (Hood Latch) harness connector for proper connection at the Hood Latch Assembly.
3. Verify that the connector is completely plugged in and properly locked prior to disconnecting.
4. Disconnect the Hood Ajar Switch 1 (Hood Latch) harness connector and check for any pushed out, damaged or spread terminals.
  Were any issues found with the connector or terminals?
  
  Yes
  - Repair the damaged terminal or properly connect and lock the Hood Ajar Switch 1 (Hood Latch) harness connector and retest for DTCs.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 5
CHECK THE HOOD AJAR SWITCH 1 (HOOD LATCH) FOR PROPER FUNCTION
1. Check the Hood Ajar Switch 1 (Hood Latch) functionality. Use the Hood Ajar Switch 1 (Hood Latch) diagnostic and technical information provided above.
  Is the Hood Ajar Switch 1 (Hood Latch) functioning properly?
  
  Yes
  - Go To 6
  No
  - Replace the Hood Latch Assembly in accordance with the Service Information.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
ISOLATE AND CHECK THE HOOD AJAR SWITCH 1 (G70) SENSE CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. The ignition must be off when checking the continuity of a circuit.
2. Isolate the circuit by disconnecting the Electronic Control Unit (ECU) and the component harness connector containing the circuit being tested. Note: Use the wiring diagram as a guide to follow the path of the circuit.
3. Before measuring the resistance of any circuit, first measure the resistance between the two leads of the DVOM. Note: The meter leads can add resistance to the measurement value.
4. Connect one lead of the DVOM to the circuit being tested at the component harness connector.
5. Connect the other lead to the circuit being tested at the ECU harness connector and measure the resistance of the circuit.
  Is the resistance below 3.0 Ohms?
  
  Yes
  - Go To 7
  No
  - Repair the circuit for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
ISOLATE AND CHECK THE HOOD AJAR SWITCH 1 (G931) SENSOR GROUND CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. The ignition must be off when checking the continuity of a circuit.
2. Isolate the circuit by disconnecting the Electronic Control Unit (ECU) and the component harness connector containing the circuit being tested. Note: Use the wiring diagram as a guide to follow the path of the circuit.
3. Before measuring the resistance of any circuit, first measure the resistance between the two leads of the DVOM. Note: The meter leads can add resistance to the measurement value.
4. Connect one lead of the DVOM to the circuit being tested at the component harness connector.
5. Connect the other lead to the circuit being tested at the ECU harness connector and measure the resistance of the circuit.
  Is the resistance below 3.0 Ohms?
  
  Yes
  - Go To 8
  No
  - Repair the circuit for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK RELATED BCM AND COMPONENT CONNECTIONS
1. Disconnect all BCM 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. Reconnect all BCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
6. Reconnect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
7. Reconnect 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 Body Control Module (BCM) in accordance with the Service Information. Refer to MODULE, BODY CONTROL (BCM), REMOVAL AND INSTALLATION .
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - The wiring or poor connection problem has been repaired.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
CHECK THE HOOD AJAR SWITCH 2 (PLUNGER) FOR PROPER FUNCTION
1. Check the Hood Ajar Switch 2 (Plunger) functionality. Use the Hood Ajar Switch 2 (Plunger) diagnostic and technical information provided above.
  Is the Hood Ajar Switch 2 (Plunger) functioning properly?
  
  Yes
  - Go To 10
  No
  - Replace the Hood Ajar Switch 2 (Plunger) in accordance with the Service Information.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
ISOLATE AND CHECK THE HOOD AJAR SWITCH 2 (K806) POSITION SIGNAL CIRCUIT FOR A SHORT TO GROUND
1. The ignition must be off when checking a circuit for continuity to ground.
2. Isolate the circuit by disconnecting the Electronic Control Unit (ECU) and every component harness connector containing the circuit being tested. Note: Use the wiring diagram as a guide to follow the path of the circuit.
3. Connect the negative lead of the DVOM to a known good ground.
4. With the positive lead of the DVOM, probe the circuit being tested at the component harness connector and check for continuity between the circuit and ground.
  NOTE:
  There should be no continuity between ground and the circuit being tested.
  
  Is there continuity between ground and the circuit being tested?
  
  Yes
  - Repair the circuit for a short to ground or short to the sensor ground circuit. Use the wiring diagram as a guide to trace the circuit and look for any in-line connectors to help isolate the location of the short.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 11
CHECK RELATED PCM AND COMPONENT CONNECTIONS
1. Perform any Service Bulletins that apply.
2. Disconnect all PCM harness connectors.
3. Disconnect all related in-line harness connections (if equipped).
4. Disconnect the related component harness connectors.
5. 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.
6. Reconnect all PCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
7. Reconnect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
8. Reconnect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
9. With the scan tool, erase DTCs.
10. Test drive or operate the vehicle in accordance with the when monitored and set conditions.
11. 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 AND INSTALLATION .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - The wiring or poor connection problem has been repaired.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .