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 .
CHECK FOR OTHER DTCS
1. Refer to the recorded DTCs.
  NOTE:
  Any circuit related faults for any module on the vehicle may cause this DTC to set. All other circuit related DTCs should be resolved before continuing with this DTC.
  
  Are there any related LIN BUS, Alternator circuit or Loss of Communication with Alternator DTCs present?
  
  Yes
  - Perform the applicable diagnostic procedure(s). Refer to DIAGNOSTIC CODE INDEX .
  No
  - Go To 3
CHECK ALTERNATOR DRIVE BELT
1. Visually inspect the Alternator drive belt for glazing, cracks and other problems.
2. Inspect the Alternator drive belt and tensioner for proper tension.
  Were any problems found?
  
  Yes
  - Repair or replace as necessary.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 4

CHECK THE CONDITION OF THE BATTERY

NOTE:

Inspect the vehicle for aftermarket accessories that may exceed the Alternator System output.

Use the (special tool #GR8-1220KIT-CHRY, AGM Battery Tester/Charger Station) or equivalent to load test the Battery.

Courtesy of CHRYSLER GROUP, LLC

Did the Battery pass or fail?

Passed

Go To 5

Failed

Perform the appropriate repair according to the Battery tester.
Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

CHECK THE ALTERNATOR OUTPUT AT THE ALTERNATOR OUTPUT STUD
1. Start the engine.
2. With the scan tool, navigate to data display and monitor the target charging voltage.
3. Using a voltmeter, measure the voltage at the Alternator output stud (A801) Fused B+ circuit.
  Is the Alternator output more than 1.0 volt below the target charging voltage?
  
  Yes
  - Go To 6
  No
  - Replace the Alternator in accordance with the Service Information. Refer to GENERATOR, REMOVAL AND INSTALLATION .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK THE ALTERNATOR OUTPUT AT THE PCM
1. Turn the ignition off.
2. Using a voltmeter, back probe and measure the voltage on the (A801) Fused B+ circuit at the PCM C1 harness connector.
3. Start the engine.
4. Hold the engine speed above 1157 rpm.
5. With the scan tool, navigate to data display and monitor the target charging voltage.
  Is the (A801) Fused B+ circuit voltage more than 1.0 volt below the target charging voltage?
  
  Yes
  - Use the wiring diagram/schematic as a guide and inspect the fuses in the PDC or fusible link in the charge wire depending on application. If an open fusible link or fuse is found, perform repair and retest for DTC. If no problems were found, repair the (A801) Fused B+ circuit for excessive resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 7
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 .