Diagnostic Test

WARNING: This page is about a different car, the 2016 Jeep Wrangler and 2015 Jeep Wrangler. However, it is still accessible from the selected car via links, so may be relevant.

VISUALLY INSPECT THE ALTERNATOR AND BELT
NOTE:
Inspect and test the Battery with the Midtronics Battery Tester or equivalent for a shorted or dead cell before continuing with this test.

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

NOTE:
If the P0622 DTC is also present, diagnose and repair that DTC before continuing with this test procedure.

NOTE:
Inspect the fusible link in the charge wire or fuses in the PDC depending on application. If an open fusible link or fuse is found, use the wire diagram/schematic as a guide and inspect the wiring and connectors for damage.
1. Turn the ignition off.
2. Inspect the Alternator belt and Tensioner for proper size and operation.
3. Check for proper belt routing installation.
  Are the belt and Tensioner installed properly and functioning correctly?
  
  Yes
  - Go To 2
  No
  - Perform the appropriate repair.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to .
CHECK THE ALTERNATOR OUTPUT AT THE ALTERNATOR OUTPUT STUD
1. Start the engine.
2. Hold the engine speed above 1157 rpm.
3. With the scan tool, navigate to data display and monitor the target charging voltage.
4. Using a voltmeter, measure the voltage at the Alternator output stud.
  Is the Alternator output more than 1.0 volt below the target charging voltage?
  
  Yes
  - Verify that there is good pin to terminal contact in the Alternator connector. If OK, replace the Alternator. Refer to GENERATOR , REMOVAL .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to .
  No
  - Go To 3
CHECK THE ALTERNATOR OUTPUT AT THE PCM
1. Turn the ignition off.
2. Disconnect the PCM C1 harness connector.
  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.
3. Connect the (special tool #10436, Adapter, GPEC Diagnostic)in line with the PCM C1 harness connector.
4. Start the engine.
5. Hold the engine speed above 1157 rpm.
6. With the scan tool, navigate to data display and monitor the target charging voltage.
7. Using a voltmeter, measure the voltage between ground and the (A209) Fused B+ circuit at the GPEC Adaptor.
  Is the (A209) Fused B+ circuit voltage more than 1.0 volt below the target charging voltage?
  
  Yes
  - Repair the (A209) Fused B+ circuit for excessive resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to .
  No
  - Go To 4
POWERTRAIN CONTROL MODULE (PCM)
1. Perform the CHECKING THE PCM POWERS AND GROUNDS test procedure. Refer to DIAGNOSIS AND TESTING .
2. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Alternator and the Powertrain Control Module (PCM).
3. Look for any chafed, pierced, pinched, or partially broken wires.
4. Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the Alternator and the Powertrain Control Module connectors.
5. Perform any Service Bulletins that may apply.
  Were there any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to .
  No
  - If the PCM powers and grounds test good, replace and program the Powertrain Control Module (PCM) in accordance with the Service Information. Refer to MODULE, POWERTRAIN CONTROL [EHD,ERB] , REMOVAL MODULE, POWERTRAIN CONTROL, 2.8L DIESEL [ENS] , REMOVAL .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to .