Diagnostic Test

WARNING: This page is about a different car, the 2015 Fiat 500. However, it is still accessible from the selected car via links, so may be relevant.

GENERATOR FULL FIELD TEST
NOTE:
Diagnose and repair any Generator sense or Generator field control circuit DTCs before proceeding with this test.
1. Start the engine and allow it to idle.
  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 can result in personal injury or death.
2. With the scan tool, perform the Generator Full Field test. Follow the instructions displayed on the scan tool.
3. Monitor the system (battery) voltage and the Generator sense voltage on the scan tool while performing the test.
  NOTE:
  With the engine running, the difference between the system (battery) voltage and the Generator sense voltage should be below 0.2 volts.
  
  NOTE:
  With the generator field fully actuated, the system (battery) voltage should be above 14.0 volts.
  
  NOTE:
  With the generator field actuated off, the system (battery) voltage should be below 13.0 volts and eventually drop as battery load is increased.
  
  Did the system voltage change as described above during the Generator Full Field test?
  
  Yes
  - Test complete.
  No
  - Go To 2
CHARGING SYSTEM INSPECTION
1. Turn the ignition off.
2. Inspect and load test the battery in accordance with the Service Information.
3. Inspect the Generator drive belt for proper alignment and adjustment.
4. Inspect the vehicle for aftermarket accessories that may exceed the generator system output.
5. Inspect the fuses. If an open fuse is found, use the wire diagram/schematics as a guide and inspect the wiring and connectors for a damaged or shorted circuit.
  Were any problems found?
  
  Yes
  - Repair as necessary.
  No
  - Go To 3
GENERATOR OUTPUT CIRCUIT HIGH RESISTANCE
NOTE:
Make sure all testing equipment and cables are clear of any engine parts before starting the engine.
1. Start the engine.
  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 can result in possible serious or fatal injury.
2. Measure the voltage between the B (+) Terminal at the Generator and the Battery Positive (+) Post.
  Is the voltage below 0.1 volts?
  
  Yes
  - Go To 4
  No
  - Repair the Generator Output circuit between the Generator and battery for high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to the appropriate Diagnostics & Testing article in Engine Performance. For 16V, refer to POWERTRAIN VERIFICATION TEST, 16V . For 16V Turbo, refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
GENERATOR CASE GROUND HIGH RESISTANCE
1. Measure the voltage between the Generator case and the Battery Negative (-) post.
  Is the voltage below 0.1 volts?
  
  Yes
  - Go To 5
  No
  - Repair the Generator Case ground for high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to the appropriate Diagnostics & Testing article in Engine Performance. For 16V, refer to POWERTRAIN VERIFICATION TEST, 16V . For 16V Turbo, refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
GENERATOR
1. Turn the ignition off.
2. Disconnect the Generator harness connector.
3. Connect a 12-volt test light between ground and the (K125) Generator Field Control circuit in the Generator harness connector.
4. Turn the ignition on.
5. With the scan tool, actuate the Alternator Field Control State to toggle.
  NOTE:
  The test light should toggle on and off with the actuation.
  
  NOTE:
  If a DTC is active, the actuation test may not be allowed by the PCM. If may be necessary to clear DTCs before starting the actuation.
  
  Does the test light illuminate on and off with the actuation?
  
  Yes
  - Replace the Generator in accordance with the service information.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to the appropriate Diagnostics & Testing article in Engine Performance. For 16V, refer to POWERTRAIN VERIFICATION TEST, 16V . For 16V Turbo, refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
  No
  - Go To 6
(K125) GENERATOR FIELD CONTROL CIRCUIT SHORTED TO VOLTAGE
1. Turn the ignition off.
2. Disconnect the PCM C2 harness connector.
3. Turn the ignition on.
4. Measure the voltage of the (K125) Generator Field Control circuit in the Generator harness connector.
  Is there any voltage present?
  
  Yes
  - Repair the (K125) Generator Field Control circuit for a short to voltage.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to the appropriate Diagnostics & Testing article in Engine Performance. For 16V, refer to POWERTRAIN VERIFICATION TEST, 16V . For 16V Turbo, refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
  No
  - Go To 7
(K125) GENERATOR FIELD CONTROL CIRCUIT SHORTED TO GROUND
1. Turn the ignition off.
2. Measure the resistance between ground and the (K125) Generator Field Control circuit in the Generator harness connector.
  Is the resistance above 10k Ohms?
  
  Yes
  - Go To 8
  No
  - Repair the (K125) Generator Field Control circuit for a short to ground.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to the appropriate Diagnostics & Testing article in Engine Performance. For 16V, refer to POWERTRAIN VERIFICATION TEST, 16V . For 16V Turbo, refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
(K125) GENERATOR FIELD CONTROL CIRCUIT OPEN OR HIGH RESISTANCE
1. Measure the resistance of the (K125) Generator Field Control circuit between the Generator harness connector and the appropriate terminal of PCM C2 harness connector.
  Is the resistance below 5.0 Ohms?
  
  Yes
  - Go To 9
  No
  - Repair the (K125) Generator Field Control circuit for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to the appropriate Diagnostics & Testing article in Engine Performance. For 16V, refer to POWERTRAIN VERIFICATION TEST, 16V . For 16V Turbo, refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
CHECKING THE PCM POWER AND GROUND CIRCUITS
1. Perform the CHECKING THE PCM POWER AND GROUND CIRCUIT test procedure. Refer to CHECKING THE PCM POWER AND GROUND CIRCUITS .
  Were any problems found?
  
  Yes
  - Repair as necessary in accordance with the service information.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to the appropriate Diagnostics & Testing article in Engine Performance. For 16V, refer to POWERTRAIN VERIFICATION TEST, 16V . For 16V Turbo, refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
  No
  - Go To 10
POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Generator 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. Perform any Technical Service Bulletins that may apply.
  Were any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to the appropriate Diagnostics & Testing article in Engine Performance. For 16V, refer to POWERTRAIN VERIFICATION TEST, 16V . For 16V Turbo, refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
  No
  - Replace and program the Powertrain Control Module (PCM) in accordance with the service information. Refer to MODULE, POWERTRAIN CONTROL, REMOVAL .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to the appropriate Diagnostics & Testing article in Engine Performance. For 16V, refer to POWERTRAIN VERIFICATION TEST, 16V . For 16V Turbo, refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .