WOMS
P code powertrain Medium severity

P1245 Alternator Load Input Failed Low

The OBD2 code P1245 indicates that the alternator load input signal is reading lower than expected, which may suggest a problem with the alternator, wiring, or the engine control module's ability to interpret the signal

Definition

The OBD2 code P1245 indicates that the alternator load input signal is reading lower than expected, which may suggest a problem with the alternator, wiring, or the engine control module's ability to interpret the signal

Common causes

  • Faulty alternator
  • Bad alternator wiring or connections
  • Failed alternator load input sensor
  • Damaged or corroded connectors
  • Faulty engine control module (ECM)
  • Low battery voltage
  • Faulty or weak battery

Common misdiagnoses

  • Faulty alternator
  • Bad battery
  • Wiring issues
  • Faulty voltage regulator
  • Engine control module (ECM) problems
  • Ground connection issues
  • Sensor malfunctions
  • Corroded connectors

Troubleshooting steps

  1. 1. Check the Battery Voltage:

    Ensure the battery is fully charged and in good condition. A weak or dead battery can cause various electrical issues

  2. 2. Inspect the Alternator:

    Check the alternator for any physical damage or signs of wear

  3. 3. Ensure that the alternator belt is in good condition and properly tensioned

  4. 4. Test the Alternator Output:

    Use a multimeter to measure the voltage output of the alternator. It should typically be between 13.5 to 14.5 volts when the engine is running

  5. 5. If the output is low, the alternator may need to be replaced

  6. 6. Check Wiring and Connectors:

    Inspect the wiring and connectors between the alternator and the ECM for any signs of damage, corrosion, or loose connections

  7. 7. Pay special attention to the alternator load input wire

  8. 8. Scan for Additional Codes:

    Use an OBD-II scanner to check for any other related trouble codes that may provide more context to the issue

  9. 9. Test the ECM:

    If all other components are functioning correctly, the issue may lie with the ECM itself. Check for any software updates or reprogramming that may be needed

  10. 10. Check for Ground Issues:

    Ensure that the alternator and ECM have a good ground connection. Poor grounding can lead to erroneous readings

  11. 11. Inspect Fuses and Relays:

    Check the fuses and relays associated with the charging system to ensure they are functioning properly

  12. 12. Perform a Load Test:

    Conduct a load test on the battery and alternator to ensure they can handle the electrical load of the vehicle

  13. 13. Consult Repair Manual

  14. 14. Refer to the vehicle's repair manual for specific troubleshooting steps and specifications related to the alternator and ECM. If after performing these steps the issue persists, it may be advisable to consult a professional mechanic for further diagnosis and repair