WOMS
B code body Medium severity

B1855 Climate Control Air Temperature Internal Sensor Motor Circuit Short To Battery

The OBD2 code B1855 indicates a short circuit in the climate control air temperature internal sensor motor circuit, causing it to connect directly to the battery voltage

Definition

The OBD2 code B1855 indicates a short circuit in the climate control air temperature internal sensor motor circuit, causing it to connect directly to the battery voltage

Common causes

  • Shorted wiring or connectors
  • Faulty internal temperature sensor
  • Malfunctioning climate control module
  • Damaged or corroded connectors
  • Grounding issues
  • Electrical shorts in the motor circuit

Common misdiagnoses

  • Faulty climate control module
  • Defective internal temperature sensor
  • Wiring issues or shorts in the harness
  • Malfunctioning blower motor
  • Incorrectly calibrated climate control system
  • Issues with the HVAC control panel
  • Battery or charging system problems

Troubleshooting steps

  1. 1. Check the Vehicle's Battery and Charging System

    Ensure the battery is in good condition and fully charged

  2. 2. Check the alternator and charging system for proper operation

  3. 3. Inspect Wiring and Connectors

    Visually inspect the wiring harness and connectors related to the climate control system, especially those connected to the internal temperature sensor and motor

  4. 4. Look for signs of damage, corrosion, fraying, or loose connections

  5. 5. Repair or replace any damaged wiring or connectors

  6. 6. Test the Internal Temperature Sensor

    Locate the internal temperature sensor and test its resistance using a multimeter. Compare the readings to the specifications in the vehicle's service manual

  7. 7. If the sensor is out of specification, replace it

  8. 8. Check the Motor Circuit

    Inspect the motor that controls the air temperature for any signs of damage or malfunction

  9. 9. Test the motor for proper operation by applying direct power to it (if safe to do so) to see if it functions correctly

  10. 10. Scan for Additional Codes

    Use an OBD-II scanner to check for any additional trouble codes that may provide more context or indicate related issues

  11. 11. Address any other codes found, as they may be contributing to the problem

  12. 12. Check for Short Circuits

    Use a multimeter to check for continuity in the wiring harness. Look for any shorts to ground or battery voltage

  13. 13. If a short is found, trace the wiring to locate the source and repair it

  14. 14. Inspect the Climate Control Module

    If all other components check out, the issue may lie within the climate control module itself

  15. 15. Check for any software updates or recalls related to the climate control system

  16. 16. If necessary, consider replacing the climate control module

  17. 17. Clear Codes and Test Drive

    After performing repairs, clear the trouble codes using an OBD-II scanner

  18. 18. Take the vehicle for a test drive to see if the code reappears

  19. 19. Consult a Professional

    If the issue persists after performing these steps, it may be best to consult a professional mechanic or technician who has experience with your specific vehicle make and model.Additional Tips: - Always refer to the vehicle's service manual for specific diagnostic procedures and specifications. - Ensure safety precautions are taken when working with electrical components and systems. By following these troubleshooting steps, you should be able to identify and resolve the issue related to the B1855 code