WOMS
B code body Medium severity

B1252 Air Temperature Internal Sensor Circuit Short To Battery

The OBD2 code B1252 indicates a short circuit in the air temperature internal sensor circuit, causing it to connect directly to the battery voltage, which can lead to incorrect readings or sensor failure

Definition

The OBD2 code B1252 indicates a short circuit in the air temperature internal sensor circuit, causing it to connect directly to the battery voltage, which can lead to incorrect readings or sensor failure

Common causes

  • Shorted wiring or connectors
  • Faulty air temperature sensor
  • Corroded or damaged electrical connections
  • Malfunctioning engine control module (ECM)
  • Improper installation or replacement of the sensor
  • Grounding issues in the circuit

Common misdiagnoses

  • Faulty air temperature sensor
  • Wiring issues or shorts in the harness
  • Faulty engine control module (ECM)
  • Incorrectly installed or damaged connectors
  • Issues with the climate control module
  • Faulty ambient temperature sensor
  • Problems with the vehicle's battery or charging system

Troubleshooting steps

  1. 1. Check the Vehicle's Manual

    Refer to the vehicle's service manual for specific information regarding the air temperature sensor and its circuit

  2. 2. Visual Inspection

    Wiring and Connectors: Inspect the wiring harness and connectors associated with the air temperature sensor for any signs of damage, corrosion, or loose connections

  3. 3. Sensor Condition

    Check the air temperature sensor itself for physical damage or contamination

  4. 4. Test the Sensor

    Resistance Check: Use a multimeter to measure the resistance of the air temperature sensor. Compare the readings to the specifications in the service manual

  5. 5. Voltage Check

    With the ignition on (engine off), check the voltage at the sensor connector. It should match the expected voltage as per the specifications

  6. 6. Check for Short Circuits

    Continuity Test: Perform a continuity test on the wiring to check for shorts to battery voltage. Disconnect the sensor and check for continuity between the sensor wire and the battery positive terminal

  7. 7. Ground Check

    Ensure that the ground connection for the sensor is intact and not shorted to battery voltage

  8. 8. Scan for Additional Codes

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

  9. 9. Inspect Related Components

    Check other components that may be related to the air temperature sensor circuit, such as the Engine Control Module (ECM) or any associated relays and fuses

  10. 10. Clear the Code

    After performing the checks and repairs, clear the trouble code using an OBD-II scanner and take the vehicle for a test drive to see if the code reappears

  11. 11. Professional Diagnosis

    If the issue persists after performing the above steps, consider seeking help from a professional mechanic or technician who can perform more advanced diagnostics

  12. 12. Replace the Sensor (if necessary)

    If the sensor is found to be faulty during testing, replace it with a new one and recheck the system

  13. 13. Monitor the System

    After repairs, monitor the vehicle's performance and check for any recurring codes to ensure the issue has been resolved. By following these steps, you should be able to identify and address the cause of the B1252 code effectively