WOMS
P code powertrain Medium severity

P1535 Blower Fan Speed Circuit Range/Performance

The OBD2 code P1535 indicates a problem with the blower fan speed circuit, specifically that the performance or range of the blower fan speed is outside the expected parameters

Definition

The OBD2 code P1535 indicates a problem with the blower fan speed circuit, specifically that the performance or range of the blower fan speed is outside the expected parameters

Common causes

  • Faulty blower motor
  • Blower motor resistor failure
  • Wiring issues (shorts, opens, or corrosion)
  • Faulty blower motor control module
  • Poor ground connections
  • Malfunctioning HVAC control module
  • Incorrectly set or faulty climate control settings

Common misdiagnoses

  • Faulty blower motor
  • Blower motor resistor failure
  • Wiring issues or shorts in the circuit
  • Faulty HVAC control module
  • Incorrectly calibrated or malfunctioning climate control system
  • Issues with the vehicle's battery or charging system
  • Faulty fuses or relays related to the blower system

Troubleshooting steps

  1. 1. Check for Additional Codes

    Use an OBD-II scanner to check for any other trouble codes that may be present. This can provide more context for the issue

  2. 2. Inspect the Blower Motor

    Visual Inspection: Check the blower motor for any visible damage or obstructions

  3. 3. Functionality Test

    Turn on the vehicle and test the blower motor at different speed settings to see if it operates correctly

  4. 4. Examine the Blower Motor Resistor

    The blower motor resistor controls the speed of the blower motor. Inspect it for any signs of damage or corrosion

  5. 5. Test the resistor with a multimeter to ensure it is functioning within specifications

  6. 6. Check Wiring and Connectors

    Inspect the wiring and connectors related to the blower motor and resistor for any signs of wear, corrosion, or loose connections

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

  8. 8. Test the Blower Motor Relay

    If your vehicle has a relay for the blower motor, test it to ensure it is functioning properly. Swap it with a similar relay if necessary to see if that resolves the issue

  9. 9. Check the Control Module

    If the blower motor and resistor are functioning correctly, the issue may lie with the HVAC control module. Check for any software updates or faults in the module

  10. 10. Inspect the Ground Connections

    Ensure that all ground connections related to the blower motor circuit are clean and secure. Poor ground connections can lead to performance issues

  11. 11. Perform a Voltage Drop Test

    Use a multimeter to perform a voltage drop test on the blower motor circuit to ensure that the motor is receiving the correct voltage

  12. 12. Clear Codes and Test Drive

    After performing repairs, clear the trouble codes and take the vehicle for a test drive to see if the code reappears

  13. 13. Consult a Professional

    If the issue persists after performing these steps, it may be necessary to consult a professional mechanic for further diagnosis. By following these troubleshooting steps, you should be able to identify and resolve the issue related to the P1535 code. Always refer to the vehicle's service manual for specific procedures and specifications