Description:

The error code, ATC 001547.03, is triggered when the control unit measures a voltage exceeding 5 volts at the signal input for the evaporator core temperature sensor (B129, lead 2018). This unusually high voltage suggests that the circuit is either shorted to a supply lead or is open, which can lead to incorrect temperature readings and potentially improper operation of the HVAC system.

Reaction:

The high voltage condition could cause the HVAC system to misinterpret the temperature of the evaporator core, potentially leading to overcooling or insufficient cooling. This mismanagement can affect cabin comfort and HVAC system efficiency.

Recommendations:

• Inspect Wiring and Connections: Check the wiring and connections at lead 2018 for signs of damage, wear, or improper contacts that might lead to a short to power supply or an open circuit.
• Measure Voltage Levels: Use a multimeter to verify the voltage at the sensor’s signal input. Continuously high readings confirm the presence of an electrical fault.
• Identify and Repair Circuit Issues: Locate and repair any shorts to power or open connections within the circuit. Replace damaged wires or connectors as needed.
• Test Sensor Functionality: After repairs, test the evaporator core temperature sensor to ensure it accurately measures and reports temperatures.
• Reset System and Verify Operation: Clear any stored fault codes and test the entire HVAC system to ensure it operates correctly under normal conditions, with stable and appropriate responses to temperature changes.

Note:

Regular maintenance of HVAC sensors and their circuits is essential to ensure accurate monitoring and control of system operations. Early detection and correction of voltage irregularities are crucial to maintaining the performance and efficiency of the climate control systems, thereby enhancing the comfort and safety of the vehicle’s occupants.