VW Cabrio 1999 OBD Codes P0121 and P1544: AC Not Working, Temperature Light Flashes

Model: VW Cabrio Fault Code: P0121 Posted: 2008-02-06 20:04

Hi everyone, I own a 1999 VW Cabrio and am experiencing some serious issues after leaving my car lights on for an entire day. This caused the battery to die completely. After replacing the battery, I noticed that the air conditioning has stopped working entirely. Additionally, the check-temperature light is flashing continuously, even though the dashboard thermometer shows normal engine temperature. I used an Actron OBD2 diagnostic tool to read the fault codes, which are: - P0121: Throttle Position Sensor (TPS) / Pedal Position Sensor A - Circuit Range/Performance - P1544: Manufacturer Control Vehicle Speed Idle Speed Control Auxiliary Inputs I'm concerned because summer is approaching in Arizona and temperatures will be extremely high. The AC is essential for driving safely in such heat. I need to understand what these codes mean and how to fix them before the hot weather arrives. Any advice or troubleshooting steps would be greatly appreciated. Thank you!