Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2003 Cadillac CTS AutomaticFACTORY OEM SERVICE PROCEDURE
HVAC, Automatic DTCS
HVAC - AUTOMATIC DIAGNOSTIC TROUBLE CODE (DTC) LIST
| DTC | Description |
|---|---|
| DTC B0126, B0409, or B0419 | Actual Door Position Differs From The Commanded Door Position |
| DTC B0130, B0414, or B0424 | Door Position Signal Circuit |
| DTC B0160 or B0162 | Ambient Air Temperature Sensor Signal Circuit |
| DTC B0164 | Inside Air Temperature Sensor Signal Circuit |
| DTC B0184 or B0189 | Sunload Sensor |
| DTC P0532 or P0533 | A/C Refrigerant Pressure Sensor Signal Voltage |
| DTC P0645, P0646, or P0647 | A/C Compressor Clutch Relay Control Circuit |
| DTC P1531 | Evaporator Temperature Sensor Signal Circuit |
Factory Service Tools
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.