Cadillac CTS 2003 Owner's Manual

To reset the oil life monitor, turn the ignition to the ON position without starting the engine. Press the "INFO" button on the Driver Information Center until "Oil Life" is displayed. Press and hold the "RESET" button until the display reads "100%." Release the button to complete the reset.
The 2003 Cadillac CTS typically requires 5W-30 engine oil that meets GM Standard GM6094M. Always consult the owner's manual for the most accurate information.
To replace the headlight bulb, open the hood and locate the back of the headlight assembly. Remove the electrical connector and the dust cover. Twist and remove the bulb, then replace it with a new one. Reconnect the electrical connector and replace the dust cover.
Start by checking the refrigerant level; low levels can impede cooling. Examine the AC compressor and relay for proper operation. Ensure the cabin air filter is not clogged. If these steps don't resolve the issue, a professional diagnosis may be necessary.
Regular maintenance includes oil changes every 3,000-5,000 miles, checking tire pressure monthly, rotating tires every 7,500 miles, and replacing the air filter every 15,000 miles. Always refer to the owner's manual for detailed maintenance schedules.
Insert the original key into the ignition and turn it to the ON position. Remove the original key and insert the new key within 5 seconds. Turn the new key to the ON position and wait for the security light to turn off, indicating programming is complete.
Common issues may include rough shifting or slipping. Regularly check and maintain transmission fluid levels. If issues persist, a transmission flush or inspection by a professional mechanic may be required.
To replace the battery, open the hood and locate the battery. Disconnect the negative cable followed by the positive cable. Remove the battery hold-down bracket and lift the battery out. Place the new battery in the tray, secure it, and reconnect the cables, positive first, then negative.
To improve fuel efficiency, ensure regular maintenance such as timely oil changes and air filter replacements. Maintain proper tire pressure, avoid carrying unnecessary weight, and drive smoothly, avoiding rapid acceleration and braking.
To fix a leaking sunroof, first check the sunroof drains for clogs. Clean the drains with compressed air or a flexible rod. Inspect the sunroof seal for damage and replace it if necessary. If leaks persist, professional inspection may be required.