there is a sequence of buttons pushed on the radio which access the ODB, sorry can't remember the sequence.
You can find it on 12volt.com
what buttons are used to bring up codes on display of 1994 cadillac etc
Reading the codes requires a scan tool.
how do you check a/c codes on a 2000 Cadillac Seville sls
first you have to run you car through a dyno test.
probably something was left unplugged. Go to auto zone and get the codes read for free and it should tell you what it is.
There are pages and pages and items that can cause a check engine light. You need to have it checked for codes with a scan tool. After repair light can be shut off with scan tool.
You cannot adjust the idle in a 1998 Cadillac Catera. It is computer controlled. If the idle is not at 750 rpms then there is another problem with the engine. Check for codes with an OBD2 tester.
press n hold the off and warmer buttons on heater controls while key is on
Hold in the off and warmer buttons on your air conditioning.. and it will throw up error codes on the LCD panel that shows how much gas you have.
push the AC and heater buttons in at the same time and hold for 6 seconds
you check the system for trouble codes.