GMC Cadillac CTS 2004 Owner's Manual page 316

When the system has calculated that oil life has been
diminished, it will indicate that an oil change is
necessary. A Change Engine Oil message in the DIC
will come on. Change your oil as soon as possible within
the next two times you stop for fuel. It is possible that,
if you are driving under the best conditions, the oil
life system may not indicate that an oil change is
necessary for over a year. However, your engine oil and
filter must be changed at least once a year and at
this time the system must be reset. Your dealer has
GM-trained service people who will perform this
work using genuine GM parts and reset the system. It is
also important to check your oil regularly and keep it
at the proper level.
If the system is ever reset accidentally, you must
change your oil at 3,000 miles (5 000 km) since your
last oil change. Remember to reset the oil life system
whenever the oil is changed.
How to Reset the Change Engine Oil
Message and the Oil Life Indicator
The GM Oil Life System calculates when to change
your engine oil and filter based on vehicle use.
Anytime your oil is changed, reset the system so it can
calculate when the next oil change is required. If a
situation occurs where you change your oil prior to a
Change Engine Oil Message in the DIC being turned on,
reset the system.
5-22
After the oil has been changed, the Change Engine Oil
message and the oil life indicator must be reset.
To reset the message and indicator, use one of the
following procedures:
Base Audio System
Press the CLR button located to the right of the DIC
display to acknowledge the Change Engine Oil
message. This will clear the message from the display
and reset it.
To reset the oil life indicator, use the following steps:
1. Press the up or down arrow on the INFO button
located to the right of the DIC display to access
the DIC menu.
2. Once XXX% ENGINE OIL LIFE menu item is
highlighted, press and hold the CLR button.
The percentage will return to 100, and the oil life
indicator will be reset. Repeat the steps if the
percentage does not return to 100.
3. Turn the key to OFF.
If the Change Engine Oil message comes back on
when you start your vehicle, the engine oil life system
has not reset. Repeat the procedure.