GMC C-Series 2001 Owner's Manual page 117

A reading in the low pressure zone may be caused by a
dangerously low oil level or other problem.
R
If you have a Caterpillar
R
Caterpillar Operation & Maintenance Manual.
CAUTION:
Don't keep driving if the oil pressure is low.
If you do, your engine can become so hot that it
catches fire. You or others could be burned.
Check your oil as soon as possible and have your
vehicle serviced.
NOTICE:
Damage to your engine from neglected oil
problems can be costly and is not covered by
your warranty.
diesel engine, also see your
Change Oil Light (If Equipped)
If the CHANGE OIL light comes on and stays on after
you start the engine, have the oil changed.
For additional information, see "Engine Oil, When to
Change" in the Index. To reset the Oil Life Monitor, see
"Engine Oil Life Monitor" in the Index.
The CHANGE OIL light
should come on briefly
as a bulb check when you
start the engine. If the
light doesn't come on,
have it serviced.
2-73