GMC C-Series 2001, Owner'S Manual, Page: 116 / 324

2-72
This light should come on when the ignition is on, but
the engine is not running, as a check to show you it is
working. If it does not come on at all, have it repaired.
NOTICE:
If you keep driving your vehicle with this light
on, after a while, your emission controls may not
work as well, your fuel economy may not be as
good and your engine may not run as smoothly.
This could lead to costly repairs that may not be
covered by your warranty.
Engine Oil Pressure Gage
Gasoline Engine Diesel Engine
The engine oil pressure gage, on the lower right portion
of your instrument panel cluster, shows engine oil
pressure in psi (pounds per square inch) or in kPa
(kilopascals). Oil pressure may vary with outside
temperature and oil viscosity, but readings of 30 to
40 psi (205 to 275 kPa) on gasoline engines at operating
temperature and moderate road speeds are normal. If
you have a diesel engine, the normal operating range
should be between 35 and 70 psi (240 to 480 kPa).