GMC 1993 Jimmy Owner's Manual page 137

Malfunction Indicator
Lamp (Senrice €nghe Soon)
Standard Cluster Digital Cluster
PO161
A computer monitors operation of your fuel, ignition and emission control
systems. 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
ail, have it fixed right away. If
it
stays on, or comes on while you are driving,
the computer is indicating that you have a problem. You should take your
vehicle in for service soon.
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