Ram Trucks 2015 ProMaster Commercial - Diesel Supplement - Manual (Page 22)

The light also will turn on when the parking brake is
applied with the ignition switch in the ON/RUN position.
NOTE:
This light shows only that the parking brake is
applied. It does not show the degree of brake application.
16. Malfunction Indicator Light (MIL)
The Malfunction Indicator Light (MIL) is part
of an Onboard Diagnostic (OBD) system which
monitors the emissions and engine control sys-
tem. If the bulb does not come on during
starting, have the condition investigated promptly.
If this light comes on and remains on while driving, it
suggests a potential engine control problem and the need
for system service.
Although your vehicle will usually be drivable and not
need towing, see your authorized dealer for service as
soon as possible.
CAUTION!
Prolonged driving with the Malfunction Indicator
Light (MIL) on could cause damage to the engine
control system. It also could affect fuel economy and
driveability. If the MIL is flashing, severe catalytic
converter damage and power loss will soon occur.
Immediate service is required.
17. Temperature Gauge
The temperature gauge shows engine coolant tempera-
ture. Any reading within the normal range indicates that
the engine cooling system is operating satisfactorily.
The gauge pointer will likely indicate a higher tempera-
ture when driving in hot weather, up mountain grades,
or when towing a trailer. It should not be allowed to
exceed the upper limits of the normal operating range.
20 UNDERSTANDING YOUR INSTRUMENT PANEL