Dodge 2009 Ram 3500 - Manual (Page 196)

18. Malfunction Indicator Light (MIL)
The Malfunction Indicator Light (MIL) is part of
an onboard diagnostic system, called OBD II, that
monitors engine and automatic transmission con-
trol systems. The light will illuminate when the key is in
the ON position, before engine start. If the bulb does not
come on when turning the key from OFF to ON, have the
condition checked promptly.
Certain conditions such as a loose or missing gas cap,
poor fuel quality, etc., may illuminate the MIL after
engine start. The vehicle should be serviced if the light
stays on through several of your typical driving cycles. In
most situations, the vehicle will drive normally and will
not require towing.
If the MIL flashes when the engine is running, serious
conditions may exist that could lead to immediate loss of
power or severe catalytic converter damage. The vehicle
should be serviced as soon as possible if this occurs.
19. Brake Warning Light
This light monitors various brake functions,
including brake fluid level and parking brake
application. If the brake light turns on, it may
indicate that the parking brake is applied, that
the brake fluid level is low, or that there is a problem with
the anti-lock brake system reservoir.
If the light remains on when the parking brake has been
disengaged, and the fluid level is at the full mark on the
master cylinder reservoir, it indicates a possible brake
hydraulic system malfunction or that a problem with the
Brake Booster has been detected by the Anti-Lock Brake
System (ABS) / Electronic Stability Program (ESP) sys-
tem. In this case, the light will remain on until the
condition has been corrected. If the problem is related to
the brake booster, the ABS pump will run when applying
the brake and a brake pedal pulsation may be felt during
each stop.
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