Viper V10-488 8.0L (1992)
Malfunction Indicator Lamp: Description and Operation
FUNCTION
The Malfunction Indicator Lamp is used to indicate immediate service of the engine control system is required. The lamp will illuminate when the PCM
detects an open or shorted circuit, absence of current flow in an output device, or if the oxygen sensors are not switching.
OPERATION
The Malfunction Indicator Lamp illuminates when the ignition key is turned to the ON position and stays lit for 3 seconds as a bulb test.
When the lamp is illuminates it indicates the PCM has entered limp in mode. When in limp in mode, the PCM substitutes a failed input value with a
reading from another functioning input.
Signals that can set Malfunction Indicator Lamp are battery voltage input, charging system, manifold Absolute Pressure sensor (MAP), throttle Position
Sensor (TPS), coolant temperature sensor.
The Malfunction Indicator Lamp can also be used to display fault codes that have been stored in the PCM memory due to a system failure. To display
codes with the Malfunction Indicator Lamp, see Powertrain Management/Computers and Control Systems/Testing and Inspection/Procedures.
