Eighty-Eight Royale FWD V6-3.8L VIN K (1996)
Engine Control Module: Description and Operation
PCM Outputs
PCM CONTROLLED WARNING LAMPS
The PCM controlled lamps are intended to alert the driver to an operating condition which may require immediate attention. The instrument panel
indicators, ignition 1 feed, powers the PCM controlled lamps. Low Oil Level Lamp
The PCM commands the Low Oil Level Lamp ON if the engine oil level sensor indicates that a low oil level condition exists. The PCM
determines whether or not to test for low oil level based on the difference between engine coolant temperature at the last shutdown and engine
coolant temperature at start-up. This is to ensure that the oil has drained back into the oil pan before testing.
HOT LAMP
The PCM commands the Hot lamp ON when the engine coolant temperature exceeds 124°C (255°F). The PCM commands the Hot lamp OFF
when the engine coolant temperature falls below 120°C (248°F).
CHANGE OIL LAMP
The PCM commands the Oil Life Monitor lamp ON when an oil change is require. The PCM calculates remaining Oil life based on total engine
revolutions and calculated engine oil temperature for each start-up since the Oil Life monitor was reset.
GENERATOR LAMP
The PCM commands the generator lamp ON under the following conditions:
^
When the engine speed is greater than 1200 RPM and system voltage falls below 10 volts for longer than 10 seconds. The PCM commands
the generator lamp OFF when system voltage rises to above 12 volts.
^
When the generator control circuit (L terminal) remains low for longer than 10 seconds.
^
When the engine speed is below 2000 RPM and the generator PWM control circuit (F terminal) duty cycle falls below 5% and remains
below 15% for longer than 20 seconds.
^
When the engine speed is above 4000 RPM and the generator PWM control circuit (F terminal) duty cycle increases to above 95% and
remains above 85% for longer than 20 seconds.
PCM CONTROLLED AIR CONDITIONING
The air conditioning system uses a compressor with variable displacement. This compressor is referred to as the V-5 type compressor. The V-5
compressor meets A/C requirements without cycling. The A/C compressor operation is controlled by the Powertrain Control Module (PCM).
ELECTRIC COOLING FANS
The electric cooling fans are used to cool engine coolant flowing through the radiator. They are also used to cool the refrigerant (R134a) flowing
through the A/C condenser.
Power for the cooling fan motors is supplied by the Cooling Fans Maxi-Fuse. The relays are energized when the PCM grounds the fan control
driver circuits.
