Air Management
The EMS2000 sees engine cranking through the crank sensor. It checks the PWG and should see .5 volts on both inputs indicating request for idle. The feedback potentiometers are checked in the EDR to confirm throttle plate position. Signals of 0.5 volts from Pot 1 and 4.5 volts from Pot 2 indicate the throttle plate is in the LL or idle position.
With the engine now cranking the EMS2000 looks at inputs from the TMAP (and Map, if a COOPER S). TMAP volts drops from 4 volts toward the high vacuum voltage reading of 1 volt. A voltage of 5 volts or 0 volts puts the EMS2000 in Fault Mode. A fault is registered and air volume information is derived from a default map.
Intake air temperature is checked, 4 volts indicating a cold air, 1 volt or less hot air.
From the TMAP and Intake air temperature the intake air volume and density is calculated.