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Lotus Service Notes Section EMN
Page 9
MN.6 - MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR
The MAP signal is fundamental to the calculation of air consumption and fuel calibration. The ECM
provides a 5 volt supply and earth path to the sensor, which returns a voltage representing the manifold
pressure.
On standard engines, the MAP sensor is contained within the ECM and receives a signal from the intake
plenum ahead of no.1 cylinder intake tract, via a small bore rubber vacuum hose. A liquid trap is incorporated
into this line and is mounted on the right hand side of the engine bay aperture. Faults with the MAP sensor
require that the ECM be replaced.
When using the 'Lotus Check' tool, an atmospheric pressure of approximately 100 KPa should be dis-
played with the engine stopped, and a lower value between 25 - 40 KPa during idle. Very high values may
indicate a faulty sensor, or a blocked or leaking connecting hose. Moderately raised values indicate a possible
engine fault.
On VVC engined cars, the MAP sensor is mounted directly onto the front end of the intake plenum, and
by avoiding the damping effect of a connecting hose, is able to respond more quickly to changes in plenum
pressure. When replacing the sensor, renew the 'O' ring and tighten the two fixing screws to 9 Nm.
Standard cars:
MAP sensor line liquid trap
em201
VVC cars:
MAP sensor
em220
Relay
em197 module em222a