ENGINE MANAGEMENT SYSTEM
SENSOR - MANIFOLD ABSOLUTE PRESSURE
(MAP) / INLET AIR TEMPERATURE (IAT)
The MAP/IAT sensors are combined in one unit located in the inlet manifold. It provides pressure and temperature
information about the air in the inlet manifold to the ECM. The ECM compares the voltage signal to stored values
and compensates fuel delivery as necessary. The ECM uses the signal from the MAP/IAT sensor for the following
functions:
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To calculate the delivered fuel limits.
To calculate the air mass in the cylinder.
To calculate the air speed density.
To calculate the air temperature.
The MAP sensor works on the piezo crystal principal. Piezo crystals are pressure sensitive and will oscillate in
accordance to changes in air pressure. The MAP sensor produces a voltage between 0 and 5 volts proportional to
the pressure level of the air in the inlet manifold. A reading of 0 volts indicates a low pressure, a reading of 5 volts
a high pressure.
The IAT portion of the sensor works as a Negative Temperature Co-efficient (NTC) sensor. As air temperature
rises, the resistance in the sensor decreases. As temperature decreases the resistance in the sensor increases.
The ECM compares the voltage signal to stored values and compensates fuel delivery as necessary.
Inputs / Outputs
The MAP/IAT sensor (C0567-3) is provided a 5 volt supply by the ECM (C0158-8) on a pink/purple wire. The
MAP/IAT sensor provides the ECM with 2 outputs. The MAP sensor output (C0567-4) is connected to the ECM
(C0158-6) by a white/yellow wire. The IAT sensor output (C0567-2) is connected to the ECM (C0158-34) on a
green/black wire. The MAP/IAT sensor is earthed (C0567-1) via the ECM (C0158-17) on a pink/black wire.
DESCRIPTION AND OPERATION
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| Categories | Land Rover, Land Rover Defender |
|---|---|
| Tags | Land Rover |
| Model Year | 1999, 2000, 2001, 2002 |
| Download File |
|
| Document Type | Workshop Manual |
| Language | English |
| Product Name | Defender |
| Product Brand | Land Rover |
| Document File Type | |
| Publisher | landrover.com |
| Wikipedia's Page | http://en.wikipedia.org/wiki/Land_Rover |
| Copyright | Attribution Non-commercial |
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