4. Fuel Injection System
4-17
MAP Sensor
Working voltage
measurement
Output voltage measurement
plains
Functional Description:
● Powered by 5V DC from ECU. It has 3-pin socket on the sensor. One
terminal is for power, and 1 terminal are for signal output. And, the
rest one is for ground.
● The major component of the intake pressure sensor is a variable
transistor IC. Its reference voltage is DC 5V, and output voltage range
is DC 0~5V.
● It is a sensor by sensing pressure, and can measure the absolute
pressure in intake process. It also conducts fuel injection quantity
correction based on environmental position level.
Pin Wire color Function
Left Yellor / Black 5V voltage input
center Black / Red Signal output
Right Green / Red Ground
Testing Procedures:
1. Inlet pressure sensor connector to properly (using the probe tool).
2. Open the main switch, but not to start engine.
3. Use "volteg meter" DC stalls (DCV) to check inlet pressure sensor
voltage.
4. Confirmed working voltage:
● Volteg meter negative access to the inlet pressure sensor third pin
(Green / Red).
● Voltage meter positive access to the inlet pressure sensor first pin
(Yellow / Black).
5. Confirmed plains output voltage values:
● Volteg meter negative access to the inlet pressure sensor third pin
(Green / Red).
● Voltage meter positive access to the inlet pressure sensor second
pin (Black / Red)
Cautions
● Attentions to the tools required close to the probe wire waterproof
apron penetrate skin and internal terminal before measurements to
the correct value.
Detection judge:
● Working voltage value: 5.0±0.1V
● Plains output voltage values: 2.87±0.03V (Conditions: In the plains
101.3 kPa Measurement)
Cautions
● The higher the altitude, the measurement value to the lower voltage.
● Sea-level atmospheric pressure = 1Atm = 101.3kPa = 760mmHg =
1013mbar
Treatment of abnormal phenomena:
● Inlet pressure sensor damaged, or poor contact couplers.
● Check whether the abnormal wire harness lines.
● Inlet pressure sensor anomaly, the proposed replacement of the
sensor to measure the output voltage.
● ECU anomaly, the proposed replacement of the ECU to measure the
working voltage.
Y/B B/R
G/R
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