Examination
1. The MAP sensor monitors variations in the depth of vacuum in the intake manifold associated with changes in crankshaft speed and current engine load, and converts the information received into an amplitude signal. The PCM uses information from the MAP sensor to correct ignition timing settings. The amplitude of the signal generated by the sensor can vary from 1.0 ÷ 1.5 V with a fully closed throttle (deep rarefaction) up to 4.0÷4.5 V at fully open damper (weak vacuum) and may vary slightly depending on vehicle height above sea level. The MAP sensor is mounted on the throttle body, its failures lead to the entry of a fault code P0107 or P0108 into the memory of the self-diagnosis system.
2. Measure the reference voltage applied to the sensor from the PCM. Disconnect the wiring connector and connect a voltmeter between the REF terminals (+) and GND (-) connector. With the ignition on, the device should register a reading of about 5.0 V. The absence of a reference signal indicates an open in the PCM circuit or a failure of the module itself.
3. Check the signal voltage of the sensor with the engine off, connect a voltmeter between the SIG terminals (+) and GND (-) sensor connector. With the ignition on, the signal amplitude should lie within the range of 2.5÷3.5 V.
4. Now you should check the correct operation of the sensor when the power unit is running. Start the engine and observe the voltmeter reading as the engine speed increases from idle. The signal amplitude should increase as the rarefaction depth decreases. At idle, the rarefaction depth is maximum and the signal voltage should not rise above 0.5÷1.5 V. as the speed increases, the rarefaction depth drops, which should lead to a decrease in the amplitude of the measured signal.
Note. The change in the depth of depression in the intake manifold can be traced using a vacuum gauge. With a fully open damper, the pressure in the pipeline can be compared with atmospheric pressure. For more information on vacuum testing, see Part General and overhaul of the engine Head Engine.
5. At negative results of check replace the gauge.
Replacement
1. Disconnect the negative cable from the battery.
Attention! If the stereo system installed in the car is equipped with a security code, before disconnecting the battery, make sure that you have the correct combination to activate the audio system!
2. Disconnect the electrical wiring from the MAP sensor.
3. Turn out fixing screws and remove the gauge from the throttle case.
4. Installation is carried out in the reverse order.