Checking the condition and replacing the absolute pressure sensor in the pipeline (MAP) (Honda Accord 6)

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 received information into an amplitude signal. The PCM uses the information received from the MAP sensor when adjusting the ignition timing settings. The amplitude of the signal generated by the sensor can vary from 1.0÷1.5 V with the throttle valve fully closed (deep vacuum) to 4.0÷4.5 V with the throttle valve fully open (weak vacuum) and can vary slightly depending on the vehicle altitude above sea level. The MAP sensor is attached to the throttle body, its failures lead to the recording of the P0107 or P0108 fault code in the self-diagnostic system memory.

2. Measure the reference voltage supplied to the sensor from the PCM. Disconnect the wiring connector and connect a voltmeter between the REF (+) and GND (-) terminals of the 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 circuit in the PCM circuit or failure of the module itself.

3. Check the signal voltage of the sensor with the engine off, connect a voltmeter between the terminals SIG (+) and GND (-) of the sensor connector. With the ignition on, the signal amplitude should be within the range of 2.5÷3.5 V.

4. Now you should check the sensor operation with the power unit running. Start the engine and observe the voltmeter readings as the engine speed increases from idle. The signal amplitude should increase as the vacuum depth decreases. At idle, the vacuum depth is maximum and the signal voltage should not rise above 0.5÷1.5 V. As the speed increases, the vacuum depth decreases, which should lead to a decrease in the amplitude of the measured signal.

Note: The change in the depth of vacuum in the intake manifold can be monitored using a vacuum gauge. With the valve fully open, the pressure in the manifold can be compared with atmospheric pressure. More detailed information on vacuum tests is given in Section General and major engine repairs Chapters Engine.

5. If the test results are negative, replace the sensor.

Replacement

1. Disconnect the negative cable from the battery.

Warning! If the car stereo system is equipped with a security code, make sure you have the correct combination to activate the audio system before disconnecting the battery!