Cartwaveforms > sensors > map sensor > MAP Sensor (Digital)
Download this waveform file | This is a good waveform |
|---|
MAP Sensor (Digital) Waveform Notes
The Manifold Absolute Pressure (MAP) sensor is employed to measure the vacuum in the inlet manifold.
It is this output that when sent back to the engine management system can determine either the fueling or the amount of vacuum (or light load) advance.
The sensor is a three wire device which will have a:
- A 5 volt supply voltage
- An earth connection
- A variable-frequency square-wave output
- A vacuum connection to the inlet manifold
This particular component can be either an integral part to the electronic control module or an individual component. The output from the external MAP sensor will show a square wave its frequency will be lower at idle than when the throttle is opened. The example waveform clearly demonstrates the output signal and when the frequency is also displayed can be compared against the model’s specification.
A higher frequency could result from any number of problems, but could be as simple as a split vacuum hose or incorrectly adjusted tappet clearances. Prolonged exposure to this higher frequency can result in damage to the catalytic converter.
Share
Help!