How to measure the goodness of car sensors with a multimeter
1. crankshaft position sensor measurement method, to see the circuit diagram, see the circuit diagram to determine the use of active or passive, in the in the country there are two types of sensors, a Hall sensor, an electromagnetic sensor. Hall sensor has 3 wires, respectively, 5-volt power supply, signal, iron. Measurement method is to use the multimeter DC voltage level red pen to measure the signal, black pen directly on the negative pole! Here to tell you how to measure the signal, the sensor in the car, do not disassemble, plug and do not pull, with a thin wire in the back of the plug back plug measurement!
After linking a good line, use a wrench to turn the crankshaft pulley, slowly turn, if the crankshaft position sensor is good, you will find that the multimeter voltage a moment to show 0 degrees a moment to show 5 volts, do not turn too fast yourself. If not then the fault. The second is the magneto-electric crankshaft position sensor, it is relatively simple to measure, directly unplugged, there are 2 pins, with a multimeter AC voltage gear, red and black pens are connected to the two pins, and then linked to the line, start the engine, the engine crankshaft does not rotate no voltage, start the engine, you can see more than a dozen volts, may be higher indicating a good.
2 camshaft position sensor is Hall with the above Hall crankshaft sensor measurement method, he is also linked to a good line, I wrench slowly turn the crankshaft to see if there is a change in voltage, the need to open the ignition switch.
3 Intake air temperature sensor, intake air temperature sensor now models are integrated in the air flow meter, or manifold pressure sensor.
Air flow meter
Its measurement method is relatively simple, first of all, find the circuit diagram, find out the intake air temperature sensor pins are the two, intake air temperature sensor is generally a resistor, with the temperature changes, with a multimeter resistance file, black and red pens linked to find out the two pins, this sensor needs to be heated with a hair dryer. See if the resistance size changes, does not change the fault.
Manifold pressure sensor measurement method to find the same circuit diagram to see that is 5-volt power supply, that is the signal, that is the iron, the side of the amount of methods in the intake manifold to remove the intake pressure sensor, do not unplug, with a thin steel wire back insertion, the signal to lead out, with a multimeter DC voltage file, the red pen connected to the signal, the black pen iron, preferably the negative terminal of the battery! Use a vacuum to link to the intake pressure sensor interface, vacuum. You can see the voltage is changing, unchanged for the fault
