DMRV signal (mass air flow sensor) is a DC voltage whose value depends on the amount and direction of air flow through the sensor.
An air temperature sensor is built into the mass air flow sensor, the sensing element of which is a thermistor installed in the air stream. At low temperature, the resistance of the mass air flow sensor is high, and at high temperature, it is low (tab. 9.6).
If the air temperature sensor is faulty, the controller memorizes the error code and turns on the signaling device, while the readings of the faulty sensor are replaced by the controller with a fixed air temperature value of 33°C.
To replace the DMRV (mass air flow sensor) by car you will need: a key «on 10», Phillips screwdriver.
1. Disconnect the wire from the terminal «minus» battery.
2. Having pressed the plastic latch from the bottom with a screwdriver or finger, disconnect the wiring harness connector from the mass air flow sensor. Loosen the fastening clamp and disconnect the air supply hose from the DMRV (mass air flow sensor). Loosen the two fixing screws and remove the MAF (mass air flow sensor) from the air filter.
3. Install the DMRV on the car (mass air flow sensor) in reverse order. Pay attention to the condition of the rubber gasket, as damage to it can lead to interruptions in the engine.
Table 9.6. The dependence of the resistance of the air temperature sensor on the temperature of the intake air (allowable error 10%)
Intake air temperature,°C | Resistance, Ohm |
-40 -30 -20 -10 0 +10 +20 +30 +40 +50 +60 +70 +80 +90 +100 +110 +120 | 39,2 23 13,9 8,6 5,5 3,6 2,4 1,7 1,2 0,84 0,6 0,45 0,34 0,26 0,2 0,16 0,13 |