Checking the MAFS Waveform
The ECM constantly compares the signals from the air mass sensor and the throttle position sensor. When accelerating, the output voltage of the sensor increases, while decelerating, it decreases
MAFS characteristic
Air flow sensor
Air consumption, kg/h (at 20°C) | Voltage, V |
4,9 | 0,7 |
7,3 | 0,9 |
12,2 | 1,18 |
20,8 | 1,51 |
28,3 | 1,73 |
38,9 | 1,97 |
64,7 | 2,4 |
113,3 | 2,9 |
185,3 | 3,35 |
256,0 | 3,64 |
494,0 | 4,07 |
476,7 | 4,25 |
603,3 | 4,65 |
Note: If the output voltage is 0.0V or 5.0V, the sensor is damaged and needs to be replaced.
Checking the air temperature sensor
Measure the resistance of the sensor circuit between pins 1 and 5 and compare the result with the table below.
IATS characteristic
Temperatures | Resistance |
-40°С | 41.26-47.49 kOhm |
-20°С | 14.26-16.02 kOhm |
0°C | 5500-8050 Ohm |
20°C | 2350-2540 Ohm |
40°С | 1110-1190 ohm |
80°С | 310-320 ohm |
Wiring check
With the ignition on, measure the voltage between the specified contacts of the wired part of the connector.
Circuit under test | Rated voltage |
Contact 2 - «weight» | B+ |
Pin 5 - «weight» | 5 V |
Pin 2 - Pin 4 | Below B+ by about 200 mV |
Pin 1 - Pin 2 | |
Pin 1 - Pin 5 |
1. «Weight» sensor
2. Nutrition (B+)
3. Air flow signal
4. «Weight»
5. Air temperature alarm
Use an ohmmeter to measure the resistance between pins 3 and 4. Rated value: ∞ ohm.