How does the resistance of an IAT sensor change?
The IAT sensor is nothing more than a thermistor. That is; a resistance that changes its ohmic value as temperature changes. The thermistor used in the IAT has a negative coefficient, which means that the higher the temperature, the lower the resistance in ohms.
What happens when a Lexus trouble code is not cleared?
If the diagnostic trouble code is not cleared, it will be retained by the ECU and appear along with a new DTC in future trouble codes. If it is necessary to work on engine components requiring removal of the battery ground cable, confirm no DTC’s are stored.
Where to find OBD1 code on Lexus SC300?
Transmission must be in Neutral position. All accessories must be turned Off. On pre-OBD II models, turn ignition to On, then use a jumper wire to connect terminals TE1 and El of the data link connector, located under the left hand side of the instrument panel. Codes are indicated by the number of flashes of the check engine warning light.
What kind of resistor do I need for IAT?
Let’s say it measures 4600 ohms, then you may use a commonly available 4700 ohms (4.7k) resistor in series with the IAT. The above procedure is easy if the IAT is separate from the MAF. Otherwise, you will need to use a cooling spray as a source of low temperature for getting the needed equivalent to 50 degrees resistance value.
The IAT sensor is nothing more than a thermistor. That is; a resistance that changes its ohmic value as temperature changes. The thermistor used in the IAT has a negative coefficient, which means that the higher the temperature, the lower the resistance in ohms.
Let’s say it measures 4600 ohms, then you may use a commonly available 4700 ohms (4.7k) resistor in series with the IAT. The above procedure is easy if the IAT is separate from the MAF. Otherwise, you will need to use a cooling spray as a source of low temperature for getting the needed equivalent to 50 degrees resistance value.
What does the negative coefficient of the IAT mean?
The thermistor used in the IAT has a negative coefficient, which means that the higher the temperature, the lower the resistance in ohms. That being said, as you may deduct so far, if you want the computer to “think” that air is colder than it really is, then a reading of a higher resistance from the IAT is what we are looking for.
How many ohms does an IAT thermistor have?
Many IATs go as low as 200 Ohms when hot around 100 degrees Fahrenheit and go up to 5000 – 7000 ohms at low temperatures like 30-50 degrees Feranheith. This is only an approximation, as all IAT thermistors have s slight different response, but always with a negative coefficient.