There are two methods to calibrate coolant/Inlet air temp. sensors (and any thermistors for that matter). The first is using factory supplied data for the sensors you're using, the second, although not as accurate, is by measuring the temperature of the sensor by heating it slowing and updating MEITE as it passes through different points. Both are described below.


For information on wiring of temperature sensors, please see here.

Method 1: Using Factory Data


Most new sensors have a data-sheet which describes their resistance for a given temperature.


MEITE has a range of pre-set calibrations for various sensors built in, and also, our Plug-In models has the OEM sensors already calibrated in the basemaps we offer.


The in-built pull-up resistors in all ME products are fixed at 2K7, which means you can work in OHMs when setting up thermistors in MEITE. This makes calibration quick and easy. Be sure to set your units appropriately in MEITE.


Simply enter your data from the supplied table into the correct HRT for the chosen sensor. Below, we can see the factory data for a Bosch coolant sensor, and the corresponding CLT HRT after entering the data.


Note you have 16 'rows' in the HRT system, so pick data points that cover the expected range you'll be working with. After entering the data (note the datasheet is in "Kohms" so 0.62=620Ohms) into the CLT HRT the below will be shown:


Image result for bosch coolant temperature sensor datasheet


Tip: If you see very high resistance (or voltage nearing 5V) on one of the IAT or CLT lines, then you likely have that circuit ‘open’ - ie.. the ground or signal line are not properly connected to that sensor. Try unplugging one of the sensors to see how the value reads in what would be a ‘fault’ condition.


Method 2: Calibrating by Testing


The other option to calibrate thermistors is to use a multimeter to measure the resistance of the sensor. Next, use a series of different temperatures such as a cup of cooling water and with a thermometer record the temperature of the water (as it cools from boiling) with the sensor immersed, record a table of temperatures vs resistances. This will give good ball park data for the table. Ice can be used for 0*C or less. A baked potato makes a great of getting over 100*C also!


Enter the data you discover into the HRT as per the above.