Analogue Temperature Inputs (T# in the Analog Settings and ANA Tx in Pinout/Wiring Diagrams) are direct 0-5V inputs to the ECU that feature a 2,700 Ohm pull-up to 5V internally.


They should be used with sensors that offer a varying resistance to ground, such as temperature thermistors.


Because the internal pull-up reference is known (2K7 to 5v), you can set MEITE to show the measured resistance (in ohms) of these sensors when working with them, making calibrating them easier.


They are protected, high impedance inputs.


Over-voltage should be avoided where possible as damage to the input can occur if excessive repeated over-voltage spikes occur.


A diagram of the Thermistor (for example a coolant or IAT 2 pin sensor) based circuit is shown below.


The resultant voltage at the ANA-T pin is then read by the ECUs ADC Systems block, which then reports this to the control algorithms.


A couple of a examples of how this works:

If the NTC Thermistors value matches the internal 2,700 ohms, then the ADC System will read ½ of the 5V internal reference, so 2.5 volts.

If the NTC Thermistor is disconnected (infinite resistance to ground) then the ADC System will simply read the 5V directly - (if you see 5V or very close to it on an ANA-T pin, then you may have either broken wiring or a faulty sensor.)


If the ANA-T pin is shorted to ground then the RAW/Sensor System will read ZERO volts - again a good diagnostic step if you think a sensor may be faulty is to bridge its wiring - if you see the RAW/Sensor System drop to approx. 0 volts, then you know the wiring is OK. 


If you see no change, then you have a wiring or assignment fault.


Enter your sensors calibration data directly into MEITE under the HRT tables, for the chosen sensor you have mapped the input to from the Inputs->ADC Settings.

Always sanity check the readings after doing so.