Function
It tells the control unit the intake air temperature in order to calculate oxygen presence so as to optimise the petrol quantity necessary for correct combustion.
Operating principle
NTC type sensor (resistance sensor, inversely variable with temperature).
Level in wiring diagram: Temperature sensors
Location:
- on the vehicle: on filter casing
- on connector sensor: near the probes
Electrical characteristics:
- Resistance at 0°: 32.5 kΩ +/- 5%
- Resistance at 25°: 10.0 kΩ +/- 5%
Pin-out:
- 1. 0-5 V signal: PIN 1
- 2. Ground connection: PIN 2
Caution! Before carrying out any troubleshooting, carefully read the general troubleshooting concepts for electrical devices at the beginning of the check and control section in the electrical system chapter.
Axone: parameters
Air temperature
- Example value: 26°C
In case of recovery, this value is set by the control unit.
Air Temp. before Recovery
- Example value: -40°C
Value drawn from the signal read without taking into account any recovery: the value in the example refers to an open circuit.
Axone: electrical errors
air temperature sensor P0110 - open circuit, shorted to positive / shorted to negative.
Error cause
If the circuit is open, shorted to positive: excessive voltage has been detected at PIN 63 of the ENGINE connector. If shorted to negative: voltage equal to zero has been detected at PIN 63 of the ENGINE connector.
Troubleshooting
If the circuit is open, shorted to positive: check the sensor connector and the Marelli control unit connector. If they are OK, check sensor continuity: replace the sensor if not OK; if it is OK, check continuity between the ENGINE connector PIN 63 and the sensor PIN 1: restore cable harness if there is not continuity; if it is OK, reconnect the control unit connector and, with key set to key ON, check the continuity between the sensor connector PIN 2 and the vehicle ground connection: if it is OK, it means that the error cause is that the cable is short circuit to positive and it is necessary to restore the cable harness between the ENGINE PIN 63 and the sensor PIN 1; check the sensor connector and the Marelli control unit connector. If not OK, restore the cable harness. If OK, check continuity between the ENGINE connector PIN 35 and the sensor connector PIN 2: restore the cable harness if there is not continuity. If there is, it means that the control unit does not supply the ground connection and therefore should be replaced.
If shorted to negative, check sensor correct resistance: if resistance = 0, replace the sensor; if resistance is correct, it means that the cable has ground connection: restore the cable harness.
Note. No error is detected if the sensor does not work correctly or the control unit connector or sensor terminals are rusty: then check through Axone if the temperature indicated is plausible in relation to the ambient temperature. Check also that the sensor electrical characteristics are observed: replace the sensor if not OK; if it is OK, check the sensor connector and the Marelli control unit connector.