Function
It tells the engine temperature to the control unit so as to optimise its operation.
Operating principle
NTC type sensor (resistance sensor, inversely variable with temperature).
Level in wiring diagram: Temperature sensors
Location:
- on the vehicle: on the front cylinder on the internal side facing the rear cylinder
- connector: on the sensor
Electrical characteristics:
- Resistance at 25°: 2.05 kOhm +/- 100 Ohm
- Resistance at 60°: 575 Ohm +/- 15 Ohm
- Resistance at 90°: 230 Ohm +/- 5 Ohm
Pin-out:
- 1. Yellow brown: 0-5 V signal: PIN B1
- 2. Brown: PIN B2 ground connection
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
Engine temperature
- Example value: 75°C
In case of recovery, this value is set by the control unit.
Engine 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
engine temperature sensor P0115 - 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 45 of the ENGINE connector. If shorted to negative: voltage equal to zero has been detected at PIN 45 of the ENGINE connector.
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 the continuity between the ENGINE connector PIN 45 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 correct, 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 45 and the sensor PIN 1; if there is no continuity with the ground connection, 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 no continuity. If there is, it means that the control unit does not supply the ground connection and therefore should be replaced.
Troubleshooting
If shorted to negative, check sensor correct resistance: if resistance is null, replace the sensor; if resistance is correct, it means that the cable has ground connection: restore the cable harness.
Axone: logic errors
engine temperature sensor P0116 - signal not valid.
Error cause
An excessive temperature variation has been detected: for example, the cause may be a contact resistance between the terminals.
Troubleshooting
Check the sensor connector and the ENGINE connector of the Marelli control unit.
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 engine 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.