The EMS light stays on my fiat punto grande 07 and the engine is difficult to start when cold and the fan motor starts when the engine is switched on and the temp gague doesn't work at first. Eventually coming on but only when the engine has warmed up and the engine is switched off and then on a few times. Any idea what is wrong with my car?

All sounds like its linked to a failed temp sender unit, or the wiring too it. When gauge works the fan turns off I take it?

So you don't think it could be the thermostat problem? When I turn my engine off and on a few times and its warmed up the radiator fan then stops and the temp gague starts working. Was thinking of replacing the thermostat. Any other ideas?

SteveGriff10 said:

So you don't think it could be the thermostat problem? When I turn my engine off and on a few times and its warmed up the radiator fan then stops and the temp gague starts working. Was thinking of replacing the thermostat. Any other ideas?

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Fan running when cold is a sign the temp sensor isn't connect or has failed as its a fail safe, the fact temp display doesn't work when it does this confirmed this also.

Correct, the temp display gague doesn't work when the fan is running but after ive left the engine running for a couple of minutes and then turn the engine off and then on again a few times the temp gague comes back on and the fan stops. But the engine management light is constantly on. Help??

SteveGriff10 said:

Help??

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What more do you want me to say?

Only way to get a definite answer would be to get the fault codes read

Any other advice?

SteveGriff10 said:

Any other advice?

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Not without fault codes. It'd be stabbing in the dark which isn't the best of moves.

Changed the MAP sensor and the coolant temperature sensor but the check engine light is still on? What else could it be? Or how do I reset the engine error light?

SteveGriff10 said:

Changed the MAP sensor and the coolant temperature sensor but the check engine light is still on? What else could it be? Or how do I reset the engine error light?

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So what was the fault code in the end? Or did you not bother getting it read

P0115 - the coolant temperature sensor. Which I have changed.

SteveGriff10 said:

P0115 - the coolant temperature sensor. Which I have changed.

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Did you check the sensor had the correct voltage supply/earth, or just replace it because the computer said so? Very often it's actually a wiring/connector issue that causes an error code- all the ECU can see is that it's not receiving the signals it expects, so flags up a fault- it doesn't know why.

Years ago I had a Panda with a similar issue- fan running constantly and a coolant temp sensor error logged. I could have assumed it was the sensor, but I checked the voltage at the connector- no supply. Traced the wire back to the ECU- still no supply. In a total random occurance, the output supply from the ECU had died.

From plugging in the diagnostic computer, to getting the wiring diagram and tracing the fault to the ECU- all in the 1 hour diagnostic we charged the customer. Granted , I know a lot of Techs who would've taken the easier option of just reading the code and condemning the sensor, but it always comes back and bites them eventually.


Now, you say you're getting the "Excess radiator temp" message- is this only on first start-up? If so, have a read of the common faults thread at the top (ECU update required, or at least, a decent battery). If it's coming up later on, then I'd be checking that your car isn't actually overheating/ has an airlock around the sensor/ has a failing headgasket.

You also say the gauge eventually starts working after a while/repeated start-ups- does it rise to the normal level? Is the cooling fan still running constantly? etc.

And finally,

https://www.fiatforum.com/grande-punto/339270-coolant-temperature-sensor.html

https://www.fiatforum.com/grande-punto/339215-replaced-map-sensor-coolant-temperature-sensor.html

You'll find an answer much quicker (and upset the mods less) if you keep it all in one thread.

I have changed the map and coolant temperature sensors and the faults seem to have gone but the engine management light is still on and i had the excess radiant temperature ertor again. If its the connector or wiring where can i get new wiring from? Also how would i go about testing and changing the output supply from the ecu thanks?