Technical Temperature Gauge Problem

[puntogiz]

HI

My 1.2 MK2b 2004 Punto temperature gauge has been playing up for a while now on long drive it will drop to zero for 30 seconds then goes back to normal , then goes again to zero again and the EML comes on with the fan, the next day it always goes to normal temp with the EMLgoing off.

Also have the temp gauge to over heating for say 30 seconds then go back to normal.

I have replaced the coolant sensor but it's still the same problem.

 

[judderbar]

HI

My 1.2 MK2b 2004 Punto temperature gauge has been playing up for a while now on long drive it will drop to zero for 30 seconds then goes back to normal , then goes again to zero again and the EML comes on with the fan, the next day it always goes to normal temp with the EMLgoing off.

Also have the temp gauge to over heating for say 30 seconds then go back to normal.

I have replaced the coolant sensor but it's still the same problem.

Could be a connector problem. The temperature sensor is a resistor. If the connector is not working at all, the measured resistance is high, the gauge will be zero and the fan will run. If the wires are touching the measured resistance is low and the gauge goes high.

 

[judderbar]

I was thinking later that I got that reversed with the resistances but Haynes manual has some resistance measurements for the sensor.

0C 5.97 k Ohms,
50C 0.8 k Ohms
100C 0.17 k Ohms

On my car the gauge begins moving 50C

 

[majobusa]

Same issue here, although with Grande Punto and 1.3 mjet engine. I've exchanged the temperature sensor, cleaned the connector and deleted the error with Multiecuscan but still not solved. I noticed yesterday that it drops to zero when fan starts, I 'll check the fan connector, just in case...

 

[puntogiz]

Only happens when the car has been on long journey.

 

[majobusa]

Yes, after one hour or so.

 

[Mike1alike]

How is the antifreeze level?
Air pockets in the cooling system can cause this.
That sounds like real problem on the cooling system, not just bad reading of temperature.
I think thermostat needs to be replaced maybe.

 

[danielP]

I have the excact same problem. changed the sensor and cleaned all the connectors but nothing changed. tomorrow i'm going to change the thermostat and see if it makes any difference.

 

[dakatana]

Check dash connector for some oxidation...with odb check the temperature are ok..the sensor has 2 ntc inside...1 for ecu and 1 for the dash

 

[woolfie]

Troops did you solve the problem on this one . My doblo cargo is now experiencing the same problems . Looking for help to where to start first