Technical Radiator Fan Causes 'Check Engine' Light to Illuminate

[jamesrocklea]

Hi,

New to the forum so apologies for anything I shouldn't be doing.

I have a 2001 (Y Reg) Punto, 1.2L without air con.

Recently the check engine light has started to illuminate whenever the radiator fan turns on. The engine seems to behave itself if I keep it running. But the check engine light doesn't disappear until I erase it with the OBD reader. The OBD code indicates 'a coolant system malfunction'.


In addition if the car is turned off and back on again in a short amount of time (e.g. if the car stalls or if I get out to drop a letter off) before the engine has had a chance to cool, then the coolant temperature light illuminates immediately. The radiator fan doesn't operate whilst the engine coolant light is on, so the only way to get rid of this is to let the car cool completely so that only the check engine light shows.

I've drained the coolant system and replaced the thermostat thicking it could be an airlock, but still no change in the lights.

Thanks in advance for any help.

Kind Regards,

James

 

[Ziggy122]

a decent code reader will show up what i think will be Coolant temperature sensor failure

When the car cant Detect the cars coolant temperature, it goes into limp home mode

Some people lack power
Some dont

But they all do 3 things in common
- Put the engine fan on, to prevent overheating
- Over fuels, as overfueling makes the engine run cooler
- The EML will come on indicating a fault

Ziggy

 

[fingers99]

Could well be the coolant temp sensor is fubar.

 

[Brendan W]

Yeah sounds like the sensor or the wiring/plug. I test the fan by disconnecting the sensor and the red overtemp lamp comes on with the yellow eml lamp with the fan. I don't need to erase the eml lamp though it goes away by itself after two or three cycles of the motor.

 

[crazyfrenchbird]

I had similar problem on my 1.2 16v when I bought it 7 months ago. I had to change the temp sensor and the thermostat and clear the air locks in the radiator pipes and thru heater matrix and it sorted the problem

 

[stealthtuning]

Mine did the same. Mine was caused because the previous owner had taken out the stat. I think puntos have two coolant temp sensors, one says hot and one says cold, the fan cuts in and throws up the light.

Stealth

 

[s and b]

im with Brendan W and wiring/plug issue
i would get another one from scrappies and cut the old one off see if this solves it solder the new one in mind,no twisted cables in bog roll