Peugeot 3008 1.6 THP 156hp - Radiator fan constantly running at high speed | PEUGEOT

What exactly is the error code that is stored? Has the wiring already been checked under load?

P2279 Error Code Intake Air Flow Coherence Permanent

The P2279 indicates a leak in your intake manifold. This will not cause the fan to run constantly. However, you should have the intake system checked for leaks.

Regarding your fan, I would have the cooling system vacuum-bled. Has the wiring from the temperature sensor been tested under load to the engine control unit?

The cooling system has already been vacuum bled and filled. The wiring from the temperature sensor as well as the complete thermostat housing has already been replaced. Also the radiator fan control unit. Of course, original Peugeot or PSA. My suspicion is more the engine control unit itself. Could this be it? Or rather the air conditioning? Maybe the attached picture is helpful.

Peugeot once had a problem where the fan would run constantly due to false air intake. So, have the system checked for air leaks. Check the oil filler cap, oil dipstick, damaged hoses, engine ventilation, etc. That should also solve the fan issue.

Is the OE temperature sensor installed?

Measure the sensor connector with a multimeter.

Everything has already been done. Valve cover, oil cap, hoses all new.

All original parts were used

What strongly bothers me in the picture is that you are getting sub-zero temperatures displayed. This is usually the case when a sensor is not recognized and the ECU then takes a substitute value and goes into emergency mode. Did I understand correctly that you have already redone the wiring to the temp sensor?

Yes, the thermostat housing and wiring are all new original Peugeot PSA parts. There was a technical modification because there were problems. I got everything from the dealer. A proud 200€ for the thermostat housing and wiring. All in all, almost 2000€ have already been sunk into the engine. And the fan error is still there. I'm slowly getting clueless. Especially since I had used an accessory thermostat housing the first time and now expected a better result with the original part.

For this error code, check the mass airflow sensor; this is almost certainly your problem. The last ones with this error were always defective mass airflow sensors. The error code indicates charge air above the setpoint.

So your car isn't really warming up at all?

So the temperature gauge goes up to 90 normally.

Do you have target values for this?

Checking the mass airflow sensor with a multimeter

It is even more reliable to check the function of the MAF sensor using a multimeter. The mass airflow sensor communicates with the control unit via a DC voltage signal that changes proportionally to the amount of air used (at idle). When the accelerator pedal is pressed, the measured value on the multimeter display should increase if the mass airflow sensor is working properly. If, on the other hand, the DC voltage remains unchanged when the engine speed is increased, there is a defect in the MAF sensor. The advantage of these two methods is that they are easy to implement and relatively reliable. In addition, these tests can even be carried out by technically experienced laypersons in their home garage.

Do you happen to know the location of the MAF sensor on the 1.6 THP? It doesn't have a classic MAF sensor like the ones used by the VAG Group.

Do you have the key numbers or the vehicle identification number (VIN)?

It will not have a mass air flow sensor. If the selection is correct, the EP6C has an intake manifold pressure sensor, which measures the intake manifold pressure and air temperature. It is located on the intake manifold opposite the throttle valve.

I thought so, that it doesn't have one. But all the sensors around the engine have already been renewed.

Do you have the registration certificate numbers and the VIN? What fault codes are stored?