Renault Twingo 1 / 98r: Dealing with P0115 - Engine Coolant Temperature Sensor Fault

Hello
I recently bought Twingo from 98 and how is it reno; P

Well, the problem is that the fan does not work in 1st gear and the controller displays error P0115 - Engine coolant temperature sensor - permanent fault.

I was at the mechanic's with it, but he spread his hands, claims that he lacks the sensor on the radiator and his computer shows an overall ECU error. The car has air conditioning and when I drive with the air conditioning on, everything is great. After switching on, the fan turns slowly and maintains the engine temperature at 98-92 degrees. However, when I turn off the air conditioning, the temperature jumps to 102 degrees and only the fan starts up at full power so that it cools down to 80 in a few seconds.

Ok, I can understand that the designers did not give the sensor but then the computer should not cause an error. There is one sensor in the engine block, it works fine. After unfastening it shows -40 degrees.

The photo shows the engine temperature sensor - I will add that after unplugging it, there is no additional error, in total temperatures -40 can happen.


And here is a cooler, a fan at the top and a blower resistor on the left - it works when I disconnect it, there is no fan after starting the air conditioning. I wonder if the version with air conditioning may have sensors or something else, the mechanic told me that every car should have a sensor, but an ordinary bimetal on the radiator to turn on the fan.



D7F engine The same engine is found in the 99 Clio

Do you have any ideas?

There are two possible solutions: two sensors, one for the motor controller and the other for turning on the fan (bimetal) or one sensor only for the motor controller and this turns on the fan, but after disconnecting it, the fan should start working.
You say that after unfastening it shows -40. It shows on the meter if the computer says that the engine controller sees the temperature?
Sometimes there are two separate sensors - one for the meter so that the driver can see the temperature and the other for the engine controller to select the right dose of fuel.

Twingo does not have an indicator in the cabin.
-40 is the reading from OBD2, the Piston program describes it as the engine temperature and the Torque program as the fluid temperature (Connecting via a cheap bluetooth interface). However, I found no temperature reading other than the intake air temperature. As I mentioned, the mechanic's computer showed a general ECU error, but it was connected with it not as Twing but Clio because his program for Twing only provided for checking the ABS. However, after choosing the Clio it connected nicely (the same engine) and showed an ECU error and no fan speed 1. Interestingly, my friend has a Clio with the same engine and my interface could not connect to his car.
After unplugging the sensor, the fan does not start, the sensor has 3 pins, while the plug uses 2

The engine control unit controls the radiator fan via relays. Perhaps the engine control unit does not see one of the relays and hence the error.
I do not know if you are able to check with your equipment, but you should see something like the first gear has been controlled, so that you can see that when the engine is warmed up, the ECU reacts correctly and changes the state at the output, but the relay does not switch because it is damaged or is broken wire from the relay coil control between the relay and the ECU.
What is the year, engine and is it the PH1 or PH2 version?
There should be two relays - one from first gear and the other from second. The first gear is released by the resistors and the second runs the fan directly.
You need to locate the relay, check them and the continuity of the wire between their coils and the ECU.
They are ground controlled from the ECU.

Maybe I'll start from the inside
Renaul Twingo 1 98r D7F 60koni engine



This is my relay box. The two black small relays on the left side are fuel pump feed and coil feed, respectively. This gray one is an air conditioning relay, it simultaneously turns on two separate circuits, a fan and a generator (or what is it called, you know what it is about) ). And this circuit goes through the resistors, after removing the plug from the resistor, the fan stops, so it's good. The second relay, on the other hand, controls the fan. The relay contact is connected directly to the fan, there is nothing else, so it's the 2nd gear. He's working fine too. However, I do not have a fan fuse in the car. In the box in the car, the place for the radiator fan fuse is empty. Originally it is empty, there are no metal pins inside.
Today I'm going to a friend who has a Clio with the same engine and I will see how it works for him. I'll check the continuity tomorrow and maybe I'll check the computer again. If he originally does not have 1 gear, at most I will make a relay + bimetal + plug into the air conditioning system to go through the resistor. I just do not want to combine if there is no need and maybe some stupidity is damaged. And this mistake.

Since it has the first gear when the air conditioning is working, it should have it for normal cooling.
These relays are controlled by the ECU and it does not matter whether the air conditioning is or not, these relays should be.
When you close the relay contact with your finger, does the fan start, i.e. do both gears work as you close the relay contacts?
When you turn on the climate, does the first fan speed work, the one through the resistor?

The first gear uses only the air conditioning, the engine cooling immediately locks the second gear, after the temperature drops, the fan stops or works at 1 as the air conditioning is on - this is the original. Probably your thermostat is limping. Second thing, the computer displays stupid things, Twingo does not have an EOBD system and does not apply to PXXXX codes.

grala1 wrote:

When you close the relay contact with your finger, does the fan start, i.e. do both gears work as you close the relay contacts?
When you turn on the climate, does the first fan speed work, the one through the resistor?

Climate goes through the riser and cooling normally without

milejow wrote:

The first gear uses only the air conditioning, the engine cooling immediately locks the second gear, after the temperature drops, the fan stops or works at 1 as the air conditioning is on - this is the original.

I have just come to the same thing, I was at a friend who has Clio and he says that his windmill starts aggressively and only for a moment. My thermostat is functional, I can see exactly how the temperature drops at 92 degrees after opening the large circuit. In general, I was concerned that the fan turns on at 100 degrees, but on the other hand, if it does not have 1st gear at the factory, then if it had 94 degrees, the fan would keep turning on and off.

milejow wrote:

Second case, the computer displays stupid things, Twingo has no EOBD system and PXXXX codes do not apply to it.

The fact that it can display stupid things is right, I was watching Clio and it also has one temperature sensor. The description of the defect shows that my error will appear when the values go beyond some set limits, but everything is ok.
But please explain something to me. EOBD is simply European OBD. If I have an OBD2 connector and the data I transmit is more or less correct (I don't know why it shows 250 rpm when the engine is off), why can't I use the codes?
But overall thanks a lot for your help, since it's normal I can drive more calmly without fear that it will boil.

fidzos wrote:

(I don't know why it shows 250 rpm when the engine is off), why can't it use the codes?

The right interface / computer for the right car brand.
In "my" brand, from time to time, there are engine error readings with an inappropriate tool, and wrong translations, descriptions of these errors, in a word.
Unfortunately, they made protocols, diagnoscopes, and such general ones for all brands, are often too weak to properly communicate with the drivers in the car.
You can do something like that, but not that one, you have to connect another one - to that ...
Only the right one can be sure that he will communicate correctly and will give a helpful hint.

fidzos wrote:

the controller displays error P0115 - Engine coolant temperature sensor - permanent fault.

fidzos wrote:

There is one sensor in the engine block, it works fine. After unfastening it shows -40 degrees.

Besides stupid things, I would have a bad sensor, or a break in the wires. You don't have 5V on this plug? A colleague has an identical sensor? Will he turn?

fidzos wrote:

The description of the defect shows that my error will appear when the values go beyond some set limits, but everything is ok.

Yes, the sensor will show resistance indicating a temperature below -40C. See on my example a sensor with a thermistor
https://obrazki.elektroda.pl/1953657000_1502372910_thumb.jpg
The table ends with -20, although MY error as such description is below -35C, a mistake of a dozen K?> minor non-contact on the connections makes me a small sensor fault with these -35, then the minimum short-circuit current flows through such a sensor, and whatever which can reduce it even more, showing the lack of a sensor or a break in its connection.

Managed to
I borrowed an old temperature sensor from a friend and connected it through the cables. Probably from Fiat, it showed 26 degrees, but the error was; (So I decided to call the fault to check if my interface correctly interprets the errors. To create a fault, I fixed the old one, error P0115, contrary to the description in Reno, means a temperature sensor error, but not the fluid, but the intake. I even know what and how. Recently, we have very high heat, not only that the air filter is behind the engine, I also had a leaky housing and sucked hot air. The temperature had to exceed the scale and the fault was recorded and as you can see the ECU had to register "sensor replacement" to delete the error because I recently replaced the injectors and removed the entire throttle, so I unplugged the cable harness and the error remained.

So for posterity
Clio and Twingo from 98 have only one fan speed and only air conditioning goes through the resistor.
Error P0115 - intake temperature sensor error, from the bottom in the throttle

Thanks a lot for your help