Citroen C3 cooling fan issue

[olimkd]

Hello everyone .
Following the forum for long time and its been very useful so far.
Unfortunately have to write for the first time cos cant find the solution for my problem.
My Citroen C3 1.1 petrol 2006 120k km , first owner , don't start the cooling fan when it reach 106 C . the check engine light comes on the engine starts to misfire.
OBD says P0201, P0202, P1338, P0313.
After erasing the codes car runs great until i got stuck in traffic and the fan is not starting, then the check engine light blinking misfires again. erase the codes the C3 works fine again.
When i turn the A/C fan works .
when i unplug temperature sensor from thermostat the OBD reads -24 and the fun starts to work on high speed. (btw the sensor is new)
the resistor is also new .
All the fuses are OK , the main , inside , and on the BSI.
It happens every time i got in traffic, on highway never .
so after reading all the topics for this problem , i guess its the ECU. or maybe not.
Any suggestions are appreciated.

VIN VF7**************[VIN obfuscated, can be read by forum staff]

[olimkd]

what should i check before i go to ECU specialist ?

[ozvtr]

the check engine light comes on the engine starts to misfire.
OBD says P0201, P0202, P1338, P0313.

I would start replacing the fuel injectors.

After erasing the codes car runs great until i got stuck in traffic and the fan is not starting, then the check engine light blinking misfires again. erase the codes the C3 works fine again.

How do you know the fan is not running when you are stuck in traffic?

When i turn the A/C fan works .
when i unplug temperature sensor from thermostat the OBD reads -24 and the fun starts to work on high speed. (btw the sensor is new)
the resistor is also new .

The fan is fine. If the engine coolant temperature on the instrument cluster remains in the "normal" region, the the engine cooling system is fine.
If not, start looking at the thermostat or the radiator.

[olimkd]

Thx @ozvtr for reply.
Injectors are checked tested and in good condition. (also new fuel filter)
Unfortunately my C3 doesn't have instrument on the dash for temperature only warning light.
As the problem is annoying i drove several time to work and back with OBD reader plug in, monitoring LiveData reader.
Even on the parking standing still, the temperature goes up to 106C the fan doesn't start , only after this T is reached the check engine light start to blink car starts to misfire .
After it cool down a bit works normally again.

[olimkd]

update :
1. A/C not working any more, no cold air, when i turn the A/C the fan doesn't start.
2. when i plug out the temperature sensor the fan doesn't start.

the fan works with direct current .

[ozvtr]

You need to work one problem at a time.
I would concentrate on the P0201, P0202, P1338, P0313 error codes.
The engine ECU says there is a problem and the engine not running properly says there is a problem.
In the very least I would swap the injectors around and see if the fault moves. So far the engine ECU says there is a problem with injectors 1 and 2. If the fault moves, the problem is with the injectors. If the fault remains the same, it's the connectors, wring or the engine ECU.
You can also start with the basics and check the battery and connections. Look for corrosion, water ingress and damage to the wiring ad connectors.

[olimkd]

thx @ozvtr
already swap the injectors , the fault doesn't move, i swap 1st injector with 4th , same codes appear.
Cant notice any corrosion on ECU or elsewhere. No visual damage to the wiring also.
The summer is picking up extremely hot , we got over 40C here.
When i go to work in the morning C3 is just doing fine , but on the way back in the afternoon its same all over again, fan doesn't kick in and the engine starts to misfire. After it cools down a bit its great again.
Its holidays seasons so its kind of hard to find used ECU now.
Can i bypass cooling resistor somehow and turn fan manually ?

[ozvtr]

If the fault remains the same and there is no problems with the wiring or the connectors then the problem is going to be with the engine ECU...it's overheating.
You need to find some way to cool it down. Get more outside airflow across the ECU.
Do you still have the battery covers on the battery? You could try removing them.

The cooling fan circuit might be damaged, causing the engine ECU to stop the A/C from working. Unfortunately by-passing it will cause the fan to come on but it probably wont make the A/C work.
Unfortunately there are a lot of different radiator fan circuits and I don't know which one you have. You could tell us your VIN and ask Marc (givemeabreak) for a circuit diagram.

[olimkd]

i wrote the VIN in the first post .
do i need to write it again?
since i open the hood quite often these days the battery covers are out.
i traced the cooling fan circuit wires back to ECU and BSI all good for resistance.
@givemeabreak

[ozvtr]

i wrote the VIN in the first post .
do i need to write it again?

Now, be nice.
PM Marc. He may have missed this post.

[seanrx]

If you can't repair, you can diy install a switch in your cabin to operate the fan yourself. Wire runs from switch to fan relay.

I have in my own C5. Works great.
This was after much investigating of fan relays and wiring. And my garage couldn't fix it either.

[olimkd]

If you can't repair, you can diy install a switch in your cabin to operate the fan yourself. Wire runs from switch to fan relay.

I have in my own C5. Works great.
This was after much investigating of fan relays and wiring. And my garage couldn't fix it either.

does your C5 has regular relay? or its cooling fan relay resistor?
im not sure e.g dont know how to bypass my C3 resistor cos its 2 + 4 wires

[seanrx]

Two relay types? Not know this for my car.

It's been three years now but there is only 1 feed wire* to cabin switch and another from switch to earth. (Lower A pillar)
Wires between relay and ECU, none.

* Push power wire through the bonnet cable bulkhead rubber seal. You'll need a piece of thick stiff wire to help with this.

The switch system is always live, constant battery power to relay box by the fan. Cabin switch to earth and fan is on.
Also two fuses in the system wiring for safety. Between relay to cabin switch and relay to fan.

And the fan is one speed only! If your fan is multi speed it will spin at highest setting.

[olimkd]

Two relay types? Not know this for my car.

Radiator Fan Motor Relay Resistor for my C3… is far from regular relay

[seanrx]

Really?
So nothing in your fan wiring that's a sealed round/square plastic box with 4/5 flat pins sticking out downwards?