c4_man Posted February 17, 2015 Posted February 17, 2015 Hi all, I recently purchased 2005 year C4. Quite nice car, but now I have few problems. One of them is quite serious for me. On 31th december I visited dealer for the software update. I had a problematic cruise control. Update fixed that and now it is OK. I noticed they have filled the fuel tank also. About month after that I went back, because cabin heater heated too much. When I selected 16 degrees C, it was too hot also. Well, they changed some parts and I got the car back. Again full tank. Anyway, this heater repair kit did not solve my problem. So maybe someone can suggest what to check? I do not know why it is overheating. But this full tank made me suspicious. But I continued my journey. Day after that, engine stopped and did not start again. I realized that tank was empty, even though indicator shows it's full. I added some fuel and it still shows full tank. After about 200 km, fuel amount decreases.. by the indicator... I was happy.. maybe it calibrates itself after some time.. today I started the car and again tank was full.. but it isn't.. There should be around 15 litres or so. Dealer do not know whats wrong.. maybe someone here can help me. Fuel indicator contacts in tank are nice. Quote
c4_man Posted February 17, 2015 Author Posted February 17, 2015 Forgot to mention, it is 1.6 litre 80kW petrol engine. Quote
paul.h Posted February 17, 2015 Posted February 17, 2015 Welcome to the forum. If you disconnect the fuel tank level electrical connector does the indicated level then show no level - if not then it is most likely a problem with the software update since it started then (or if they disturbed the wiring behind the dash then maybe they caused a wiring fault). In this case I would ask the dealer to redo the software update or even put the old one back to prove the fault. If the indicated level does fall, then it could just be a coincidence the problem started when the software was updated and it could be the fuel level sensor (or its wiring) has developed a fault. You could measure the resistance across the sensor electrical pins and then put more fuel in and see if it changes. You could even remove the sensor (has a fuel pump as part of it), seal the tank opening to stop any petrol fumes and risk of igniting them, connect the sensor again and then watch the indicated level as you move the sensor float. Did the heating work correctly before the software update but then developed the fault straight away - if so then again the software may be the problem. If the problem happened sometime after the update then for some reason the warm air flap in the heating can not be moving. This could be a controller problem, a temperature sensor problem, a flap control motor problem or its connection to the flap. Sometimes electrical problems can be fixed by doing a battery disconnection/reconnection and in the Technical section Common Problems pinned topic there is a procedure I have used that has not resulted in odd electrical problems. Quote
c4_man Posted February 17, 2015 Author Posted February 17, 2015 Thank you Paul! This information is very helpful. I will try to measure resistance and so. Yes, the overheating problem started after update. I will contact with dealer and try to sort it out. Quote
c4_man Posted February 19, 2015 Author Posted February 19, 2015 It seems some kind of software issue. I took fuel level sensor with fuel pump out of the tank and measured resistance. "Full tank" resistance was about 79 ohms and "empty tank" resistance about 400 Ohms. Currently I have about half full and resistance is 250 ohms. I assume level sensor is working properly. When I removed fuel pump and level sensor connector and turned ignition on, then indicator still showed full tank. Hopefully next week dealer will take the car in and try to sort it out. Quote
paul.h Posted February 19, 2015 Posted February 19, 2015 Good luck with the dealer, definately sounds as if the level sensor is ok from your tests. Quote
druid Posted February 26, 2015 Posted February 26, 2015 I have a similar problem if someone could help please.Car went in for full service 2 days ago, oil,filter,diesel filter, air filter etc just filled up with fuel right to very top and the gauge is still reading a bar from the top empty and the trip display is still reading what it was before the service.Any ideas on what could be wrong? Could changing any of the filters etc have caused this fault?Many Thanks Quote
paul.h Posted February 26, 2015 Posted February 26, 2015 If the service on your C4 2006 1.6HDI was done by a Citroen dealer they may have done a software update which caused the problem. I would contact them to see what they did. I have deleted your similar post so all replies are kept in one place. Quote
druid Posted February 26, 2015 Posted February 26, 2015 Hi PaulThanks for your reply.No software update was done only the jobs that are stated above were done.Any ideas? Quote
paul.h Posted February 26, 2015 Posted February 26, 2015 On the trip display, if this is the mpg/miles covered/miles left to empty one, have you tried to reset it by holding in the button on the end of the wiper stalk ? These only go up to the equivalent of 9999 km and then stop (about 6300 miles), otherwise an extra digit would be needed. If it is the miles covered on the speedo then these go up to 1500 miles (I think) and then start again at 0 miles. If it is the miles to next service display, then on Citroens it can usually be reset by holding in the speedo trip button, turning the ignition key so the dash lights up and then waiting for it to count down to =0, then release the button - but check this in your handbook. For the fuel tank level, try the electrical connection resistance checks in the previous posts, just in case it is a coincidence the level sensor is not working after the service. How much fuel did you put in the tank to fill it up ? Quote
druid Posted February 27, 2015 Posted February 27, 2015 HiI filled it over flowing as the fuel came out from the over flow pipe so I know its full. Quote
c4_man Posted February 28, 2015 Author Posted February 28, 2015 I haven't got any feedback from dealer. They're not sure whether they have previous software version or not. Still waiting... Quote
c4_man Posted March 2, 2015 Author Posted March 2, 2015 Can someone send or post here fuel level sensor wiring diagram? Where are these fuel level sensor wires connected? I would like to test them. Hope someone can help. Quote
paul.h Posted March 2, 2015 Posted March 2, 2015 The only Haynes manual I have that shows the level sensor is for a C3. It shows the wires from the level sensor/fuel pump go to the bsi which will then generate the signal for the level gauge. Usually the wiring goes from the back along the left hand sill to the bsi/dash fuse box - so you could try and follow the wiring by its colour or number code (magnifying glass will help to see this). If looking for a short to earth you could disconnect the plug at the fuel tank end, put a meter lead to an earth point and the other to the different pins in the connector - if there is a short to earth then you should get a very low resistance. Quote
c4_man Posted March 3, 2015 Author Posted March 3, 2015 Thanks. I will try to sort it out. There are two ECUs under the bonnet with many wires. I will try to trace colors and numbers. I suspect that maybe these level sensor wires are damaged and this could cause problems. Quote
paul.h Posted March 3, 2015 Posted March 3, 2015 I have found a wiring diagram in the French RTA manual for the C4 1.6 petrol and this shows the fuel pump/gauge having 2 wires. One comes from the engine fusebox fuse 5 and is numbered 1201L and the other numbered MC123 goes to a wire MCBSI from the BSI which becomes MC46P and goes to an earth point MC46 (E4 in the Haynes manual)- this may be near the BSI so possibly at the door side of the passenger footwell or a bit higher. So if the diagram is correct and you only have 2 wires, 1 will supply 12 volts and the other will be an earth. How this lets the level gauge work I do not know since I would expect the gauge to have its own wire back to the BSI so it can calculate the level from it. Wiring numbers often change so may not be correct. Quote
c4_man Posted March 3, 2015 Author Posted March 3, 2015 Yes, fuel level sensor has two wires and fuel pump also two wires. So,totally four wires in connector. I measured them (fuel level sensor ones) and one is connected to ground. The other one isn't.Maybe it is stupid question, but is this ECU or ECM same as BSI? Or where shoud I look for this BSI? Quote
paul.h Posted March 3, 2015 Posted March 3, 2015 The BSI (built-in systems interface) is the glove box dash fuse box and controls lots of things which normally use relays and separate controllers. There is also an engine ecu and other ecus for other things. Quote
c4_man Posted March 12, 2015 Author Posted March 12, 2015 Now it is sure that they cannot put the old software version back. Seems that I have to live with the wrong fuel level. If the dealer does not know what to do, then who else knows... Quote
paul.h Posted March 13, 2015 Posted March 13, 2015 Maybe they should reload the new software in case it was not done properly. Quote
c4_man Posted March 17, 2015 Author Posted March 17, 2015 Paul, thank you for the help. My problem is solved. Today dealer deleted software and reinstalled it. Now fuel level indicator works as it should be. Quote
paul.h Posted March 17, 2015 Posted March 17, 2015 I am pleased it is sorted, there must have been a problem when the software was first installed and for the problem to have started just after it would have meant an unlikely coincidence for it to have been caused by anything else. Quote
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