Guest HumanTank Posted September 22, 2008 Posted September 22, 2008 [Moderator edit 13/6/2013 - if you follow this posting to the end you will see this quick fix did not work and possibly ended up costing more to fix than the initial problem. Therefore it can not be recommended.] Under the ECU unit under the bonnet on the passenger side is a cable with a plug which is secured to the bottom of the ECU unit. ALL I DID WAS CUT THE YELLOW WIRE IN HALF and now i have the car back to A1 running you still get the errors on the dash but at least the car runs great now. Quote
kfk Posted September 22, 2008 Posted September 22, 2008 Under the ECU unit under the bonnet on the passenger side is a cable with a plug which is secured to the bottom of the ECU unit. ALL I DID WAS CUT THE YELLOW WIRE IN HALF and now i have the car back to A1 running you still get the errors on the dash but at least the car runs great now. what does the yellow wire do? Quote
Guest HumanTank Posted September 22, 2008 Posted September 22, 2008 what does the yellow wire do?IT STOPS THE 3000 REVS LIMP MODE KICKING IN AND MAKES THE CAR RUN FINE AGAIN Quote
smokescreen Posted September 23, 2008 Posted September 23, 2008 You ask a simple question you get a simple answer! Quote
kfk Posted September 23, 2008 Posted September 23, 2008 Maybe i should have asked how long the wire is so i know where half is.......i wouldnt want to cut it in the wrong place! Seriously though.......it would be interesting to have a bit more information about this work around to a problem........like what vehicle it relates too Quote
Guest HumanTank Posted September 23, 2008 Posted September 23, 2008 Maybe i should have asked how long the wire is so i know where half is.......i wouldnt want to cut it in the wrong place! Seriously though.......it would be interesting to have a bit more information about this work around to a problem........like what vehicle it relates too The car is a C8 2.0 HDI SX 2004 (diesel additive min level, antipolution message, and disel filter blocked all come on) symtons (lack of power, limit revs to 3000 bungy hopping) When i investigated what was causing this and to find the cost of the fix was about £700 i decided to try and do something myself to get round the problem. First what i noticed is when you undid your petrol cap for more than 10 secs power was restored for a minute or so (so it had to be the ECU telling the car what to do) So when you open your bonnet and see the ECU to the right as you are looking at it (passenger side) you will notice cabels going into the top (DO NOT TOUCH THEM) i noticed a cable coming round the left side of the ECU then a clip at the bottom of the ECU holding the joint connector then it goes round to the right of it. At first i just unplugged that connector and the car then came out of limp mode so you code still go over 3000 revs but the car still lacked power especially when going up hills but it worked so i ran it like that for awhile. Untill i thought to myself what if i plugged it back in but just diconnet 1 wire at a time by cutting through the wire (and the buy some wire connectors to connect them back if the wire that was cut did not do anything) and see if i can keep the power without the limp mode kicking in (which to be honest does not harm the car its just for CITROENS EMMISIONS comming out of the car) so lucky for me the cable that comes round the bottom left of the ECU i just pulled the black sleeve back leaving about 7 wires showing all different colours (it was like in the movies deciding which one to cut first like a bomb lol) So i just cut the YELLOW one started the engine and to my suprise i picked the right one (all the codes still comes on the dash as faults and the engine light is still on but the car feels like brand new to drive all power back with no jerking) The car was due for its M.O.T today so i have just picked it up with a PASS emissions past the test aswell. I hope this helps all the frustrated people out there. Quote
kfk Posted September 23, 2008 Posted September 23, 2008 The thing that concerns me here is that disconnecting the wire hasnt resolved the problem to a state that you can say you have 'repaired the vehicle'.Having checked out a wiring diagram i'm guessing you have disconnected the downstream exhaust gas high temperature sensor (black 10 way connector pin no 6) .....why this is causing the vehicle to come out of limp home mode i couldnt say. With regard to the blocked particle filter and additive require replenishing. the long term effect of not replacing the particle filter is it will block further and without additive will be unable to carry out a regeneration of the system......the end product will be lack of power and high fuel consumption. Just as a thought ....what do we think the purpose of the high temperature sensor in the exhaust is for? ......maybe to ensure the temperature doesnt become too great and thus inform the injection ecu to stop regeneration functions when exhaust gasses become too high.....under normal conditions exhaust gasses will reach around 450c during regeneration....you wouldnt a want to stand behind it. Quote
Guest HumanTank Posted September 23, 2008 Posted September 23, 2008 The thing that concerns me here is that disconnecting the wire hasnt resolved the problem to a state that you can say you have 'repaired the vehicle'.Having checked out a wiring diagram i'm guessing you have disconnected the downstream exhaust gas high temperature sensor (black 10 way connector pin no 6) .....why this is causing the vehicle to come out of limp home mode i couldnt say. With regard to the blocked particle filter and additive require replenishing. the long term effect of not replacing the particle filter is it will block further and without additive will be unable to carry out a regeneration of the system......the end product will be lack of power and high fuel consumption. Just as a thought ....what do we think the purpose of the high temperature sensor in the exhaust is for? ......maybe to ensure the temperature doesnt become too great and thus inform the injection ecu to stop regeneration functions when exhaust gasses become too high.....under normal conditions exhaust gasses will reach around 450c during regeneration....you wouldnt a want to stand behind it. As i stated (quick fix) and not (repair) you are correct in saying that it hasent repaired the car, anything other than buying new bits and so is not a repair all i am saying is that if you cannot afford the repairs like most people i.s £700+ and they still want to have there car with normal speed and not jumping down the road and snailing up hills this is a dam good reason for doing it. Quote
Guest HumanTank Posted September 23, 2008 Posted September 23, 2008 The thing that concerns me here is that disconnecting the wire hasnt resolved the problem to a state that you can say you have 'repaired the vehicle'.Having checked out a wiring diagram i'm guessing you have disconnected the downstream exhaust gas high temperature sensor (black 10 way connector pin no 6) .....why this is causing the vehicle to come out of limp home mode i couldnt say. With regard to the blocked particle filter and additive require replenishing. the long term effect of not replacing the particle filter is it will block further and without additive will be unable to carry out a regeneration of the system......the end product will be lack of power and high fuel consumption. Just as a thought ....what do we think the purpose of the high temperature sensor in the exhaust is for? ......maybe to ensure the temperature doesnt become too great and thus inform the injection ecu to stop regeneration functions when exhaust gasses become too high.....under normal conditions exhaust gasses will reach around 450c during regeneration....you wouldnt a want to stand behind it. Also yes wires are there for a reason and not just for the pretty colours. I have been driving the car for the past 6 months with lack of power and bunny hoping and percavering with it because of lack of funds to repair the car. So i and loads of other people should be happy that i have dicovered this (quick Fix) so cutting that wire has restored power so i cant see why it shoudnt stay that way for the forseable future. Anyone who carrys out this action please post to see if this has helped. Quote
kfk Posted September 23, 2008 Posted September 23, 2008 My reason for contributing to this is not to 'Knock' your quick fix, but to put forward suggestions as to what you have have done (disconnected) and what the by product might be of the quick fix. It is important that people reading the thread are clear what vehicle it relates to and what the effect of carrying out the mod could be in the longterm. Hopefully the post wil generate some comments from the others that are here. Quote
Guest HumanTank Posted September 23, 2008 Posted September 23, 2008 My reason for contributing to this is not to 'Knock' your quick fix, but to put forward suggestions as to what you have have done (disconnected) and what the by product might be of the quick fix. It is important that people reading the thread are clear what vehicle it relates to and what the effect of carrying out the mod could be in the longterm. Hopefully the post wil generate some comments from the others that are here. Yes you are right to input the facts so anyone who wants to carry it out knows that doing things like this is not recommended but (IT WORKS FOR ME AND I AM HAPPY WITH THE OUTCOME) Quote
Guest HumanTank Posted September 25, 2008 Posted September 25, 2008 Great trick! Have you tried it does it work for you aswell Quote
Guest HumanTank Posted October 2, 2008 Posted October 2, 2008 Under the ECU unit under the bonnet on the passenger side is a cable with a plug which is secured to the bottom of the ECU unit. ALL I DID WAS CUT THE YELLOW WIRE IN HALF and now i have the car back to A1 running you still get the errors on the dash but at least the car runs great now. The engine management light has gone off now and stayed off (This is a couple of weeks since i cut the yellow wire and everthing is running great) Has anybody else tried it if so please post your experience Quote
fujigas Posted October 11, 2008 Posted October 11, 2008 The engine management light has gone off now and stayed off (This is a couple of weeks since i cut the yellow wire and everthing is running great) Has anybody else tried it if so please post your experienceHi, Thanks for the tip, I have just tried it on my 2003 2.2 hdi C8 and it has worked a treat.This is the first time since I bought it back in April that it has been able to rev above 3000 rpm! Even when it was standing and you free reved it, it struggled to hit 4000 rpm. It only had 2 faults, they were the ABS and ESP lights on but the engine light wasn't lit. I thought it was possably a throttle cable problem at first so fitted a new one but that didn't help. then I was convinced it must have been the petentiometer (how ever you spell it!) didn't think it was in limp mode as it still pulled 75 ish in top gear on the motorway at 3000 rpm. But this last 3 weeks I had the anti-pollution message and the engine light come on and my turbo seems to have stopped working seems to be a wastegate solinoid valve problem according to my mates garage diagnostic meter but I ain't got a clue which valve it is as there's that many under the bonnet!Could anybody point me in the right direction with the where abouts of this valve? Anyway other than the turbo now, your tip has worked fine for me, cheers. Quote
Guest HumanTank Posted October 11, 2008 Posted October 11, 2008 Hi, Thanks for the tip, I have just tried it on my 2003 2.2 hdi C8 and it has worked a treat.This is the first time since I bought it back in April that it has been able to rev above 3000 rpm! Even when it was standing and you free reved it, it struggled to hit 4000 rpm. It only had 2 faults, they were the ABS and ESP lights on but the engine light wasn't lit. I thought it was possably a throttle cable problem at first so fitted a new one but that didn't help. then I was convinced it must have been the petentiometer (how ever you spell it!) didn't think it was in limp mode as it still pulled 75 ish in top gear on the motorway at 3000 rpm. But this last 3 weeks I had the anti-pollution message and the engine light come on and my turbo seems to have stopped working seems to be a wastegate solinoid valve problem according to my mates garage diagnostic meter but I ain't got a clue which valve it is as there's that many under the bonnet!Could anybody point me in the right direction with the where abouts of this valve? Anyway other than the turbo now, your tip has worked fine for me, cheers. Glad to be of some help to this frustrating problem Quote
Guest HumanTank Posted November 3, 2008 Posted November 3, 2008 Glad to be of some help to this frustrating problemso far 394 people have read this review but has it helped or not. The feedback would be great Quote
techbod Posted November 4, 2008 Posted November 4, 2008 well personally I find it irresponsible just chopping wires without finding out what they do :unsure:, I wish I could get my 3.18 autodata to work it will have the pin out data for the ECU but sadly it wont work Quote
Guest HumanTank Posted November 4, 2008 Posted November 4, 2008 well personally I find it irresponsible just chopping wires without finding out what they do :unsure:, I wish I could get my 3.18 autodata to work it will have the pin out data for the ECU but sadly it wont workU say irresponsible but if you have read the posts before posting your comments uwould have read that i ran the car with that wire unit unplugged for some time and came to the conclusion that these wires are sensors which i have since tried the rest of the wires to see what they do and i am right sensors ( so your comment irresponsible is posted out of context when i am only giving my experince) THANKYOU Quote
techbod Posted November 4, 2008 Posted November 4, 2008 I did read the other posts and nowhere does it say what the wire does? Citroen/peugeot use numbers on the ends of the wires rather than colour codes so what was the number? ill try to relate it to the xantia or others to see what it does.irresponsible wasn't a personal attack just a judgment so nothing personal if it worked then I would like to know what its used for :unsure: Quote
Guest HumanTank Posted November 4, 2008 Posted November 4, 2008 I did read the other posts and nowhere does it say what the wire does? Citroen/peugeot use numbers on the ends of the wires rather than colour codes so what was the number? ill try to relate it to the xantia or others to see what it does.irresponsible wasn't a personal attack just a judgment so nothing personal if it worked then I would like to know what its used for :unsure:Yes it would be nice to know what all the wires did as i discovered (heat, brake,oil) sensors so the yellow one as some body pointed out being the heat i belive. It would be nice to fix the car properly but at great expencive, so even if this helps out in the short term i think its worth trying. You might find it is worth disconecting some of the other wires to improve performance. What i have done is put femal and male bullet connectors on all the wires out of that plug Quote
techbod Posted November 4, 2008 Posted November 4, 2008 ill try to get the pin-out data and see what the yellow wire does as for the other wire they do a lot more the heat/oil and so on obviously they cover all the sensors on the engine and fuel system but your post is useful as long as it doesn't damage your engine in the long run ;) the wire could be related to the TP sensor so eliminating the speed restrictor now that would be a nice thought :unsure: Quote
Guest HumanTank Posted November 4, 2008 Posted November 4, 2008 ill try to get the pin-out data and see what the yellow wire does as for the other wire they do a lot more the heat/oil and so on obviously they cover all the sensors on the engine and fuel system but your post is useful as long as it doesn't damage your engine in the long run ;) the wire could be related to the TP sensor so eliminating the speed restrictor now that would be a nice thought :rolleyes:Yes damageing the engine we dont want but i have driven 25,000 miles now like it and all seems fine apart from 1 occasion 2 weeks ago when it just lost power going uphill for 5 min then i stopped the car turned ungine off for 5 min then restarted and all was fine. So the outcome is there is still a fault but the car still runs If you could find out what them wires do i would appretiate it Thanks Quote
techbod Posted November 5, 2008 Posted November 5, 2008 been checking a few engine ECUs and the berlingo up to 2004 appears to be the same setup as the C5/8 and a few more HDI but they still only list numbers on the ends of the cables and the wiring diagrams show what the wires do and what sensors are activated ( images to come ) when I have a little time :rolleyes: this is how the wiring diag gives info - injector 1 colour code 1211 pin 2 and 1321 pin 30 ( so its not going to be easy ) but im not giving up ;) . the issue with autodata CD2 is like my car doesn't list much data but if I go back a couple of years its all there so I would assume they don't want to repeat something that hasnt changed now all I need is what the numbers mean to convert them to colours Quote
techbod Posted November 6, 2008 Posted November 6, 2008 http://www.citroen-owners-club.co.uk/citro...?showtopic=7428 as requested :rolleyes: Quote
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.