Fault Codes - P1160 turbo boost code

Does anyone have the definitive list of C3 fault codes and the official citroen description?, I would imagine there are thousands and I'm getting sick of looking them up online. Plus, what part of the system would send the P1160 turbo boost code? the ECU after calculating the value of all the sensors?, or one in particular that may or may not be faulty. I don't think there is a boost problem so would rather change the relevant sensor than half the engine in vain. Could this code be sent as a result of a small exhaust leak after the flexible joint causing an exhaust pressure drop? but then where is the sensor for exhaust pressure? or could this cause a increase in boost due to the lack of resistance in the system causing an increase in exhaust flow rate thereby boosting the boost beyond acceptable levels as detected by the inlet pressure sensor? So many questions and so little time!!!!!!!!!

Hello Bill. There isn't a list as such because the same code can mean different things depending on the parts fitted to the car. Some codes are so specific to a particular setup up you will find a generic code reader fails to pick them up.

Citroens answer in the workshops a few years ago was the Lexia tool - available to DIY mechanics - here is also programmed to show the tests required to diagnose some faults and make a diagnosis from those tests.


We have a topic covering lexia and diagbox for the C3 diagnosis that has some useful information regarding installing on Windows.


I think your first step would be to ensure you have the right description for P1160 with your particular engine, engine ECU and all the various ancillaries.



as for the second part of your question, which may or may not be useful to you is - the turbo charger boost pressure is generated in the inlet side of the engine and not the exhaust. There is no boost, or boost sensor in the exhaust, its the inlet side has 'boost' (to force the air into the engine). Not all engines have monitoring of the inlet manifold pressure but some do, its all depends on your particular set-up.

It would be worth checking that the EGR system is working as intended as this interfaces directly with the inlet manifold where the turbo pressure is stored.

Ok C3driver52, thanks for the advice on code readers, I have the basic scan tool (£15 on ebay) and it gives me the numbers OK but not the meanings or origin of them. Presumably a dealer could supply me with the vehicle specific meaning of the codes if supplied with the VIN? or is beyond anyone to say without actually having the vehicle, VIN and code reader all at the same place at the same time? thereby maximising their profits by making it impossible to fix otherwise? and yes I am very cynical!!

On the second issue, the P1160 turbo boost fault, is the fault registered on both -ve and +ve values when compared to normal? because I seriously can't imagine a lack of boost being the problem, it is pulling like a train and from lower revs than the old engine used too, and a slight exhaust leak would theoretically increase the flow rate and spin the Turbo faster

Hi Bill

bill sutton wrote: I have the basic scan tool (£15 on ebay) and it gives me the numbers OK but not the meanings

So, you only have P1160 and no interpretation of that for a Citroen C3 (with unknown engine, ecu, production date, serial number...)

How can you know that your P1160 is actually a turbo boost code, at least be so sure to start investigating a problem that has no symptoms indicating a turbo boost problem?

bill sutton wrote:Presumably a dealer could supply me with the vehicle specific meaning of the codes if supplied with the VIN? or is beyond anyone to say without actually having the vehicle, VIN and code reader all at the same place at the same time?

They will need the car, and can then plug in their code reader, give the production date of the car. From this the code reader can get the vin, engine ECU type and importantly access the database of which parts are fitted to that car and what the faults codes that they give are referring to. Its just a physically easier to have the car to plug the reader into.

bill sutton wrote: I have the basic scan tool (£15 on ebay) and it gives me the numbers OK

The basic tool can only give codes that it can access in the ECU. If there are other codes stored, that it can't see, it won't show them and you will never know.

bill sutton wrote:thereby maximising their profits by making it impossible to fix otherwise?

Well, the answer that others have found is to get your very own lexia tool or find someone who has one. You need a laptop or pc near the car to run it, but an old one will do well. This way you can use it multiple times, do 'before and after' readings and follow the instructions for diagnosing faults and activating tests for a one off cost. What you don't get is the expertise of a citroen technician or the knowledge base of citroens diagnostic fault team in the UK and France.

I don't think citroen make things complicated to make them difficult to fix, its just that things are complicated and because of that, they can take time and skill to fix.

bill sutton wrote:On the second issue, the 1160 turbo boost fault,

If, that is really the description?

bill sutton wrote:is the fault registered on both -ve and +ve values when compared to normal?

Consider this, you are dealing with a computer running a software program. This is the engine ECU. It takes in signals from sensors, and sends signals to actuators. The program can compare sensors, compare sensor readings to a stored 'map' of expected readings referenced by other sensors, compare reading before and after an activation to ensure the activation has been successful. It then may, or may not, depending on programming, store a fault code for a particular failure of expectation.

The thing with those 'P' error codes is that they don't tell you which part to change. It comes as a great disappointment to many who want a quick fix. What the codes do is tell you what the computer has detected as 'wrong' or 'unexpected'. The cause has to be found before the problem can be fixed. Understanding the system, interpreting the fault description and applying it to the system functions can lead you on a path to follow of testing and checking to find the faulty component.

This can sometimes be short-cut with 'common faults' and can save time on faults on most cars, but not always. It may be a common occurrence of Pxxxx = yyyy is faulty, but not always.

bill sutton wrote:and a slight exhaust leak would theoretically increase the flow rate and spin the Turbo faster

Excess boost pressure regulation is provided by the wastegate. If the wastegate is working, you won't get excessive boost.

How can you know that your P1160 is actually a turbo boost code, at least be so sure to start investigating a problem that has no symptoms indicating a turbo boost problem?

Well, it's like this, what else would you suggest I investigate other than the fault listed? I have to start somewhere. I can drive to the nearest dealers and pay £65/hr for their "best guess" or i can try, with the help of any informed and experienced owners who have encountered and possibly cured similar faults, to do better.

I don't think citroen make things complicated to make them difficult to fix, its just that things are complicated and because of that, they can take time and skill to fix.

I do not share your faith, It is in their interests to make a vehicle which only they can fix, to the tune of £65.hr, and if they fail to solve the problem 10hrs down the line, they're £650 better of and you get the scrap value if your lucky, which is immoral but justifiable if, and only if, they know any more than we do about the problem presented. but I don't think a few technical seminars and an embroidered boiler suit is any substitute for the sum total of all combined experiences of all the C3 owners, and if at the end of the day, I have to eat humble pie then so be it, at least I'll know it was money well spent and that I really wasn't being robbed after all.

Well thats the plan anyway.

I suspect there is very little wrong with my "new" engine, and that the fault codes are being thrown up erroneously because I've had the audacity to fit another engine without paying Citroen a fortune for the priveledge.
As for the twisted perversity of their "one way only" engineering and the lengths they go to, to prevent people from not needing their services, I could bore you at length, as they have me!!

I can confirm that the ecu is Delphi C6 and that P1160 is still recurrent after cancellation, but doesn't seem bothered if I drive carefully, avoiding excessive acceleration or foot down. Did a temporary fix on the exhaust leak and tightened all the inlet hoses and nothing seems to change its mind.
to add insult to injury, on two occasions the MIL has gone out on starting (so presumably no fault for the previous four outings?) but then came on shortly afterwards with a P1160 again.

in terms of the complexity of the systems involved, it is my understanding that the OBD protocol was introduced to provide a degree of conformity between manufacturers, and on my "basic" code reader, the 8 pages of possible data sets provided for, would probably have enabled me to diagnose something. The fact is Citroen have chosen to make their codes "manufacturer specific" to prevent people accessing this information which the protocol was intended to make available, This was in response to EU legislation intended to free up the lucrative but restrictive franchise structure and enable non dealer garages to undertake repairs under warranty etc. Now we couldn't have that could we!

Did you check (or change) the MAP Sensor

The picture is wrong in the one above, but its the right part, like this one on Euro Car Parts website.

After various mysterious "happenings" like engine cut outs accompanied by power steering failure, it threw up a P0336 P0337 relating to crankshaft position sensor, which I remembered was cracked when I came to reconnect the wiring harness. Thought I should have changed it then but as I'd already got the cambelt cover, alternator belt and pulley back on by then i took the chance.
Anyhow, I swapped it for the one off the old engine and "bobs my uncle" running fine no fault codes, no turbo boost issues, sorted! Well for now at least. Why a faulty crank sensor should disable the power steering is beyond me, any ideas?

Spoke too soon, light came back on after three days P1160/P1351 as usual. The MAP sensor is from the old engine so proven ok, but the manifold pressure seems to be a constant 96kpa up until about 2500 revs when it starts to to climb. The turbo however is working from about 1600 revs, so why no increase in pressure until 2500? any ideas?