Peugeot 308 depollution system faulty
The car is a 1.6VTi which has done 54000 miles, mostly on the motorway at 700 miles a week.
Had the depollution system faulty light come up three weeks ago. The car was due a service & MOT but it had cleared by the time it went in. No faults were found and it passed the MOT emission test.
Fault came back a few days later whilst town driving but again cleared after about 200 miles of motorway driving.
It has now come back a third time, again whilst town driving.
I have tried different filling stations thinking it may be supermarket fuel (rumour has it that it is inferior quality) but the fault remains.
Any help would be much appreciated.
The fuel may well be not the problem. The fuel is not 'inferior', it just does not have the amount of additives that the big name brands have. The depollution light is also an indicator of a fault in the engine management system and a diagnostic check should find this for you.
Originally Posted by Sootblower69
It is also absolutely essential that the correct grade and type of engine oil is used in cars with engines such as yours. The wrong grade, type or one with a high ash content can all affect these engines.
Thans for that. "Inferior" was the wrong choice of words for supermarket fuel. I have used it for many years with no problem, it wa sjust a thought. I am using fully synthetic oil, grade as per the hand book. There was nothing on the diagnostic check at the service. Not sure if a main dealer, or other garage, could "look" back through the history of the management system. This is usual in industrial control systems that I work with but not sure for cars.
It much depends on what the equipment the garage used was. Sometimes a fault can be logged in the EOBD system that all new cars have but not in the manufacturer's side and vice versa.
I use an all round tool and very often it does not trace a fault but then the dealer tools that I also use can. The trouble is it keeps correcting itself once you get on the motorway.
On Citroen/Peugeot cars, there is a history log of when any codes are cleared. When you use the dealer tool you have to enter the mileage before erasing codes but the log remains stored. However if you use an aftermarket tool, you don't always have to do this so nothing is logged. It really is down to how good the tool is and the person operating it. A good diagnostic tech will know what the parameters are for each sensor and be able to spot one that may be just out of spec even though no codes are logged. If you can do a diagnostic check with the system warning on then you have a good chance of finding the problem.
I'd hazard a guess that an oxygen (lambda) sensor is failing, possibly the heater circuit, and that is why it only happens in town when the exhaust is not so hot.
Last edited by Hometune; 22-11-11 at 17:13.
Very many thanks for that. Some really useful advice. I will probably have a go at putting it into the main dealer if the fault stays up lomg enough. Thanks once again.
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