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Robert, UK Qualified Car Technician
Category: Car
Satisfied Customers: 4708
Experience:  Fully qualified / self employed garage technician in the UK
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Hi,my engine managment light wont go off,changed exhaust (second

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Hi,my engine managment light wont go off,changed exhaust (second hand ) new sensor,air filter,full service. The light goes off when reset but comes back on after a few miles my mechanic says car is fine and not to worry as its just gone through an mot with no problem. HELP PLEASE.


Hopefully i can help..

Whats Fault Codes are being logged when scanned?

What sensor exactly was changed?

Customer: replied 3 years ago.

Hi Robert,i dont known what codes were logged the sensor on the catalictic converter was changed.

Hi..there thanks for your responce..

Ok..Normally the only way to determine exactly whats going wrong or what the ecu is picking up on as need to know what faults codes are being listed - i dont really agree with just ignoring to be honest,if there was nothing worng with the engine then the light wouldnt come on - the engine light comes up for reason and there is sooo many reasons for it to come up its would be difficult without some sort of code to say for sure what you'd need to check next - its most likely maybe due to sensor running out spec/faulty which in turn can can upset fuel/air ratios - a wiring problem..have they checked the connectors around the engine bay aswell as the lambda sensor connectors for problems/ecu harness plug basically checking all the electrical plug connectors for corrosion issues etc,inspect the mass air flow meter sensor inside and clean with mas air flow cleaner if..but the key is to find ut what these codes are being listed when the EML comes up this in turn give a better idea which area to investigate rather than just throw parts on it and hope if solves the problem..You can also try putting the eml out by disconnecting the negative terminal from the battery for about 15mins..and that can normally reset it..but like i say you need to know what these codes are or consider trying somewhere else whom may be able to dig a bit deeper into the fault/proper diagnostic on it..I do hope this helps

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Customer: replied 3 years ago.

Hi,thanks for your reply as I work away from home I will have to wait till weekend and I will ask the mechanic who worked on the car.

Customer: replied 3 years ago.

Hi Robert all is sorted I replaced back box on exhaust disconnected battery for 15mins lo and behold all is good with light marvellous !! Thanks for your help.


Many thanks for keeping updated on your progress..and glad its all sorted out for you!..But if you ever need to ask anything else or need advice as such then just let me know and i'll be happy to help as best i can..Regards Robert