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Discussion Starter · #1 ·
No, not really guys, I've managed to use the code reader to put the E. M. light out after a few weeks. I simply could not bloody reach the port. But once I managed I only found the one code named P0170. Fuel trim error. So I don't think its anything to worry about.

Any thought guys, how much that might have cost in a garage, or what the could have diagnosed to repair even? I know the Citroen Garage charge £66 to use their diagnostic tool last year, before the MG.
 

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In the Garage
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MGTF Lambda Sensor part number MHK100840, aftermarket units can be had on eBay for about £15 but I wouldn’t buy a lambda for that amount as I can’t see it lasting. Better ones can be had for £40 to £70. For example, http://mgmanialtd.com/index.php?id_product=737&controller=product

In theory it is a DIY job but the old sensor is unlikely to come out of the exhaust without a fight.

Does the code reader have a live data function, if so it would be good to see the lambda voltages and any other data coming from the fuel and emissions system?
 

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Discussion Starter · #6 ·
Hi Chris. No sadly not, but Peter has one of the all singing, dancing ones, so maybe I'll ask him to do a test for me? What problems would the car through up, if the Lambda was at fault, and could it have been all the battery problems I had, taking it off and on, running it down and such? Or am I grasping at straws Chris?
 

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Discussion Starter · #7 ·
Interestingly my garage have said don't worry too much. It could be a number of things, like even under use, and that could be right as a number of member have said their light goes off after running a few miles, or even a few days, interesting.
 

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2002 MG TF VE51FTF
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I'm just starting to get my head round ECU's, sensors, SRS etc and finding it rather challenging to say the least.
When my MIL came on I read up and I seem to have a different conclusion to Roverlike but no offence is intended just clarity.
As I understand the two sensor set up the first (pre CAT) sensor reports to the ECU on combustion ie too rich too weak and the ECU adjusts engine settings accordingly, the second sensor (post CAT) is reporting on the CAT efficiency presumably (I'm still learning) by comparing its reading with sensor one?
It seems that sensor two causes a lot of MIL lights when nothing is apparently wrong and you can fit a bypass kit (legal?) to stop the light coming on, of course there maybe a real problem you are now unaware of until MOT time.
This now raises the issue that you take the car for an MOT and they curtail the test with a fail because your MIL is on (automatic failure) but the car could well be within the emissions parameters, weird!
If my understanding is wrong please feel free to shoot me down as otherwise I will never learn.
 

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P0170 code means Fuel Trim Malfunction Bank 1. Bank 1 means first lambda (oxygen) sensor. Bank 2 would be second post cat lambda (oxygen) sensor.
Usualy if second (post cat) lambda (oxygen) sensor is faulty you would get P0420.

This would be the first thing to look. It might not be straight forward and replacement of sensor solves the thing, but something else influence this error, but in that case you would expect some other errors as well or behaviour of engine would indicate differently.
 

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Just pulled this off the WEB more than one mention all stating the same which is why I came to my conclusions, I always presumed it was to cater for V engines with a separate O2 sensor for each bank. OBD11 was first made mandatory in California where V8's were/are common so assumed that's why it was standard. If it means something different in Europe where would I find this information.

Bank 1 and bank 2 simply refer to either side of the engine. ... Most commonly, bank 1 houses the front most cylinder on the engine cylinder 1, and bank 2 is the opposite side of the engine. Check out the pics below to see several different configurations.
 

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You mostly described how two sensors work correctly. However you cannot work out the cause of DTC from OBD2 code list on american cars or european cars as general rule.
You need to see how these behave on MG-Rover cars. Every manufacturer implemented OBD2 codes but in the same time errors will appear for different reasons from manufacturer to manufacturer neverthless the standard, because failures cannot be standardized.
What you need is to read these forums, because from them you can learn a lot and how things are solved when particular error occure. Conclusions come from experiance rather then standards.
 

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Bank 1 and bank 2 simply refer to either side of the engine. ... Most commonly, bank 1 houses the front most cylinder on the engine cylinder 1, and bank 2 is the opposite side of the engine. Check out the pics below to see several different configurations.
This is basically correct - but is rather more to do with the number of exhaust outlets, with bank 1 referring to the outlet from the front/primary side of the engine and Bank 2 referring to the other. Thus where there are both pre and post catalyst Lambda sensors, you will have Bank 1-Sensor 1, and Bank 1-Sensor 2; and on the other exhaust outlet will be Bank 2-Sensor 1 and Bank 2-Sensor 2.

Just to confuse, some V engines have the two exhaust systems merge into one further down the line, so you may have both Bank 1-Sensor 1 and Bank 2-Sensor 2, but only have a single post-cat sensor which is then just referred to as Bank 1-Sensor 2.

On our more 'normal' single in-line engines, the sensors are designated 'Bank 1, Sensor 1' (pre-cat) and Bank 1, Sensor 2 (post cat).

The generic OBD codes will give you a general idea of where the fault lies, but each manufacturer has a slightly differing specific fault description for each code, so you would need to know the specific manufacturer definitions for each OBD code to get an exact interpretation. These details can be difficult to get hold of unless you are an official service agent for the manufacturer, which is where researching forums such as this one are invaluable in finding out what others have needed to do to resolve the issue.

To follow on from Roverlike's post; forums are a massive repository of valuable information, all easily found from the wider internet and easily searchable to find the information you need. This is also the reason why the opaque nature and impossibility of searching makes the likes of facebook so utterly useless, and probably why so much of the supposed 'advice' handed out over there turns out to be either misleading, incorrect, irrelevant or dangerous (or indeed, any combination of those!).

To answer Richard Barrett's earlier question, P0170 is always associated with a Lambda sensor, and generally indicates a fault with the sensor itself rather than a problem with fueling/combustion. I think it unlikely that E10 petrol has caused any issues (especially as it is only the case that E10 is permitted to have up to 10% ethanol content. The 10% is not mandatory, so I would think it quite possible that a great deal of the petrol currently sold as E10 actually has a much lower ethanol content than that - the oil companies will only use ethanol as and when it is economical to do so, and as several of the fedstock crops used for bio-ethanol production are currently fairly highly priced on world markets, I don't imagine bio-ethanol is as attractive as it once was).
 

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2002 MG TF VE51FTF
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Man in the car, I've read you post many times and have now grasped your explanation, you gave a good explanation of a very complicated subject (on just 2 sensors) but my brain was in neutral.
I have purchased pscan and want to learn as much as I can (go away dementia not yet) as the car is SORN'd and wrapped up I've yet to try it. Can you advise me of any books articles etc that would help give me a grounding in the subject prior to connecting when I suspect I will say AND so what?.
I'm looking for books manuals that will say in normal operating conditions sensor ? should give a voltage range reading of ? but take on board your comment about service departments manufactures not being free with the info concerned. Is it a case of taking a screenshot/vid of what I have and posting "this is mine what's yours like" which sounds a bit hit and miss to me.
I will add that I have and have read Roger Parkers F/TF restoration guide that touches very lightly on the subject but would welcome suggestions from anyone versed in these black arts. How strange that at school/college I never said "please sir what shall I read next" and now I'm pleading.
 

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Rover Lifestyle
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This is basically correct - but is rather more to do with the number of exhaust outlets, with bank 1 referring to the outlet from the front/primary side of the engine and Bank 2 referring to the other. Thus where there are both pre and post catalyst Lambda sensors, you will have Bank 1-Sensor 1, and Bank 1-Sensor 2; and on the other exhaust outlet will be Bank 2-Sensor 1 and Bank 2-Sensor 2.

Just to confuse, some V engines have the two exhaust systems merge into one further down the line, so you may have both Bank 1-Sensor 1 and Bank 2-Sensor 2, but only have a single post-cat sensor which is then just referred to as Bank 1-Sensor 2.

On our more 'normal' single in-line engines, the sensors are designated 'Bank 1, Sensor 1' (pre-cat) and Bank 1, Sensor 2 (post cat).

The generic OBD codes will give you a general idea of where the fault lies, but each manufacturer has a slightly differing specific fault description for each code, so you would need to know the specific manufacturer definitions for each OBD code to get an exact interpretation. These details can be difficult to get hold of unless you are an official service agent for the manufacturer, which is where researching forums such as this one are invaluable in finding out what others have needed to do to resolve the issue.

To follow on from Roverlike's post; forums are a massive repository of valuable information, all easily found from the wider internet and easily searchable to find the information you need. This is also the reason why the opaque nature and impossibility of searching makes the likes of facebook so utterly useless, and probably why so much of the supposed 'advice' handed out over there turns out to be either misleading, incorrect, irrelevant or dangerous (or indeed, any combination of those!).

To answer Richard Barrett's earlier question, P0170 is always associated with a Lambda sensor, and generally indicates a fault with the sensor itself rather than a problem with fueling/combustion. I think it unlikely that E10 petrol has caused any issues (especially as it is only the case that E10 is permitted to have up to 10% ethanol content. The 10% is not mandatory, so I would think it quite possible that a great deal of the petrol currently sold as E10 actually has a much lower ethanol content than that - the oil companies will only use ethanol as and when it is economical to do so, and as several of the fedstock crops used for bio-ethanol production are currently fairly highly priced on world markets, I don't imagine bio-ethanol is as attractive as it once was).
Thanks. This post refreshed my memory around Bank 2 and sensors numbering which I obviously forgot.
 

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No sweat your lucky to have knowledge to misplace, I'm still trying to acquire some.

Having a breather from electrickery and making a sat nav mount for the centre vents, MDF, plastic, bits of metal I can understand. If it comes out well I'll post a pic if it doesn't I'll disconnect the interior lights
 
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