Emisions light & MOT

[Neil G]

Driving down to Cornwall on Friday the emisions light finally made an appearance (Janspeed sports cat fitted)......carried on driving and all seemed okay with no loss of power and good MPG.

I'm not fussed about the light being on but with my MOT due towards the end of the month what I am worried about is failing the emissions test.

Does this light coming on mean that the cat is fooked or the 02 sensor is gone resulting in the fuel/air mix being out?

 

[Neil G]

Anyone?

 

[caymanr26]

no - from what I understand it just means that the emisions level was too high so the light came on - it doesnt actually do anything - its only there to tell you if your cat is fooked but seen as yours isnt its not a problem. ive got my mot next week too with the same light on - it should be ok though. Mine runs no differently with the light on - just wish there was a way to disconnect the light!

 

[Thomss]

Mine came on once before I went decat, it turned out to be a broken sensor on the cat...
Which Ren sorted for me, then I went and got a decat. and it's not been on since.

 

[Neil G]

Has anyone with a sports cat put their car through an mot with this light on...what were the results?

TBH I'm not fussed about the light being on..I think the time to fix that will be when it's time to sell up and I have the original cat to change back to then anyway.

 

[Neil G]

Someone must have some more info on this

 

[Dink]

yeah i put my car through a mot last year with the light on.

passed the emissions with flying colours with a 100 cell sports cat

 

[edde]

To get the light off disconnect the second cat sensor and have the fult log removed.

No needf to have the second sensor connected on the 172's.

172's can pass with a decat but then again they can fail with a cat on emmisions.

 

[Neil G]

yeah i put my car through a mot last year with the light on.

passed the emissions with flying colours with a 100 cell sports cat

That's what I wanted to hear really.....I was just concerned that the light being on would affect the emissions test at the mot.

I hear everyone going on about unplugging the second sensor because 'it doesn't do anything' but whay is it there then.....surely it must have a use?

 

[edde]

That's what I wanted to hear really.....I was just concerned that the light being on would affect the emissions test at the mot.

I hear everyone going on about unplugging the second sensor because 'it doesn't do anything' but whay is it there then.....surely it must have a use?

Its used by the ECU to check the cats working but if there no signal recieved it don't do anything only if it recives a signal that shows the cts fauty will it show it as a fault.

 

[Neil G]

Okay so it looks like the sensor is having a bit of a fit then as the cat can't be faulty....it's a Janspeed sports cat and has only been on the car for six months or so.

Shall I just unplug the sensor and hope for the best come mot time?

 

[caymanr26]

i unplugged my sensor and the light came on 5 mins later - if the fault is cleared will it not come back on edde?

 

[edde]

i unplugged my sensor and the light came on 5 mins later - if the fault is cleared will it not come back on edde?

Shouldn't do.

16V_jon though has to have his connected though or he looses power for some reason but its a Hybrid do his car might have other issues.

 

[Neil G]

Fingers crossed at mot time I suppose

 

[16v_jon]

Shouldn't do.

16V_jon though has to have his connected though or he looses power for some reason but its a Hybrid do his car might have other issues.

ive fixed it now with a transformer and few other bits, its plugged in no light for 400 miles now

 

[the1gardner]

Mine has come on on a totally standard 1.2 16v? Why is this?

 

[edde]

Mine has come on on a totally standard 1.2 16v? Why is this?

Faulty sensor most likly.

 

[JAY172]

i have a k-tec sports cat which is basically a janspeed. sensor plugged in and no lights on and it has passed 2 mots with flying colours