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General => The garage => Diagnostics - VagCom / VCDS => Topic started by: Agreeable Slick on 26 January 2010, 20:28
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Ok guys, this is really getting my goat now.
Since xmas last year the g/f car has been having problems, first the exhaust broke. Got it replaced, then the emissions system has been playing up ever since.
Replaced the CAT, replaced the pre and post cat sensors. (rear is NGK, front is Bosch)
However, no matter what we have done this code keeps reappearing.
16804 - Catalyst System; Bank 1: Efficiency Below Threshold
P0420 - 35-00
I clear it, and roughly 400-500 miles later the ECU light comes back on and repeats the code. It's doing my head in.
Can anyone help at all? I've looked at the internet help for all of it and it's not helping.
Toph? Can you and the R-Tech guys do an ECU flash on it? Or take out one of the sensors from the ECU?
Cheers everyone.
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I've heard of this problem before, what make was the replacement cat?
If it is a copy part, sometimes it doesn't work as efficiently as the original.
The pre and post cat lambda sensors pick up on this.
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was it 100% the right sensors also?
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It is a pattern cat, seeing as a genuine article is about £600 notes. :shocked:
Yep, we went through the process of buying every sensor variety that was available and made sure it was the right ones.
It just seems strange as when we originally replaced the CAT it was fine for 9 months. (Changed in FEB last year, this has been playing up again since NOV last year)
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Its a regular problem, apparently according to car mechanics magazine.
The pattern cat is not reducing the carbon monoxide enough.
You need to get another cat, or just ignore the engine management light.
How is it testing for emissions on the MOT?
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Flew through the MOT with no problems. Might see if I can pick up a cheap second hand one and see if that cures the problem. Do you or anyone else know if there is a way of altering the values it measures against? Perhaps opening up the tolerances could be done
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I don't know if you can alter the values to be honest.
A second hand unit could be a choice, however if the emissions are fine, you could just ignore the light.
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I'd say the cat has had it - pattern ones only last a few months in my experience. What year/engine is it? We can alter the map to change the o2 threshold so the light won't come on but the initial issue will still be there.
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it's a 52 Ibiza 1.2 3cylinder. Think the engine code is 6L? We are going for an exchange on the Bosch bit but I'm beginning to sway towards cat aswell. Should be a free exchange aswell
Toph: how simple and how much should we need it?