Bad Cat Converter
Discussion
Engine light came on yesterday, it's something to do with the catalytic converter.
Car drives fine, is it safe to wait until the MOT in a couple of weeks ?
Last job on the car was the exhaust backbox/muffler as it had snapped in two, they dind't replace the whole system, just the rear part of the exhaust. Also a full service around the same time
Car drives fine, is it safe to wait until the MOT in a couple of weeks ?
Last job on the car was the exhaust backbox/muffler as it had snapped in two, they dind't replace the whole system, just the rear part of the exhaust. Also a full service around the same time
At an educated guess I'd say there is an air leak in the exhaust and lambda is picking it up as incomplete burn, could also be that wiring to the lambda wasnt ideally routed and may be damaged when exhaust got hot or vibrated.
If there is an air leak its between the first set of cats at the downpipe and main cat under the car. When your exhaust broke at the backbox, it's possible that without the support it should have been getting, a joint was moving more than it should and has weakened it. This would be the first place I would look. Also car will be running lean with these codes present.
If there is an air leak its between the first set of cats at the downpipe and main cat under the car. When your exhaust broke at the backbox, it's possible that without the support it should have been getting, a joint was moving more than it should and has weakened it. This would be the first place I would look. Also car will be running lean with these codes present.
Edited by Decky_Q on Tuesday 13th September 12:20
OK thanks.
Could this be an expensive job to fix ? I know it's difficult to speculate as code P0420 could be many many things. I'd assume a new cat is dear,
Also. Should I try and drive minimally as possible until seen to in 12 days at the MOT ? ( I have told the garage about the error code and they're going to sort it out before the MOT )
Could this be an expensive job to fix ? I know it's difficult to speculate as code P0420 could be many many things. I'd assume a new cat is dear,
Also. Should I try and drive minimally as possible until seen to in 12 days at the MOT ? ( I have told the garage about the error code and they're going to sort it out before the MOT )
Unless the cat is rattling like marbles in a biscuit tin itll be fine, it's a passive component and has no moving parts to break. As for expense, if it is what I suspect then either tightening a clamp or a bead of weld on the weakened joint will sort the leak so very cheap in the scheme of things. Even if it needs a new lambda sensor it shouldn't be very expensive.
MOT passed with flying colours and the mechanic said the emissions were spot on.
He cleared the light yesterday and said that some cars will give a warning light when the cat is " ageing "
Fast Idle Test
RPM 2814
Lambda actual value was 1.010 ( min limit 0.970 and max limit 1.030 )
CO% Vol actual value was 0.000
Natural Idle Test
RPM 676
CO % Vol actual value was 0.000
There may have been a blockage a couple of weeks back as I had a bad smell in the car for a minute or so which has now ceased.
At no point did I have any symptoms of a bad converter other than that.
He cleared the light yesterday and said that some cars will give a warning light when the cat is " ageing "
Fast Idle Test
RPM 2814
Lambda actual value was 1.010 ( min limit 0.970 and max limit 1.030 )
CO% Vol actual value was 0.000
Natural Idle Test
RPM 676
CO % Vol actual value was 0.000
There may have been a blockage a couple of weeks back as I had a bad smell in the car for a minute or so which has now ceased.
At no point did I have any symptoms of a bad converter other than that.
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