Fault in exhaust system

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juliang71
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Joined: Thu Mar 21, 2024 10:02 pm

Fault in exhaust system

Post by juliang71 »

Evening, after a bit of advice. I've recently bought a 2019 Caddy Maxi Life 2.0l diesel DSG and after a little over 100 miles I've got the yellow "Fault in exhaust system" light come on. It looks like an engine management type light, but after looking in the handbook it's definitely the exhaust one.

I'll go back to the dealer after the Easter break but I'm curious to know if anyone has seen this and better still might be able to suggest what's at fault.

Thanks.
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Javito
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Joined: Sat Feb 18, 2023 12:56 pm
Engine size/power: 1.6 CR TDI (75bhp)

Re: Fault in exhaust system

Post by Javito »

It's this the light you see?

Image

If so it's the DPF that hasn't been able to regenerate properly.

Warm the engine up and do a good half hour of motorway driving. Doesn't need to be very fast, just keep the rpms over 2000.
When the regeneration starts you'll notice it'll idle at higher rpms. Just under 1000. It will go back to normal once the regen is done.

If that doesn't fix it then there might be another issue.
juliang71
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Re: Fault in exhaust system

Post by juliang71 »

Apologies I couldn't figure out how to upload an image of what I see, but here it is. So this is what appeared and in the handbook it just says "Fault in exhaust system". And directs me to page 212 ... which doesn't mention the above at all.

As I was already out when this came on I did drive home with it on and the car felt exactly as before, no limp mode or other warnings seen on the dash.

Image
Andrew5
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Engine size/power: 2.0 CR TDI (108bhp)
Location: England

Re: Fault in exhaust system

Post by Andrew5 »

Could be a nox sensor fault think that’s the light I got seems to be common on these
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Javito
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Joined: Sat Feb 18, 2023 12:56 pm
Engine size/power: 1.6 CR TDI (75bhp)

Re: Fault in exhaust system

Post by Javito »

Correct me if I'm wrong but to me that seems like a check engine light. Which means there's a malfunction. You'll need a diagnostics tool like vcds, obdeleven, etc to read the stored trouble code/s.
juliang71
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Re: Fault in exhaust system

Post by juliang71 »

Definitely not a check engine light, although at first look you would think so. I've seen this before on other vehicles ... had it on my 06 plate runaround VX Corsa.

It's something exhaust related as per handbook, best guess as mentioned above is a NOX sensor. Waiting to get it back to the garage for them to check it.
juliang71
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Posts: 32
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Re: Fault in exhaust system

Post by juliang71 »

So in the end I think the light on the dashboard was a bit misleading. I took the car to my usual garage of choice for a full vehicle health check and they found a glow plug that was faulty or failing or some such. With that replaced and the fault cleared I've done several hundred miles without issue :D
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