Exhaust emission light on all the time

2001 Vauxhall Agila Problem

The Problem

Avatar Quest Carlsbro
Joined: 4 months ago | Fixes: 8 | Profile
About

The engine fault icon came on intermittently and when it did the temperature gauge stopped working though all was well with the engine.
Now it doesn't come on but the exhaust emission icon is on all the time plus the cooling fan is also on constantly and continues for a few seconds after the engine is switched off.
There are no exhaust leaks, the oil level is correct and the thermostat is working correctly.
The engine appears to be running well.
This vehicle has done 32000 miles and has been serviced regularly though it was standing for a few years before I bought it.
Any thoughts anyone please?


Car Vauxhall Agila
Variant 1.2
Model Year 2001
Category Electrics, ECU, Warnings & Lights

All Vauxhall Agila Problems

Solution

Avatar Quest Carlsbro
Joined: 4 months ago | Fixes: 8 | Profile

For anyone who's had a look at this problem, thanks

I checked out a few sites and one answer that came up was to release the fuel cap and though not quite to my problem, in my case it's worked, these modern electronics are too clever by half!

Solution

Avatar whittingehame
Joined: 9 years ago | Fixes: 11,974 | Profile

No idea how that would rectify faults you had , no rhyme or reason to that " solution "

Solution

Avatar Quest Carlsbro
Joined: 4 months ago | Fixes: 8 | Profile

I've no idea either but I'm not going to complain. I used to be a mechanic so it's got me baffled too

Solution

Avatar Quest Carlsbro
Joined: 4 months ago | Fixes: 8 | Profile

Actually, thinking about it, when I took off the fuel filler cap, there was a sharp release of a partial vacuum, I've noticed this before when the tank is almost empty.
This will mean that the fuel pump has to struggle against it to suck in fuel which will lead to an incorrect fuel/air mix and incorrect reading on the exhaust emissions which will show up as an engine exhaust fault.
I've known this to happen on diesel engines but in that case they just stop and have to be re-bled but it does make sense now.

Solution

Avatar whittingehame
Joined: 9 years ago | Fixes: 11,974 | Profile

The vacuum release is perfectly normal , No disrespect , but with todays fuel systems , and for many years , your theory is bollox .

" This will mean that the fuel pump has to struggle against it to suck in fuel which will lead to an incorrect fuel/air mix and incorrect reading on the exhaust emissions which will show up as an engine exhaust fault."

Solution

Avatar Quest Carlsbro
Joined: 4 months ago | Fixes: 8 | Profile

So what would your explanation be? My 'theory' is quoted in so many words on other sites

Solution

Avatar whittingehame
Joined: 9 years ago | Fixes: 11,974 | Profile

As already stated I have no idea or logical explanation why this occurred .If your theory was correct we would have thousands of cars where the owners run the tanks low having the same problems every day . With a car of that age and that has been standing for a few years , possibilities are endless .I asked another couple of very experienced garage owners if they could explain this but zilch .If the engine light was on you should still be able to retrieve the fault codes using proper diagnostic equipment like tech 2 / 3 .

Solution

Avatar Quest Carlsbro
Joined: 4 months ago | Fixes: 8 | Profile

You make a good point but as it thankfully hasn't reoccurred I haven't been able to do any other checks.
Just prior to resolving the second problem I checked connections of temperature gauges etc and now there is no problem with the gauge not reading and fan being on all the time, none of this makes logical sense but for now it's fine.
Thanks for taking the time anyway

Solution

Avatar whittingehame
Joined: 9 years ago | Fixes: 11,974 | Profile

I have had a few cars in the workshop where , like yours , the fix was totally unexplainable and had us scratching our heads on how it could be . On some the fault returned further down the line , others remained cured .Just a thought , might be worth checking all earthing wires . Some Vauxhalls had problems with an earth wire at ECU , others with engine harness wiring loom . Fingers crossed it remains o.k .

Solution

Avatar Quest Carlsbro
Joined: 4 months ago | Fixes: 8 | Profile

Thanks, if it occurs again, I'll check the earths

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