hi all im new here and my partner has a 2004 1.8 hgt. We have had it for 2 years and it has done 46,000 miles. We bourght it with the engine warning light on and last year it went thorugh it MOT with the light as an advisary, but this year im lead to beleive an illuinated light is a fail? when you start it up it says "engine failure switch off engine". We had it put on a diagnostics machine and it said what the previous owner said that the post cat lamda sensor was faulty. He changed it but still couldnt get the light out. So we put another sensor in to make sure the one he had put in wasnt faulty.

We drove it for about 20 mins and the light came back on. the man at the garage said that we should ask on here as it could be the cat itself ( although he seems to think it has 2) ( maybe someone could confirm this ), a stuck egr valve or something else.

So we was wondering if anyone has come across this before and might be able to help as we dont want to go down the blanket replacement route.

also are the cheepo cats on ebay any good as we may have to look into another one

cheers

Has one cat, 2 lambdas. Could be that the cat has expired (function of the second lambda is to check the cat and first lambda). Generally the lambdas are identical, so you might try exchanging the (probably) OK removed 2nd lambda for the first -- pre cat) position.

Nice cars, but often out of the ken of your average garage. See if there's a FIAT/Alfa (the engine is basically that out of an Alfa 155) independent in your vicinity.

Cats off eBay should be OK, lamdas less certain. Price check with somewhere like CES, though.

the downpipes both have a small silencer or cat on each any ideas what this is? the item number is 330792412829 so you can see. we dont have the old sensor anymore. On ebay their listed as cats Unfortunatly there arnt any independant fiat/alfa specialists round here. so would you be replacing the cat or pre lamda sensor first?

ok sorry to complicate it even more but it has 3 lambda sensors one under the join where the manifold meets the downpipe and then the 2 (post and pre) we spoke about

fingers99 said:

Has one cat, 2 lambdas.

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HGT has 3 lambdas.

I have seen if you put cheap ones on then the car doesnt really like the universal sensors, try get a working original one and see if that helps.

If there is a fault with the sensors, then you may get a readin on your diagnostic reader something like.
Bank 1 sensor 1 faulty (this is the first pre cat sensor)
Bank 1 sensor 2 faulty (this is the 2nd pre cat sensor)
Bank 2 sensor 1 faulty (this is the 3rd sensor after cat)

does the fact that it passed its emisions last year possibly rule anything out. Will it definatly fail its MOT with this light on? am i right in assuming that all the sensors are the same or are they specific?

I'd rule out the cat.

FIAT practice is usually that the lambdas are the same, but with the HGT, who knows.

Main things to watch on these are the oil level -- they all burn oil, so a weekly check is essential, and the cam belt change intervals. If the belt snaps the results are dreadful.

just to update we read the code and it registered P0141 Faulty Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2


can anyone tell me which fuse and where its located that controls the circuit. Just so i can rule out a blown fuse

jamiecoysh said:

just to update we read the code and it registered P0141 Faulty Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2


can anyone tell me which fuse and where its located that controls the circuit. Just so i can rule out a blown fuse

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I very much doubt that a fuse is at fault here
The lambda sensor is at fault that why code is stored on ecu
Unfortunately i dont have personal experience with hgt models but by personal experience when sensors are at fault (lambda, crank, cam, airflow) always replace them with original parts
Hope this helps

the lamba sensors are monitored by the ECU
So NO relay or Fuse to check for the sensor im affraid

you need to find the sensor, check its connected to start with

It could have melted a wire or anything! Who knows?

Ziggy

went back this mornin to have the sensor the garage installed checked and it is working to within spec, they showed me on this fancy piece of gear that showed the voltages across all 3 senders changing as it was reved. They said for us to by a new sensor and put it in and if by some miricle of god it goes out they'll refund us for the money on the sensor. But he's adiment this light wont go out by changing the sensor

so any other ideas?

the exhaust is blowing slightly at the flexy join and the vvt pulley is very noisey making it sound like a diesel

could any of these throw the light on?

jamiecoysh said:

went back this mornin to have the sensor the garage installed checked and it is working to within spec, they showed me on this fancy piece of gear that showed the voltages across all 3 senders changing as it was reved. They said for us to by a new sensor and put it in and if by some miricle of god it goes out they'll refund us for the money on the sensor. But he's adiment this light wont go out by changing the sensor

so any other ideas?

the exhaust is blowing slightly at the flexy join and the vvt pulley is very noisey making it sound like a diesel

could any of these throw the light on?

Click to expand...

:bang::bang::bang:

Yes it can affect the lamba readings
A blowing exhaust means air can escape = Not the correct mixture if it doesn't pass the lamba
OR
Air can enter, messing up the readings

patch the hole and ensure its sealed

remember NO exhaust paste above (pre) or within a small section after it

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The knocking engine sounds like the variator is probably ready for changing
the variator IIRC, uses the oil pressure to vary the timing of the valves, to gain better scavening and better bang = more Power-uh!

So sounds like it needs a little tlc, but im going on what you've said been spot on and me understanding it correctly

Ziggy

ok we'll look into getting the front section of the exhaust changed. What will happen if the variator fails?

Is this warning light on an advisory or fail?

Without the variator working properly it'll make a lot of noise, drink more fuel, be more likely to fail emissions, be unpleasant at low revs.

This year, my best guess is it'll fail with the ECU light on.

Sad to see a nice engine being treated so badly.

want i ment was would it fail for the light being on even tho the emmisions are fine ( like last year )

sadly it is my partners car and get fixed as and when she sees fit, It is in very good condition every thing else works as it should low milage been lowered 60/40 ( previous owner ) and we have just bourt black 17" fiat 500 abarth wheels and it looks quite nice she thraches the f*c! out of it everywhere. I think i might have it limited to 69 mph like my van

This year a lot of stuff has been tightened up around the edges which is why I think "maybe". After all, it's an ECU warning light, and one of the main functions of the ECU is to control emissions. If in doubt, ask your MOT man.