Technical Check engine light at speed after cam belt change

[KS95]

Got my first car a few months ago, a 2012 1.2L Fiat 500. It belonged to a family member and is in really good condition with less than 48k on the clock

We had no evidence of when the cam belt was last changed so got that done on Saturday

On the way home from the garage I get "start stop unavailable", warning triangle, and intermittent check engine light once I hit 65-70mph. Take it back to the garage, he says the code is a cylinder misfire, clears them and sends me away. People online have been telling me it needs a phonic wheel reset so I call the garage and he basically tells me to do one, that that's specialist dealer software, and he wasn't going to do it but he could fully strip the engine. I'm not willing to go back to him and pay him for every little problem I'm sure he'll find.

Saw something about a manual phonic reset (warm engine, rev to 5k for 3 seconds then idle, repeat three times) and did that but still getting warning lights at high speed.

It seems to be driving fine. A friend came with me for a short drive and said it's not misfiring, and I'd know if it was. Today I paused my music before I hit 65 so hear if there was a sound change but nothing. I don't believe there's a loss of power.

What are my next steps? I'm worried if there's a timing issue it's damaging the car and I'm angry there was nothing wrong with it until the cam belt was done and don't want to chuck even more money at it at a second garage

(Avoid third avenue autos in Bletchley)

 

[steveras57]

phonic wheel reset best done via MES software might be worth looking on the register to see if anyone near you who might help check for fault codes and do the reset!.

 

[KS95]

Thanks for your reply

Do you think it sounds like a phonic wheel? Are cylinder misfiring errors common when the phonic wheel needs doing?

Thanks for that link. Nearest is about 40 mins away. Is a local specialist likely to charge a lot for this?

 

[steveras57]

generally most mes members will help for free!(but it nice to offer petrol money if they have to travel)
the phonic wheel relearn in effect synchronises the timing between the cam, crank etc and if its wrong misfires are common!

 

[KS95]

It may well be worth me hopping on the motorway then. I appreciate your input, cheers

 

[Pugglt Auld Jock]

Got my first car a few months ago, a 2012 1.2L Fiat 500. It belonged to a family member and is in really good condition with less than 48k on the clock

We had no evidence of when the cam belt was last changed so got that done on Saturday

On the way home from the garage I get "start stop unavailable", warning triangle, and intermittent check engine light once I hit 65-70mph. Take it back to the garage, he says the code is a cylinder misfire, clears them and sends me away. People online have been telling me it needs a phonic wheel reset so I call the garage and he basically tells me to do one, that that's specialist dealer software, and he wasn't going to do it but he could fully strip the engine. I'm not willing to go back to him and pay him for every little problem I'm sure he'll find.

Saw something about a manual phonic reset (warm engine, rev to 5k for 3 seconds then idle, repeat three times) and did that but still getting warning lights at high speed.

It seems to be driving fine. A friend came with me for a short drive and said it's not misfiring, and I'd know if it was. Today I paused my music before I hit 65 so hear if there was a sound change but nothing. I don't believe there's a loss of power.

What are my next steps? I'm worried if there's a timing issue it's damaging the car and I'm angry there was nothing wrong with it until the cam belt was done and don't want to chuck even more money at it at a second garage

(Avoid third avenue autos in Bletchley)

What you're describing here is absolutely text book example of the symptoms when a Phonic Wheel Relearn is needed. Typically, following a cam (timing) belt replacement the Check Engine Light will come on the first time the car is taken for a "proper" drive (ie. not just "round the block") but there are no obvious signs of a miss fire and the car drives well. When the fault codes (DTCs) are checked it's found a misfire code is logged. It logs these codes because it's the nearest specific code it has access to which fits what it is experiencing - I don't believe it has a specific fault code to indicate a relearn is needed. So, under these specific circumstances, although fault codes for a misfire are logged the car needs a relearn performed.

The "revving up" procedure you describe above is part of the procedure but the ECU has to be prepared to receive new data first and that preparation can only be done with a suitable tool - Like the dealer computer or MultiEcuScan (MES) which many folk on here have. There's a thread listing those who are prepared to help with theirs. Most small concerns, unless they specialise in Fiats, will not have the necessary equipment.

I'm not quite so sure about the stop/start issue but I think that may well just go away when the relearn is carried out. The good news is, as long as all that's "wrong" is that a relearn is needed, you're not going to damage the engine by ignoring that CEL However It shouldn't be left indefinitely because you now won't know if it's trying to alert you to some other more serious fault.

So, what to do now? Well, you say the car is performing normally? It is relatively easy to mistime the belt when doing these and end up with the belt fitted one tooth out. However this will result in a loss of performance so you'd be noticing this. Let's assume then that the belt has been fitted correctly. All that is now needed is for the car to be connected, Via the OBD port, with a suitable diagnostic scanner (It would be my MES if I were doing it) and for the complete Relearn procedure carried out. It's not a lengthy procedure. Personally, I would expect this to be part of the job of fitting the new belt but if the garage doesn't have equipment which can do it then it's very difficult because they'll have to take it to the main dealer and that will cost them and they are unlikely to carry the cost of that themselves. I know our local main dealer automatically does a relearn every time a belt is fitted, they don't wait to see if the customer comes back with the light on. On the other hand I know our local wee FIAT indy doesn't automatically do the relearn but takes the car out for a good 15 minute drive to see if the light is coming on or not. If it stays off they don't "interfere" with it.

By the way. Why does this happen? Well, the camshaft has a sensor which picks up on the camshaft pulley timing mark and the crankshaft has a sensor which picks up on the crankshaft pulley timing mark. The ECU, during the Phonic wheel learning process, learns positions of these two sensor signals in relation to each other as the shafts rotate and stores that info. When a new belt is fitted this data changes very slightly due to the new belt ever so slightly altering the relative positions of the two shafts then, when the engine runs, the ECU is not seeing the data (angular relationship between the two shafts) which it has stored in it's memory so thinks, OOPS, something wrong here, so it logs the fault code (it doesn't know it's a misleading code) and lights the CEL to alert you. Carrying out the relearn tells it to accept the new pulley positions as correct and once you've done it you just clear the stored code/codes and all is well. The Phonic wheel, by the way, is the large toothed fan belt pulley on the crankshaft.

 

[KS95]

This is reassuring and very helpful, thank you for taking the time to respond. As I mentioned it's my first car and I've been feeling quite stressed about all of this! I checked the map and the closest user with the software is a good 40 minutes away but there is a well reviewed garage near me that state they are Fiat/Alfa specialists so I'll ring and ask for a quote on a phonic reset.

 

[Pugglt Auld Jock]

This is reassuring and very helpful, thank you for taking the time to respond. As I mentioned it's my first car and I've been feeling quite stressed about all of this! I checked the map and the closest user with the software is a good 40 minutes away but there is a well reviewed garage near me that state they are Fiat/Alfa specialists so I'll ring and ask for a quote on a phonic reset.

That sounds like a very good idea as they may be prepared to quickly check the belt has been properly fitted too. As FIAT/Alfa specialists not only will they have the correct tooling but they'll also know the cars intimately so will be able to pick up on anything which hasn't been done quite right.

If you get a quote from them I'd be very interested to know what they would take to do the procedure, just as a matter of interest.

Good luck!

 

[KS95]

I'll come back and update once I've rang them!

 

[John202020]

This is also a text book non Fiat dealer replacement issue, possibly the only item you should always have a genuine fiat do

 

[KS95]

This is also a text book non Fiat dealer replacement issue, possibly the only item you should always have a genuine fiat do

Damn, I'll try to remember that if I'm still driving it in four years time!

 

[steveras57]

Damn, I'll try to remember that if I'm still driving it in four years time!

dont mater if the timings out if theres no petrol left!.

 

[John202020]

Damn, I'll try to remember that if I'm still driving it in four years time!

It wasn't that expensive up here £430 Inc water pump which given dealer prices isn't bad?
I pushed the last belt to 7 years before replacing

 

[steveras57]

It wasn't that expensive up here £430 Inc water pump which given dealer prices isn't bad?
I pushed the last belt to 7 years before replacing

leave it ten years and you can push the whole car!

 

[Pugglt Auld Jock]

It wasn't that expensive up here £430 Inc water pump which given dealer prices isn't bad?
I pushed the last belt to 7 years before replacing

I was very suspicious of cam belts when they first started turning up in cars. They didn't seem to be as reliable as chains or, much more reliable, gears. We seemed to get a steady stream of cars which had suffered horrific failures requiring expensive repairs. Then people, mostly, got the message that you had to renew them every 4 or 5 years or around 50,000 miles - but there were those with even shorter recommendations. Over the years the design and materials seem to have improved enormously and it's not at all so common to hear of an actual belt failure. Now it's more likely to be the water pump or tensioner/idler bearings packing in resulting in the belt jumping the pulley - which is actually good because a failing belt rarely makes much noise whereas a bearing is usually pretty obvious.

A case in point is the EA211 series engines which you find in many VAG vehicles. I'd been looking at these for quite a while before I bought my Ibiza back in 2016. VAG were claiming that the belt was a lifetime fitment at that time with no recommended renewal interval, which then seemed to change to around 5 or 6 years or 70,000 miles (whichever came first). I got our local indy to renew it at 6 years with around 30,000 miles on her and the old belt looked literally brand new without even the smallest crack or defect. About 18 months ago I part exchanged her for the Skoda Scala I'm now running which has the same EA211 family 3 cylinder engine and the dealer tells me they've gone back to saying there's no recommended replacement interval, it's a lifetime fitment - which I believe they define as not less than 10 years at which time it should be given a visual inspection at major services. If I keep the car long enough I'll probably renew at around 7 to 8 years but I'll take the top cover off the belt cover and have a look at it once it's about 5 to 6 years old.

So, for me, I'd take a car with a belt all day long - but not a "wet belt" thank you very much. In fact I'd go so far as to say I wouldn't entertain a "wet cam belt" - which is one that runs in the engine oil - under any circumstances! Chain drives, now that everything is over head cam, use long chains - compared to the old over head valve engines with pushrods - so chain wear becomes a much bigger problem - and there have been a number of well respected manufacturer's who've had big chain wear problems over recent years with them wearing out sooner or in a similar mileage to a belt but repair/replacement costs are considerably higher. On the subject of "wet belts" I was "shocked" to discover recently that the small petrol engine in the Civic runs a wet belt and has the same problems with oil supplies to the engine itself and auxiliary components, like the turbo for instance, as the belt ages. I've messed about with a few smaller Hondas over the years and I've always thought they were exceptionally well engineered - even their cam chains seem to go on to achieve "starship" mileages - so I'm actually rather shocked to find they employed a wet belt on these engines.

Becky's belt is now 6 years old but she only does about 1500 miles a year. This very low mileage coupled to a lot of town driving, is not ideal for belt life but early last year, when I last looked at it, it was looking very good with no noticeable degradation. I'm going to check it again very soon and am hoping to get another year out of it as I decide exactly what I'm going to do about this rear axle.

 

[Mike1alike]

Do you think it sounds like a phonic wheel?

I do not think phonic wheel has anything to do with your problem and here's what our colleague thinks of it, you might be interested, posted in this other topic

Same with "phonic wheel reset/adaptation/whatever". It is one of the most useless features in the FES/MES programs.
It does almost nothing (cosmetic changes). It has nothing to do with the engine starting (or not). So forget about it for now.
Clueless people are fixated, obsessed with it (forums are full of "advice" like that: have you done The Reset, do the reset, you must do the reset, your car needs a phonic wheel procedure, learning, reset,...crazy). Engine won't start = phonic wheel reset. Rough idle = phonic wheel reset. Misfire = reset...

As for what's causing your problem, my money is on the faulty thermostat. The thermostat is broke, it doesn't close when it should. When you hit high speed, the wind hitting the radiator cools down the cooling liquid, that beeing a moment thermostat should close to keep the coolant within working temperature. But it doesn't and the coolant temperature overall drops too much. You won't find any related errors stored but you do get the intermittent check engine light because ECU feels something is not quite right.
So nevermind pausing the music but watch the temperature gauge. Normal needle position is bang on the middle, I say you'll see yours lower than that, possibly just a quarter on the clock.

 

[KS95]

Took the car out today and temp was slap bang in the middle when the light appeared

 

[Mike1alike]

Ok. That scenario was the first time I've seen the check engine light flickering, it was bad thermostat at the time. Obviously it's not the case at yours. At least it was easy for you to check and it didn't cost you anything.
Now, I remembered another scenario when the intermitent check light came on, I think you're not gonna like that, but if that's the case you'll have to do the checkings and proper repair in the end.
And this one had the "misfire error' on mine too, so chances are high. Worn valve seals was given me that. It was exactly like yours, when hitting ~70 mph the check light would come on intermittently. If I would have continued accelerating the light would continue flickering, if I would decelerate the light would go off in about 1 minute or so. And misfire errors would be stored on ECU.
I did the seal replacement because I knew I have to, the engine was "eating" a lot of oil at the time. So I took the CH down, cleaned it, the valves and the engine block, put new seals, new HG and so on. I didn't connect that error with this at the time, but looking back I think this was causing it. It didn't come back after that. And technically, oil did get burned inside the combustion chambers, traces were lots in there. So I'm thinking when you go high speed the oil pressure is higher, that made more oil get inside combustion chambers and affecting the combustion. As yours, at mine wasn't proper misfire, the engine felt running on all cylinders, but obviously it wasn't in the correct specs. I think misfire error is thrown by the knocking sensor data, so it read the combustion is lower.
So first thing, how is the oil level and oil consumption on the engine? And as far as you know, were the valve seals ever replaced on the engine?