Technical FIAT 500 potentiometer

[aarontennant]

I have a Fiat 500 sport 1.2 2008.

All in all its a nice car but plagued with faults I feel are just down to poor quality/cheap parts.

I have had all the "Known" issues so far. Top mounts needed replacing at less the 45,000 miles. Also changed track control arms at the same time.

Drivers door handle snapped, Which I fixed with the guide on this forum.

Now I have a engine warning light on the dashboard. Lucky I brough Fiat Ecu Scan a few years back for my old Fiat Punto Which was plagued with airbag warning lights, which just needed clearing. Anyway back to the 500, I have scanned the fiat which brought up the fault code P1220, Accelerator Potentiometer fault.

Im assuming this is a fault with the accelerator pedal as it's all built into one box. I was going to order the part from fiat at £83 and fit it myself, however I don't have the time at the moment and need a car ASAP.

This bring me onto the next point about Fiat dealers being very un-iterested and unhelpful. Tried to book it into fiat, earliest they could do was over a week away. Tried 3 dealers in surrey; Shepparton, epsom and Guildford (Guilford never called me back)

So I booked into fiat next week, but they wouldn't give me a courtesy car whilst it was in, I even offered to pay towards it... not interested. I booked it anyway didn't have much choice. Then googled around and found a Couple of Fiat specialist (not main dealer approved) and managed to get in in on Thursday with a courtesy car. If a non main dealer can offer me a free courtesy car why can't fiat.. the mind boggles. anyway I have booked it into Deens at Hampton Court, as a few people with alfa's have given good feedback, the technicians being fiat trained helped my decision.

My questions are

- Has anyone else had issues with the potentiometer/throttle?

- Has anyone had these issues with these or other main dealers?

- Has anyone used Deens of Hampton for fiat repairs or know of any good ones I may have missed ?

I will hopefully update this with the outcome incase anyone else has this issue.

 

[zanes]

This bring me onto the next point about Fiat dealers being very un-iterested and unhelpful. Tried to book it into fiat, earliest they could do was over a week away. Tried 3 dealers in surrey; Shepparton, epsom and Guildford (Guilford never called me back)

- Has anyone had these issues with these or other main dealers?

They all do that, Sir.

 

[aarontennant]

Is that all Fiat dealers or Dealers In general. I had good levels of service from BMW for my Mini Cooper S and the parts department were helpful although expensive.

 

[PuntoHowTo]

as customer service goes fiat have adopted the approach of 'if you can't be the best, be the best and being bad' so if you're used to BMW/mini customer service its no wonder you've been left sorely disappointed.

There seems to be a growing reputation for bad service from fiat recently throughout the dealer network, and fiat HQ seem as uninterested in solving the problems as the dealerships you dealt with were at helping you out.

 

[ahmett]

I have a Fiat 500 sport 1.2 2008.



All in all its a nice car but plagued with faults I feel are just down to poor quality/cheap parts.



I have had all the "Known" issues so far. Top mounts needed replacing at less the 45,000 miles. Also changed track control arms at the same time.



Drivers door handle snapped, Which I fixed with the guide on this forum.



Now I have a engine warning light on the dashboard. Lucky I brough Fiat Ecu Scan a few years back for my old Fiat Punto Which was plagued with airbag warning lights, which just needed clearing. Anyway back to the 500, I have scanned the fiat which brought up the fault code P1220, Accelerator Potentiometer fault.



Im assuming this is a fault with the accelerator pedal as it's all built into one box. I was going to order the part from fiat at £83 and fit it myself, however I don't have the time at the moment and need a car ASAP.



This bring me onto the next point about Fiat dealers being very un-iterested and unhelpful. Tried to book it into fiat, earliest they could do was over a week away. Tried 3 dealers in surrey; Shepparton, epsom and Guildford (Guilford never called me back)



So I booked into fiat next week, but they wouldn't give me a courtesy car whilst it was in, I even offered to pay towards it... not interested. I booked it anyway didn't have much choice. Then googled around and found a Couple of Fiat specialist (not main dealer approved) and managed to get in in on Thursday with a courtesy car. If a non main dealer can offer me a free courtesy car why can't fiat.. the mind boggles. anyway I have booked it into Deens at Hampton Court, as a few people with alfa's have given good feedback, the technicians being fiat trained helped my decision.



My questions are



- Has anyone else had issues with the potentiometer/throttle?



- Has anyone had these issues with these or other main dealers?



- Has anyone used Deens of Hampton for fiat repairs or know of any good ones I may have missed ?



I will hopefully update this with the outcome incase anyone else has this issue.

Use Bosch car service! They have the diagnostics tools and are quicker to help. That doesn't seem like a very big problem that would take long to fix, assuming the parts are readily available my favourite trick is driving in to the garage and saying I just started having this problem, please help me! They usually do, especially small garages who need your business ; forget fiat main dealers !

 

[aarontennant]

I have booked it into a not main dealer as they could do it much quicker. Thats one point I had is that the parts are hard to get from the dealers. I couldn't get top mounts from Fiat as they were on Back order! I ended up using 1 genuine one and an aftermarket one made by Borg and Beck, which was identical and a 3rd of the price. I even tried ordering them from Italy!

I don't mind paying for genuine parts but when you can't get them, you don't have choice but to buy oem spec aftermarket ones.

Sadly I have sold the Mini copper as the fiat was more economical and we didn't need two cars. Now I remember why it's good to have Two cars to fix the broken one!!

 

[jrkitching]

I don't mind paying for genuine parts

If it's failed prematurely, why would you want to buy another genuine part?

A decent aftermarket part from a reputable supplier will likely be better than the OEM part that failed.

 

[ahmett]

If it's failed prematurely, why would you want to buy another genuine part?

A decent aftermarket part from a reputable supplier will likely be better than the OEM part that failed.

my policy is very simple; NEVER use Fiat OEM parts unless there is no alternative = ) (as in my dualogic complete unit!)

 

[UFI]

There are two potentiometers inside a DBW pedal. My Renault developed a fault in the DBW system shortly after taking delivery. I've been driving on one POT for six months or so and won't be going to the dealer before the first service is due. In my car the fault hasn't illuminated the CEL or any other warnings.

 

[zanes]

There are two potentiometers inside a DBW pedal. My Renault developed a fault in the DBW system shortly after taking delivery. I've been driving on one POT for six months or so and won't be going to the dealer before the first service is due. In my car the fault hasn't illuminated the CEL or any other warnings.

Let's hope that one pot doesn't develop a fault- there are two in there for [very] good reason.

Is that all Fiat dealers or Dealers In general. I had good levels of service from BMW for my Mini Cooper S and the parts department were helpful although expensive.

Varies, but FIAT seem worse than most for attracting certain types of dealers. We've also had shonky service from VW, Mitsubishi and Skoda (all seemingly related to the fact we were looking at their small cars) but the two FIAT dealers I used were generally OK.

 

[aarontennant]

Let's hope that one pot doesn't develop a fault- there are two in there for [very] good reason.

Ahh that would explain why it still seems to be driving fine, although I have to use a touch more acceleration when pulling away at junctions. I only drove it to the garage, as it seemed a bit dangerous to drive a car with a DBW fault.

Wouldn't risk driving for a long period of time as had it failed earlier I would have been stranded on the M25 of all places, luckily it only came on as I got home. but if the second potentiometer failed, it could be quite dangerous.

 

[ahmett]

Ahh that would explain why it still seems to be driving fine, although I have to use a touch more acceleration when pulling away at junctions. I only drove it to the garage, as it seemed a bit dangerous to drive a car with a DBW fault.

Wouldn't risk driving for a long period of time as had it failed earlier I would have been stranded on the M25 of all places, luckily it only came on as I got home. but if the second potentiometer failed, it could be quite dangerous.

stranded on the m25? that would have definately put you on the Fiat hall of fame! would do wonders for the reputation of the Fiat 500 as the worst place to brake down in the UK = )

 

[zanes]

Ahh that would explain why it still seems to be driving fine, although I have to use a touch more acceleration when pulling away at junctions. I only drove it to the garage, as it seemed a bit dangerous to drive a car with a DBW fault.

Wouldn't risk driving for a long period of time as had it failed earlier I would have been stranded on the M25 of all places, luckily it only came on as I got home. but if the second potentiometer failed, it could be quite dangerous.

Correct. Essentially the two potentiometers are there to act as failsafes and referees for each other.

It seems from a quick look online that the two pots are designed to give a fixed offset between each other (so one could swing from 1 to 3V and the other from 2 to 4V, for example). In addition the control system looks for shorts or opens in each pot circuit.

With only one pot any short or open in that circuit would result in a loss of power. If that one pot was to fail at a sensible position (which is unlikely, but feasibly possible), without that second pot to act as a "referee", you could possibly end up with an engine stuck at full throttle.

I wouldn't risk it for any great length of time.

 

[UFI]

Let's hope that one pot doesn't develop a fault- there are two in there for [very] good reason.

Well, apparently on a Fiat it's a serious fault and the car throws a CEL, while Renault consider it a minor problem so it only logs as a pending code. Any normal motorist (the kind who doesn't always have a scan tool plugged in) would never know anything is amiss until it goes to the dealer.

POTs don't normally fail in a fixed position, they most often get 'noisy', which will cause the ECU to ignore it's input.