Technical Probs with Fiat 500 2020 Error Codes

[helen1973]

Having issues recently with Fiat 500 MHEV 2020. Lots of error codes. Garage diagnosed loose connection and new aux Battery. Passed MOT and had minor service recently. Now error codes have re-appeared. Used an OBD2 Scanner and lots of issues. Help!

S

 

[Jockstrap]

Don't know which scanner you're using.

But looks like history status means not active.

Just delete the error codes. Could be that the Fiat software blocking deletion by your reader.

 

[portland_bill]

Unlikely that so many issues have occurred at once. This is more likely to be a single connection, disrupting communication all along a line.
The body computer, behind the OBD connector needs checking for secure connections. Also check for any dampness.
Under the windscreen, there's a chamber wher the wiper motor sits. That catches rainwater, which should drain out, through two rubber 'duckbills'. Those duckbills can block, especially with dead rotting leaves. The chamber fills with water, and overflows into the car, often onto the body computer.

Although the battery has been replaced, check the connections are secure. Also check the earth cable from battery to body and engine. At 5 years old, this should still be good, but they do corrode internally, making a high resistance, causing a multitude of electrical issues. Squeeze and flex the cable along its length. It should not feel crunchy.

 

[helen1973]

Hi, thanks for the info so far. Just a little history with issues. Intermittent error issues for last 6 months appearing on dash. Unable to start 2 weeks ago with lots of error lights on dash. Garage picked up car and replaced aux battery and fixed loose connection. All good. Friday had mot and minor service - all OK. Yesterday, started playing up again with errors. Today, it wouldn't start. Same errors on dash. When I did get it to eventually start, error appeared after a minute or so with clicking noise from where aux battery is located under passenger seat. Just sat in it to try again, and it started straight away and drove round the block. Plugged in car pal obd scanner and came up with OL Fault B2 and u0431 error. Any ideas? Thanks

 

[helen1973]

Unlikely that so many issues have occurred at once. This is more likely to be a single connection, disrupting communication all along a line.
The body computer, behind the OBD connector needs checking for secure connections. Also check for any dampness.
Under the windscreen, there's a chamber wher the wiper motor sits. That catches rainwater, which should drain out, through two rubber 'duckbills'. Those duckbills can block, especially with dead rotting leaves. The chamber fills with water, and overflows into the car, often onto the body computer.

Although the battery has been replaced, check the connections are secure. Also check the earth cable from battery to body and engine. At 5 years old, this should still be good, but they do corrode internally, making a high resistance, causing a multitude of electrical issues. Squeeze and flex the cable along its length. It should not feel crunchy.

Could you reply to my update, if you can help. Thanks

 

[portland_bill]

Sorry, I don't spend much time at the computer, and emails deliberately not to my mobile. Peaceful that way.

Don't know what fault B2 is, but u0431 is common with flat batteries.
I'm guessing that being a mild hybrid, the normal battery position under the bonnet is full of hybrid stuff, so the starter battery is under the seat.
With the older non-hybrid cars, 500 and Panda, the battery is under the bonnet. When the battery gets old and weak, or the earth cable corrodes, starting the car takes a lot of current, robbing the clock, so that each start resets the clock to zero. The fix is either a new battery, a new earth cable, or both.

With the battery under the seat, the earth cable has further to go, and may well have different connection locations.

The clicking under the seat could be a relay, trying to pass the big current to the starter. The description of 'found a loose connection' is a bit vague, but that, whatever it was is presumably fine now. However, things were disturbed when the battery was replaced, and the connection is intermittent. From the battery are two large cables. The red one, positive, carries the current to the starter, and everything else. They are usually copper cored, and last well. However, it needs checking, from the battery, all along its length, to the starter. It may be damaged, corroded, externally or internally, or may have a loose connection at the other end. This needs to be done carefully, as it is live, and must not be shorted out to the car metalwork.
The black one, is the earth, and is more likely to be aluminium cored. Passes current OK, but not as flexible, and shorter lived. Cheaper for the manufacturer. These corrode internally, as well as at the connections. It probably passes under the car, because the battery is under the seat, so could be susceptible to damage. Again, this needs checking carefully, from battery, all along, to its connections with the vehicle body, and the engine. This is the most likely problem, although disappointing at only five years. Decent garages would replace this with a copper one.

 

[MN500]

@portland_bill. The mild hybrid has two batteries. The standard 12v battery under the bonnet, same as the 'normal' car. So there's no extra long earth cable to it.

The other battery under the passenger seat and is charged via the alternator when free-wheeling, no accelerator, in gear and above certain engine speed. This battery then provides the energy back to the alternator, becoming a motor and turning the (more robust) belt so assisting acceleration and starting the engine (under stop/start conditions).

It could still be an issue with the earth cable - an issue certainly known on other 500's, ECU dampness, or a loose connection somewhere. It's interesting the OP mentioned a previously loose connection but not exactly what. It might just need everything resetting properly.

As suggested, and not yet confirmed by the OP actually done, with obvoius caution, I would also be checking security of all plugs and wires particularly around both batteries, together with any dampness near the ECU. Then using a jump lead as a temporary earth to see if that helps. I'd also be checking the boot wiring loom on a 5 year old car to ensure any issue there isn't causing these crazy errors being logged.

 

[portland_bill]

@portland_bill. The mild hybrid has two batteries. The standard 12v battery under the bonnet, same as the 'normal' car. So there's no extra long earth cable to it.

The other battery under the passenger seat and is charged via the alternator when free-wheeling, no accelerator, in gear and above certain engine speed. This battery then provides the energy back to the alternator, becoming a motor and turning the (more robust) belt so assisting acceleration and starting the engine (under stop/start conditions).

It could still be an issue with the earth cable - an issue certainly known on other 500's, ECU dampness, or a loose connection somewhere. It's interesting the OP mentioned a previously loose connection but not exactly what. It might just need everything resetting properly.

As suggested, and not yet confirmed by the OP actually done, with obvoius caution, I would also be checking security of all plugs and wires particularly around both batteries, together with any dampness near the ECU. Then using a jump lead as a temporary earth to see if that helps. I'd also be checking the boot wiring loom on a 5 year old car to ensure any issue there isn't causing these crazy errors being logged.

Thanks for the info.
I understood the mild hybrid to work on 48v, so expected quite a large battery compared to the one under the bonnet. And that would be expensive, and the OP didn't mention a huge expense. So is the battery under the seat additional to the hybrid battery?
Does the car have a normal starter, or only the alternator starter? Is the battery under the seat for additional power for starting, and the one under the bonnet doing its usual other stuff at 12v. If the main feed or earth cables at the underbonnet battery are poor, that might prevent the aux battery relay from operating, so we get the big clicks, and no start. Need to look under the bonnet perhaps, not under the seat.

 

[MN500]

@portland_bill

The hybrid battery under the passenger seat is only 12v lithium and smaller in physical size than the standard 12v lead acid under the bonnet (which powers all normal systems). It is quickly drained in normal driving, providing a torque contribution when accelerating, but does recharge quickly. I would still expect a replacement to be very expensive.

The car has a normal starter, but under stop start conditions, the alternator (Fiat call it BSG, belt starter generator), restarts the engine. That works very well in practice, it's a smoother, quieter and quicker start than any other S/S car I've driven. Less wear on the starter is a bonus.

Am I correct that you are/were an ADI (as I am)? If so, you won't be impressed that the system encourages coasting by indicating on screen to select neutral when free-wheeling at speeds of below 18mph and switching the engine off on the move if done.

 

[portland_bill]

@portland_bill

The hybrid battery under the passenger seat is only 12v lithium and smaller in physical size than the standard 12v lead acid under the bonnet (which powers all normal systems). It is quickly drained in normal driving, providing a torque contribution when accelerating, but does recharge quickly. I would still expect a replacement to be very expensive.

The car has a normal starter, but under stop start conditions, the alternator (Fiat call it BSG, belt starter generator), restarts the engine. That works very well in practice, it's a smoother, quieter and quicker start than any other S/S car I've driven. Less wear on the starter is a bonus.

Am I correct that you are/were an ADI (as I am)? If so, you won't be impressed that the system encourages coasting by indicating on screen to select neutral when free-wheeling at speeds of below 18mph and switching the engine off on the move if done.

Thanks for that. I'm surprised it is only 12v, but that at least should be a small weight penalty, so the gain in fuel economy is greater than that used to carry itself around.

I am still an ADI, but have not seen a learner since covid (horrid creatures), preferring to concentrate on fleet work, with company car and van drivers. Less stress, more fun, more variety. Earnings are less, and travel can be up to 90 minutes each way sometimes, but as I now have my pensions, I work two days a week for a bit of pocket money and to keep me sane.
I'd heard about the coasting recommendation, not just Fiat. I believe it is still an offence, yet is being recommended by manufacturers.
Other offences created by the cars:
Auto main beam. Waits for the oncoming vehicle to come into view before dipping, so deliberately dazzling them.
Headlamps remaining on after you exit the car, staying for a few minutes. An offence to park with headlamps on.
Bad habits:
Holding the footbrake instead of using the handbrake, mostly necessary to hold many autos these days. Brake lights stay on, reducing their life as well as dazzling drivers behind.
Hill hold assist. Encouraging drivers to do the shuffle instead of using the handbrake and finding the clutch bite point properly.

 

[varesecrazy]

Hi, thanks for the info so far. Just a little history with issues. Intermittent error issues for last 6 months appearing on dash. Unable to start 2 weeks ago with lots of error lights on dash. Garage picked up car and replaced aux battery and fixed loose connection. All good. Friday had mot and minor service - all OK. Yesterday, started playing up again with errors. Today, it wouldn't start. Same errors on dash. When I did get it to eventually start, error appeared after a minute or so with clicking noise from where aux battery is located under passenger seat. Just sat in it to try again, and it started straight away and drove round the block. Plugged in car pal obd scanner and came up with OL Fault B2 and u0431 error. Any ideas? Thanks

Hi,
I am interested to see what happens here

Nobody spelled this out in Plain English..
U errors are CANBUS

The network connecting so much of the cars Electronics, and obviously Mild Hybrid has more than a traditional 500 or Panda


My last 3 x FIAT have been electrically "Bullet proof"

But over the years I have seen some very odd things..

In my mind I was wondering if you had the work covered by a Warranty, so didn't concern yourself with "component costs"..

Historically.. Many errors are caused by a sensor being starved of power : through a poor battery.. Or a bad connection

What kind of Garage is doing this work?

Do you think they are Big Enough to access all the right information and help?


What has Your ownership been like..

Years of trouble free motoring

Or Niggles all the way through the 9 Months of having the keys..?


Tell us more