Technical Potential ECU Problems?

[SamNeedham123]

Hi,

Back in June, le Mother purchased a 2004 Fiat Punto Dynamic with a 1.3JTD MultiJet Diesel coupled to an Automatic Gearbox, it only had around 24,000 miles on it and was in pretty nice condition. However, we've since had typically Italian Electrical Issues pretty soon after purchasing.

It started with the Temperature Guage going up to maximum with it saying 'Max. Temperature' on the Trip Computer Screen when the engine was started. It then proceeded to go onto saying that there was a Sidelight failure (which isn't true as the bulb works perfectly fine). The car has been back to the garage multiple times during the warranty period in regards to these electrical gremlins to which they have responded that it hasn't been driven enough and the battery is going flat. So, they put it on Trickle Charge for a few days, and the problem goes away until a few days later.

However, on Friday, whilst the vehicle was driving at around 40mph, the car started acting up again. This time, the Electric Power Steering stopped functioning and came up with 'Steering Failure' - my Mum was lucky that she was just passing the garage at the time, to which they responded with their natural 'it hasn't been driven enough'.

Although my Mum is a pretty low mileage user and uses the car a few times a week to do shopping - that shouldn't be enough to cause these sorts of issues (I sometimes leave my Ibiza TDi sat for nearly a week - and even with a weak battery, doesn't have such issues). When we got the car back on Tuesday, the Punto was then taken to Halfords for their battery/alternator check which showed no issues, but we were advised to go to an Auto-Electrician to have the car more closely looked at, as the Power Steering failing during driving shouldn't really happen, and I would imagine only if the alternator failed would something so extreme occur.

We have spoken to an Auto-Electrician who is pretty confident that the ECU is on its way out due to water ingress (to which the garage the car was purchased from claims is rubbish), but it seems to be the only real answer to the problems we are having. I mean, it's got a pretty new Yuasa battery on it, so it should be able to sit for a while and not have problems!

If any of you guys could point us in the right direction of where the problem may lay, it'd be highly appreciated!

Thanks!

 

[Brendan W]

The power steering draws a huge current and is capable of dropping the system voltage quite a bit. Any deficiency in the battery will trip it out. This is especially true just after starting from cold when un-parking as high steering inputs are required. However your battery is new and the charging is ok. Which leaves, could you have a current leak and what size Ah is the battery.
Power steering failure whilst driving along can be due to relay failure in the motor. I thought this was sorted on post 03 cars with contactless relays. It can also be a failure of the torque sensors which is remanufactured column time. This is relatively rare. Check the condition of the main earth strap from the gearbox to the battery and also the smaller piggyback wire on the negative terminal.
There is a sticky at the top about p/s issues. It might be of some help. I cured mine with an new battery initially and six years later by replacing the relays in the motor.
Just noticed, your first post Hi and Welcome :wave:

 

[Scudmonkey]

The power steering draws a huge current and is capable of dropping the system voltage quite a bit. Any deficiency in the battery will trip it out. This is especially true just after starting from cold when un-parking as high steering inputs are required. However your battery is new and the charging is ok. Which leaves, could you have a current leak and what size Ah is the battery.
Power steering failure whilst driving along can be due to relay failure in the motor. I thought this was sorted on post 03 cars with contactless relays. It can also be a failure of the torque sensors which is remanufactured column time. This is relatively rare. Check the condition of the main earth strap from the gearbox to the battery and also the smaller piggyback wire on the negative terminal.
There is a sticky at the top about p/s issues. It might be of some help. I cured mine with an new battery initially and six years later by replacing the relays in the motor.
Just noticed, your first post Hi and Welcome :wave:

2004 is Mk2/B..no relays on the PAS motor

 

[s and b]

temp gauge going haywire can indeed be body computer going faulty
this is behind the panel to the right of the steering wheel and not to be confused with the ecu
a global scan by a good auto electrician should confirm

 

[judderbar]

Power steering failure with insufficient battery/alternator voltage is a known common problem for your car. The alternator voltage is regulated by a box on the alternator. These cars should produce almost exactly 14V no problem with the engine at idle or slightly above idle.