Technical My Grande Punto electronics have gone crazy. I need advice.

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Technical My Grande Punto electronics have gone crazy. I need advice.


New member
Apr 7, 2024
cacaprout city
Hi folks.

Here we go... Fiat Grande Punto, 1.2 and 68 hp. Bought it in 2011. Good little car, never let me down. I can do 700 km with 70 euros of gasoline.

But I presently have a host of issues when driving it on highways. I know, city cars are not build for highways - but no choice.

For a start, the dashboard varied lights are screwed up. (not my car - ) Start-and-stop, door locks: the lights no longer work correctly.

But there is much worse. The engine electronic controls seemingly have gone bonkers. When I accelerate past 110 kph on the highway, at some point the electronic somewhat "panic" and try "saving" the engine by dropping power and slowing down the car to 80 kph. Which is quite dangerous ! I've noted the phenomena happens on highways with declivity and ramps: the car just don't want to climb, at least not faster than 90-100. Also when the engine reach 4000 rpm.

Recently I've noticed that the start-and-stop light actually lit at this very moment ! No kidding - WDF, I don't know !!!

The two issues seems to be related, which is hardly surprising. Maybe the start-and-stop has screwed the engine parameters, one way or another.

I've found the OBD-2 and hired my stepbrother who is a gifted mechanics. He also live near a highway. Next weekend we will hit the highway and try pinning down the problem - and eventually reinitialize the parameters.

Do you think that's a reasonable move ? My older Punto (1996 - 2011) had the exact same FIRE 1.2 engine and never did that. Clearly the 2000's electronic control of the engine have gone crazy. The Fiat mechanics tried the OBD-2 but found nothing, which is not that surprising: the problem only happens pushing the car hard and fast, climbing on a highway. Not easy to pin down.

Anybody ever had such issues with a (Grande) Punto ? From memory, I think engine parameters and issues have numbers. Looking on the Internet I had found mine might be (from memory) in the P0300 series (301 to 304, I'll check again).

Cheers !
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Sounds like lack of basic maintenance, neglected car, abused almost (you can debunk this by showing maintenance history).
Weird things in electronics are electrical power quality related most of the time.
Charging, battery, main "ground/earth". There is no "mystery" faults.
Check this out:
Random example (test question, how much you care): do you know about water drains flooding the alternators, or is this new info to you?

Power (mechanical) limit can be related to electronics (like sensors) or basic mechanics (like timing and valve clearance/lash, the most neglected thing in FIRE 8V family engines ever). Ask your stepbrother about this.
And P_300 series codes are ignition system related mostly (misfire can be caused by other systems like fuel too).

Most important tip: you don't just swap parts (let's throw new coils module). You Diagnose what's wrong. Real mechanics do it using oscilloscope.
Show this channels to your gifted brother (if he likes it and understands = he's OK, a real-deal, if not, he's no-good): name a few.
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Sounds like your clutch is slipping.

In the other thread it says the car has done 204,000km, so it doesn't have much monetary value. Its only worth getting repaired if your brother can do it. Otherwise its the scrapyard i'm afraid.