Limp mode definitive solution?

[Cliomaxx69]

Hi all, I sold my 172 a few years ago because life got in the way and I couldn't get that limp mode problem sorted. Changed many parts tried many of the solutions I found in this forum but never solved it and sold it that way.

Now that I have more time and money and I have a chance to buy that same car back, supposedly doesn't go into limp mode anymore after a throttle body change which I highly doubt, what is the definitive solution to ending this random limp mode for good?

Is it just a matter of redoing all the ecu and throttle body to pedal wire loom?

Cheers

 

[Cliomaxx69]

I figured after all these years there has to be a definitive solution for this awful problem

 

[hopgop1]

I went through the intermittent limp mode problem on my 182 and it's not come back. Assuming it's the standard throttle track circuit 1/2 inconsistency code.
My understanding is that it can be the throttle pedal, the throttle body, the wiring inbetween, or the ECU.
I'm lucky enough to live relatively close to Mick at Diamond motors, who's a well regarding specialist and a wiring guru, so I took it to him in the first instance, he tested the wiring and diagnosed the throttle body as at fault. Personally I wouldn't trust any used throttle body that may have the same intermittent fault (plus even the youngest will be 20+ years old now), so I bought a brand new genuine throttle body (technically a 197/200 part number as that's still available, but they're identical parts), which did cure the limp mode for a few months.
I then had the issue re-occur, so I bought a verified low mileage throttle pedal (no longer available new, although you may be able to get a standard mk2 e-pedal and swap the metal plate over), which didn't help.
I then figured the last thing to rule out was the ECU after reading an old thread where it was someone else's issue, after they had their battery short against the ECU cover. My car had a battery that was too large when I bought it and a broken positive terminal cover, so I thought that was a possibility, so I bought a 2nd hand ECU, sent it to EFI parts to be virginised (so I didn't have to swap the key barrel and UCH), swapped my old ECU for the 2nd hand viriginised one and I've not had limp mode once since and my 182 is my only car so it does get used.

Hope that wall of text helps, but if you buy the same car back you're taking a gamble that it's one of the easy fixes, if it's ultimately a wiring fault and you've not got good knowledge or a specialist to rely on, it may prove very difficult to solve. When I was talking to Mick it apparently only takes a small amount of damage to a wire to not throw any continuity faults, but to change the resistance enough to cause issues with the throttle readings.

 

[Cliomaxx69]

Thanks a lot for the reply, I remember you helped a lot when I was struggling with limp mode back then.

Just thinking about all this headache again, as much as I adore this car and would love to own it back I don't think I can handle all this lol. There aren't really any automotive electrical specialists here in France.

I bought a Forfour Brabus as a remplacement and it's objectively a better car in every single way, super reliable and fun, just lacks a bit of soul compared to these little Clios

Probably just a bit of nostalgia, I think I'm better off with my Forfour.

Glad yours is free of this hell and thanks again for all the help!

Might buy a 182 in a few years when I can afford to have 2 cars

 

[hopgop1]

Thanks a lot for the reply, I remember you helped a lot when I was struggling with limp mode back then.

Just thinking about all this headache again, as much as I adore this car and would love to own it back I don't think I can handle all this lol. There aren't really any automotive electrical specialists here in France.

I bought a Forfour Brabus as a remplacement and it's objectively a better car in every single way, super reliable and fun, just lacks a bit of soul compared to these little Clios

Probably just a bit of nostalgia, I think I'm better off with my Forfour.

Glad yours is free of this hell and thanks again for all the help!

Might buy a 182 in a few years when I can afford to have 2 cars

For sure, I think you'd be better off in a proven working one and save yourself the headache, even if you've got fond memories of your old one.
Will definitely keep my 182 when I ineviatably get into something different as a daily.

 

[Martin_172]

The donor car that I used to build my 182 van had a limp mode issue, the previous owner had thrown the parts cannon at it via a garage who were guessing.

It had a new accelerator pedal and a new throttle body, I unplugged the white connector under the fuse box, cleaned up the connections and it's been fine for years now.