General Lambda problem?

Currently reading:
General Lambda problem?

michael baxter

New member
Oct 4, 2007
I have a problem with a 1996 Cinq Sporting where the engine switches to limp home mode once hot. This is what I know:

1. The engine starts and runs fine from cold
2. Once warm, it switches into limp home mode
3. When started from warm, it will run in limp home mode
4. After taking the lambda sensor off for inspection, I noticed it had a slight rattle - as if something was loose or broken.
5. When cold the engine runs without fault and shows no sign of any problem

Part of the problem is I am 50 miles away from the nearest Fiat dealership, and can't take it in to have the ECU read for error codes.

On the basis of the symptoms above, I would appreciate any suggestion of what is wrong.

Many thanks!
Last edited:
sounds like it could be a lambda sensor. seing as when the car is started cold the ECU runs in open mode which basically means that it isnt listening to the sensors be it lambda, knock sensor etc. this is to get the car to operating temperature easier and something to do with the fuel/air ratio. but when it warms up and registers that it has it changes and the ECU runs in closed mode which means that it starts listening to the various sensors and so it senses somethings wrong (i.e by the sounds of it your lambda) and decides to turn on the limp home mode. have you got an SPI or MPI seicento?
id say have a good hunt thourh your engine bay for anything else. becuase if you dont look for a problem youll never find one. and try a new lambda and see if it cures it. if it doesnt then at least we know that thats oka nd weve narrowed down the problem
whats limp home mode?

my lambda went a couple of months ago, it ran ok but idled high and used more fuel.

I bought a universal one off ebay, for less than £30, while removing old one I unplugged ecu, then plugged it back in when fitted, car ran fantastic ever since, smooth idle, amazing mpg, all round smoother drive.