Technical Project Jean | Fiat 500 by Diesel - Misfires & Throttle Errors

[ReadyPlayerOne]

Hey

So for those of you who have read the Newbie Forumn, I’m on a ‘quest’ to restore my wife’s car to its former glory. There are things wrong due to her age (Car not wife, but that could be another post ) and I’m looking for help and guidance to resolve this. The list isn’t long, just ‘annoying’ as good old Jean hasn’t been looked after as she deserves. I want to help others and love what you all have here so if you would accept me I’m going to document ‘Project Jean’ so that it can help others in the future. I will have a read and a search for existing posts. If I find them I will link to them to keep them ‘fresh’.

Right….

So car is misfiring, not really noticeable unless you know it’s there.

Quick scan and I get the following:

P0120 (Throttle position (TP) switch - Circuit Malfunction
P0300 (Random/multiple cylinder(s) - misfire detected
P0301 (Cylinder 1 -misfire detected
P0304 (Cylinder 4 - misfire detected
P1220 (Series Throttle Control System Malfunction

I’ve replaced the coil pack, and ECU with no joy, this leads me back to it being something around a sensor/accelerator pedal.

Thoughts?

Picture of screenshot of errors for full reference.

 

[steveras57]

sounds like the throttle position sensor attached to the pedal might be playing up!

 

[Ralf S.]

Agree with Steveras57...

I dunno about the misfire errors on 1 & 4 though.. in older tech' the coils wouldn't care about the throttle sensor.. they'd fire regardless based on the cam position... but maybe the electronics are more synchronised these days.

Ralf S.