Stilo fault codes 1684 1687 1220

Did you have to put a new linear pressure switch on?

Can the accelerator potentiometer cause the problem? Or the comms between? Also have a cruise control fitted to the steering column connector - which has been working fine.

Did you have to put a new linear pressure switch on?
No I just cleared the code and started her up as the problem (me!) was now gone

Can the accelerator potentiometer cause the problem? Or the comms between?
Yes - makes it interesting doesn't it. With TPS fault codes then I suppose the first port of call is there and then work back as the accelerator pots aren't too easy to get to. Two pots in tandem there at the accelerator so it should make it more reliable so I think i'd check the output from the accelerator pots at the ecu and bear in mind they go through the D4 connector- the horror!

Cheers for that Deckchair5 - nice to get some answers - dealership are still scratching their heads!

take it to a good one then

Choice was limited on limp home mode!!

lol true !

Hi - dealership have been back in touch and are saying that a fiat tech has diagnosed the problem and that both throttle body and ecu need to be changed as a matched pair - is this true or are they pulling a fast one?
Many thanks

I have seen both components go down to be honest but I stand by most post (#6) as my first point of testing.

Ta for replying - I appreciate the problem is a new ECU - but does that mean it needs a new throttle body as well?
I'm just not sure it needs a new throttle body too - they've fitted the new one and have then diagnosed the ECU needs replacing - yet the new throttle body made no difference.

Well, never heard of a throttle body and an ECU ever needing to be "a matched pair". How is anyone going to change one of those items ever again if they always have to be replaced together. Compatible, yes, but a matched pair? Sounds like antiques roadshow. Maybe they mean that a new ECU needs a newer design throttle body

Are you paying for this or is this a warranty job? To replace a throttle body, it does nothing to repair the fault and then they say it needs replacing again with another one sounds novel and is ok as long as you're not paying for each one. What's the reasoning?

ECU needing replacement might well be needing to bite the bullet as you're between a rock and a hard place but check the car out thoroughly before paying any bills and driving it away

Hi Deckchair5 - they changed the throttle body, which made no difference, now are telling me they need to replace the ecu as well, so are saying both my throttle body and ecu were at fault. Car out of warranty as 02 plate so is at my cost. My feeling is that they're trying it on as wouldn't it make sense to try a recon ecu with my old throttle body? As it's a recon ecu they're going to fit is there any reason why it wouldn't be compatible with my old throttle body?

Well, if they wrongly diagnosed and replaced the throttle body and it does nothing to improve things then it would be logical and reasonable to ask for the old one to be put back. In reality, I think they may send the old one off on a sale and return as it's a reconditionable part so it may not be around any more. You'd have to check

I would think that all the 1.6 parts would be compatible and not need to be "matched". They do the "matching" with a throttle relearn procedure

Thanks for that - I've told dealership not to send either the old ecu or the old throttle body back until car is fixed and I give my say so. The old ecu won't perform (or complete) a throttle relearn, so surely that points to it being the ecu, or a component it tests during relearn - does it only test the throttle body, or does it test other components? As changing the throttle body made no difference, it points to the ECU. So does logic suggest trying the old throttle body with a recon ecu as a first try? Could the D4 connector be at fault, cruise control fault, or the accelerator potentiometer (does the relearn procedure check any of these?

Ta

Wow so many questions.
Well the throttle relearn is communications between the ECU and the throttle body and therefore also the communication lines in between. A bad connection or connector would cause just as much grief

Ref this drawing


The gas pedal comms go through the D4 connector to the ECU so imagine the D4 is between the gas pedal and the ECM as they call it here