2003 1.4 8 valve, running rough

This is the first fault P1631

This is the second fault code P2101

Hi, I spent an hour on the car again yesterday, I started the car up first thing and revved it up as soon as it fired up and it sounded great running quite nice, turned the engine off, turned the key and stated it without revving, running rough again misfiring and possibly over fuelling. I change the temp sensor, and no change. does anyone think I have an air leak on the inlet?. I am going back to my original thoughts', when I turn the key with no throttle it is trying to get air, it is hard as the throttle body is closed, When I start the car and rev it up it is getting loads of air and the air leak is not so noticeable, of am I still barking up the wrong tree, My brother is convinced it is a ecu problem, but I am not so sure.


Happy easter

Paul

paullap wrote:This is the second fault code P2101

P2101 Fault

You have a fault to look into - as the description says - Motorised Throttle Coherence fault.

The throttle control electrical signal is not correct. The 2 signals should correlate, but if the ECU sees the 2 tracks that don't correlate (Coherence) it will give a fault. Check wiring and plugs for the circuit as a first thing to check. Also look at the accelerator pedal wiring and the 'converted to RHD' accelerator pedal connector on the passenger side.

Does lexia not mention something along the lines of:

For S2000PM1 as fitted to TU3 engine in Citroen C3, check for harness problems. It may be necessary to replace the multi connector on the motorised throttle unit and delete the connector under the glove box, where the manufacturer has adapted from left hand drive.

There is a topic here - P2101 Fix by 'Delete the connector' that helps with this.

paullap wrote:This is the first fault P1631

P1631 fault

What does lexia say about this, other than the screen shot?

Hi, For the fault P1631, I don't remember any suggestions from lexia , I will check the connector and I will let you know how I gat on, Thanks for taking the time to help me trying resolve this problem, So you don't think it is down to an air leak on the inlet manifold?.


Paul

paullap wrote:So you don't think it is down to an air leak on the inlet manifold?.

The 2 error codes you have posted do not point to an air leak on the manifold. That's not to say there isn't one.

It would be best to fix the reasons for the 2 fault codes so they will clear, then you can diagnose further (if necessary) as to any other issues you come across.

paullap wrote:For the fault P1631, I don't remember any suggestions from lexia

It would be worth checking again and pressing the button that prompts lexia to give you the answer for this one. I had a quick look and found 'ECU Defect', ' Engine control module (ECM) - processor fault' and 'Internal ECM fault / Configuration fault' for P1631, So I would be very interested to see what lexia says to do with that.

OK, Thanks for that I will have a go this evening, I will let you know how I get on.


Thanks again

Paul

paullap wrote:OK, Thanks for that I will have a go this evening, I will let you know how I get on.

Thanks, updates would be useful. My advice is to get to grips with lexia and use it to its full potential. Its the dealer tool, so it can do the things the dealer can do. Some faults in lexia have a comprehensive list of suggested checks and tests to do which can be a real help in diagnosing what is going on.

Hi, update, I have been going back to basics, I thought I would check the valve timing, spot on , now problems there, then I checked the connection under the fuse box for the accelerator pedal, cleaned them up and plugged in the lap top and lexia, cleared all the codes and took it for a hard drive, no codes now, drove fine, came back in to the drive tick over no problems, turn off then key, and then re start, runs rough like the engine is hunting for about 15 seconds then clears. I start the car without pressing the accelerator. I have now done this several times and the same thing, hunting for about 15 seconds then it clears.


Paul

Still trying to sort out this problem, my thoughts, When I start the car, cold or warm, it is hunting for about 30 seconds and then clears, and will drive fine, it is as if it is not getting the correct information to the ecu for that amount of time, now if the car is hunting, is this because it has a weak fuel mixture?. if so the ecu would recognise this and then pump more fuel back in. giving it the rich mixture, that is why the oxygen sensor is black with soot and the spark plugs also. or am I barking up the wrong tree again, I have no codes showing now, but it still idles rough to start with and suspect it is heavy on fuel consumption.


Paul