Xsara 2000 strange issue

[some1else]

Hi!

I have a 2000 Xsara 1.6i automatic and I've been having some strange issues with it. It started with speedometer occasionally dropping to zero, accompanied by odometer stopping counting and gearbox starting to shift abruptly, or during shift be totally ignorant of gas pedal and have no output power for 2-3s before finally shifting. On this forum I saw another thread for a Peugeot 206 with almost identical problem, and the cause for it was a faulty ignition coil causing electrical interference. So I also changed the coil. It's definitely different than it was, but not good yet. After changing coils, the car now starts with speedo being on zero and with shifting issues, but after speedo starts working again (couple min or km), then everything works perfectly for the rest of the trip. Perhaps I need to do a longer drive to be totally sure of this claim though. I did two test drives of 10-15min with car being off for about 20min between the tests.
Did anyone here ever come across this issue or a similar one? Some pointers would be great!
It's also worth mentioning, that OBS readers do not communicate well with this car. I bought a Lexia 3 clone, but couldn't get that to work either. Firmware downgrade was impossible. I ended up returning that and will be buying another one with full chip, which I assume was the issue here.

[mickthemaverick]

Before you do anything else I'd suggest you carry out a BSi reset according to the procedure in the link below. That means that you will be starting from 0 with various sensors and may allow it to learn the new coil characteristics correctly. Then when you do get a decent diagnostic machine, clear the existing codes first and then run the engine and rescan for the current codes. viewtopic.php?p=601679#p601679

[xantia_v6]

It is likely that a year 2000 car has a speed sensor in the transmission and maybe that is faulty.. it would be at the back of the transmission, probably accessed from below.

[some1else]

Thanks for the BSI reset! I did that and took the car for a short ride. Speedo dropped to zero after about 1km. I drove back right away and transmission didn't have an issue during this, but it most likely would have, if I drove it for a little more. Speedo usually starts working shortly after the transmission has had its "cough cough" moment. So apparently the coil change did absolutely nothing

Edit: A friend did a scan with his tool, but it wasn't very helpful. A handheld cheap reader says there's 0 codes in memory.

[some1else]

I already did a transmission fluid change (AL4), considering changing solenoids next. As for the speed sensor, it's in the ABS and I assume there would be a dash light if there was a fault?