Car is question is one of our fleet of french cars , a 2003 Xsara Picasso 2.0 petrol automatic.
We've ownded this car on and off for around 7/8 years ( we let our neighbours use it for 5 years on loan ).
After getting it back and fixing lots of little stuff it flew through an MOT about 3 weeks ago after bot being used for about 3 months.
The problem I'm struggling with is the auto shift into first when you go to pull off . After it gets warm of 15 mile sdriving when you pull up with your foot on the brake it drops out of drive and then slams in with a bang as you start to try to move off.
I know that the DPO box has an idle /drive set up operated by a connection from brake light switch to ECU . When you pull up stationary with foot on brake it takes the autobox out of gear and as soon as you release the pedal it goes back into gear...except it doesn't
I dropped it to my local auto guy and teh shift pressues were low indicative of warped valve body, apparently a common problem and the source of 99% of gearbox issues .
He removed the valve body , refaced and reassembled alonng with an oil change. Sadly this didn't resolve it .
I next changed the brake light switch in case it was faulty but again no joy.
The next thing was I remembered on his code reader it throwing up an erratic TPS reading.
Clasping this info I chnages the TPS ( standalone cable driven to stepper motor on inlet ) and..no change.
My question is does this have to re calibrated to read the new TPS and if so how ?
I'm £700 out of pocket with the same problem still and can't afford to throw anymore cash at it. I really don't want to scrap it as it's still a great drive and very usable .
Has anyone encuntered this problem before and how was it resolved please ? I'm convince dthat it is an electrical problem as the rest of the time the gearbox shifts beautifully and I've undertaken a 120 mile round trip with no issues APART from thsi one when into town driving?