Joined: Tue Sep 15, 2015 6:38 pm. x 5018. Re: ET6G gearbox fault. by GiveMeABreak » Fri Jul 24, 2020 3:52 pm. Hi Steen. Your Gearbox ECU has gone into a backup mode caused by the fault. P171A means there is coherence fault in the CAN and brake wiring and this will prevent gears above third being selected. Suspect areas: Gearbox ECU. This is precisely the theme of our article. First, we’ll briefly explain the different types of automatic gearboxes, then, in a second step, which problems you might face with the gearbox of your Citroen C4 Picasso 2 , and, finally, how to fix them. The different sort of automatic gearbox of a Citroen C4 Picasso 2 . The car juddered, beeped and died and would not restart, it was showing anti-pollution fault, gearbox fault & handbrake fault one after the other. The handbrake did operate manually. I got assistance to push it into the road works to allow the traffic to flow. I checked the warning logs and all of the above faults were listed. My 1.6 HDi Manual Gearbox has it. It works a treat. No need to apply any 'special' pressure to the pedal. I just hold the car on a slope with the footbrake, then release, and all the time it takes to move to the throttle and then find the biting point on the clutch, it holds the car. This can be resolved very quickly and easily by purchasing a repair kit. The old part number is 6450XZ, the new part number is 1607044080 from a Citroen or Peugeot dealer (they can both order it, my Citroen dealer had it in stock!). You will need the part number as my dealer hadn't heard of the fault (but had the part on the shelf?). I have a 2003 citroen xsara 2-0 hdi auto 5 door saloon it has an anoying gear box fault after starting the car from cold and runnig it for about ten minuts the sport & snow lights come on and the car … read more Add 0,5 additional litres of oil in the gearbox. Repeat the top-up procedure. N.B. : The level of oil is correct when the stream of oil becomes drop by drop. Refit the oil level plug ( 3) (equipped with a new seal) Tighten to 2,4 daN.m. 4.3. Check the oil level (continued) Refit the filler plug ( 2) (equipped with a new seal) Tighten to 2,4 daN.m. I have Lexia and Diagbox which indicates the car thinks the front N/S wheel is travelling at 255kph. They also advise a Short circuit to positive or short circuit to earth or open circuit. I suspect all the problems/warnings come from this fault. What I have done: 1. replaced brake switch (before lexia) 2. checked gearbox selector oil (before Citroen c4 Picasso with semi-automatic gearbox, when cold staring when you try to drive of it shunts like in the old days when you had to pull the chock out to get the car going. When its warm ( car r … read more F14 15 Air conditioning, Bluetooth® hands-free kit, automatic gearbox selector, airbag, instrument panel F15 30 Locking and unlocking F16 SHUNT F17 40 Heated rear screen Fuse box number 2 Citroen C4 Picasso - fuse box - under dashboard 2 Citroen C4 Picasso – fuse box – under dashboard (fuse box numer 2) Reference Ampere rating [A] Function AB1IT.