This is a common problem with 2016 Citroen C4 Grand Picasso. Apparently Citroen fitted rear torsion bars which were sub standard and therefore were originally replaced free of charge as they came to light. They have more recently been treating the problem with a foam injection to stop the movement which is causing the noises. The air suspension system in a Citroen C4 Grand Picasso works by using a compressor to pump air into the air springs, creating a cushion of air that supports the vehicle's weight. This system allows the car to adjust to varying load requirements and achieve a smooth, comfortable ride. The system is controlled by an ECU (Electronic Control Unit My wife’s Citroen C4 Grand Picasso (horrible thing) has a few electrical gremlins. Messages on the display: “Electrical Fault” (what exactly?) “The hand brake is faulty” (it wouldn’t surprise me, but it seems to be working normally). The key fobs don’t work. There’s a high pitched squealing noise, like a dog whistle, drives you mad. Hello, new to the site (and world of elderly Citroen ownership) This might be a bit of a story but bear with me, if you don't care for the back story, jump to below the line. I bought a C4 Grand Picasso from 2008 with ~300.000km on it, not a new racer, but need 7 seats for my family and since money doesn't grow on trees this was our option. Went to work this morning (30 mins drive) no problem, just now went to grab a lunch, 3 minutes into the drive Check Engine comes on stating "Antipollution Fault" C4 2005 Petrol 1.4. Had it someone else stall it several times while giving them a spin in an empty car park about 5 days ago (1st gear 1-3mph). Thu Jul 19 2018, 01:11pm. Member No: #51650. Joined: Jul 16 2018. Location: Darlington. Hi ive got a rear pneumatic suspension problem, I’ve changed both the air bags and so now it doesn’t sink but 3 months down the line “suspension faulty” and the pump won’t kick in at all. Lexia says fault code c1629 air compressor relay open circuit. It will go down withn 30 minst of switching the engine off if there's any weight in the car (passengers or if the caravan is hitched up). I think that there is a 3rd height sensor on the nearside. I've got Lexia/Diagbox 7.82 and it came up with a low voltage problem with a sensor so I may have found the problem. There is definately a Citroen Inforapid bulletin on the fuel flap problem on C4 Picassos. As far as I recall the problem is with the pin that releases the flap not moving back and forwards as normal. I'm sure the fix for dealers was to make a slight adjustment to this pin (rather than needing any new parts). I'll check out what it says and this C4 Picasso had no hot air inside the Cabin.All the flaps were working and a new pollen filter had been fitted.the pipes going to rad were both getting h 5816 posts · Joined 2020. #2 · Sep 11, 2022. I'm not sure, but a quick search suggests it is a Malfunction of the BGPA battery charge module. If the battery is working, then the module must be replaced with a new one. And the module is on positive battery terminal, again not sure of this. I'll PM you with something. W. QrQh.