citroen c3 speed sensor

the best bet is to read the codes and note them, then clear the codes and drive till the fault recurs, then read them. That vehicle lists 4 different VSS codes (did you note the number?), first thing to check is whether the lead is on nice and tight with clean connections. most probable location is on the gearbox near where the drive shafts come out, but being a citroen it might even be on one front wheel.

highly irrelevant, but made me think of the job it was to replaced speedo cable, from the hub of the left front wheel of my old beetle.

Sorry, I don't have the code number otherwise I might have googled it first. I do have a dongle to read the codes onto my laptop but it's something I bought from ebay. I just tried it and it's listing p0299, p0400, and p0401 but from what I have read these are turbo and egr problems: look for another thread soon ;(

if you have vacuum actuators for turbo, egr etc. then have a hunt for vacuum leaks. 0299 turbo low boost, 0400 egr flow malfunction, 0401egr insufficient flow. turbo low boost may just be a split pipe :)

Thanks. These are recurring faults. I had them this time last year. they lasted a couple of months then suddenly cured themselves, but have now come back again. I did have the egr valve replaced but that hasn't changed anything. A second garage found a leak on the turbo charger (torn O-ring) but clearly that was only part of the problem. It was suggested that the egr pipe might be coked up and that I should use injector cleaner in the fuel and drive it on some long motorway journeys to clean it but that hasn't solved things either.

Do I need any special equipment to test the vacuums? Do I attach a vacuum gauge to the turbo and egr?

TIA

find where the vacuum is supplied from and measure that using the gauge (just that, nothing else connected at all) then reconnect the extra bits (you will need a t piece (and some hose) which car shops sell for washer circuits) the vacuum reading should be the same with everything connected, it should only vary momentarily when things operate and in your case will probably drop when the throttle is wide open. when I was trying to find a similar problem on my sister's diesel vectra I spent a couple of days messing about until I discovered that none of the trouble codes say:'low vacuum' (which would give you a start) in that case the fault was a small split in the body of the inlet swirl system actuator (low throttle thingy), so when that was turned on the vacuum dropped to very low and of course that bit didn't actually operate. as the vacuum was very low when everything was connected, it was then a case of disconnect and plug pipes till the fault was found. if your vacuum readings are nice and high then that is probably not your fault, but it might be worth putting a long hose on the gauge and going for a drive to see what happens.

Thanks for the informative reply. I know vacuum losses were suggested when I posted about this problem last year but then the faults disappeared before I got around to opening the bonnet.

Certainly loss of pressure was an issue, as found by the leak on the turbo charger.

I was thinking of buying a Focus as a replacement but I understand it's the same engine, so I may get the same problems ;(

I've seen washer tubing and tees etc in halfrauds. If I ask for a vacuum gauge will they have one, or so you recommend I go somewhere else recommend a particular gauge?

Thanks again.

you do not need an expensive gauge as the precise readings are not too important. I imagine any half decent mechanics tool supplier will sell one, most car shops have a clark catalogue with all that sort of stuff in it. Carb cleaner is basically paint thinners, but convenient as it is in a spray with a tube.

I know it's an old thread, but others might find the solution here: