EML coming on in damp/wet conditions

Hi all,

My first post here, although I've spent quite a bit of time lurking before registering so have already got some useful information on this problem, but have hit a bit of a wall with it.

I've had my C3 for about 3 1/2 years, and on and off for the first year or so had quite a few problems with the EML coming on and the "Antipollution System Faulty" message coming up on the display - especially in damp/wet weather. A garage I took it to said it was the crankshaft sensor and fitted another one. The problem seemed to die down a bit until a good while later, but it came back, and I went through the same process (new crankshaft sensor). When this didn't solve it and the garage was stumped, I went to an auto electrician who had a good look at it all (and told me crankshaft sensor problems were really rare on C3s), he thought the best bet was to put in a new coil pack & all new plugs (Citroen parts). This was last November & seemed to do the trick, but last week, after the car had sat in heavy drizzle for 2 or 3 days, the problem came back. I have managed to 'run it off' as I think that moisture is getting in to the engine/electrics (or just even a sensor) and enough running/idling of the car makes it evaporate and the EML disappear.

This has been such a long-running problem, but I'm still convinced it's down to water/moisture getting in. On this forum I've read up on the water jets design fault, and soon after getting the new coil pack etc. fitted I ran silicone sealant round the base of the jets, which looked like it made a pretty good seal. I've had another look at the seal and it seems intact. The hose/piping from the bottle to the jets seems OK, and that this happened after the car sitting in drizzly weather makes me think that water's most likely getting in from the outside (although it could maybe be condensation?), but I don't know what to do to stop it. The pattern most definitely is damp/wet weather - this never flares up in dry weather. By the way, the fault code my Bluetooth diagnostic tool always shows is PO337 (crankshaft sensor/low input).

I remember reading on this forum about sealing a couple of holes at the top of the injectors, as this may also help (I'd have no idea how to do this and would need a guide - and a real dummies one at that.) Beyond sealing round the bases of the water jets on the bonnets (which I may touch up the sealant on in any case), I have no ideas and would really appreciate some help/suggestions.

Sorry for the length of my first post, but I wanted to give as much info as possible. Thanks in advance for any help.

Dazza.

Dazza wrote:I have no ideas and would really appreciate some help/suggestions.

Dazza wrote:the fault code my Bluetooth diagnostic tool always shows is PO337 (crankshaft sensor/low input).

It would be worth checking the wiring to the crank sensor, including the condition of the plug and the wiring back to the engine ECU, you may have a chafed wire or contaminated connector plug on the sensor.


The sensors don't normally go bad, its the wiring/connectors that give trouble.

Many thanks for the reply. The wiring & plug seem to be basically OK, and I had an auto electrician check it. Definitely something I'll keep an eye on, though. It's such a frustrating problem - other than being convinced that it's related to damp conditions, I can't pinpoint it. That aside, the car runs well, so it'll be a real pity if I have to call it a day with the car because of this - especially having persevered with it for so long...

Dazza wrote:Many thanks for the reply. The wiring & plug seem to be basically OK, and I had an auto electrician check it. Definitely something I'll keep an eye on, though. It's such a frustrating problem - other than being convinced that it's related to damp conditions, I can't pinpoint it. That aside, the car runs well, so it'll be a real pity if I have to call it a day with the car because of this - especially having persevered with it for so long...

How about testing on a dry day with a spray bottle fully of water. Start soaking sections of the wiring and sensors until you find the fault appear?

A can of water displacer or a hair drier may also be useful to confirm the location by drying it of water to see the fault clear (or allowed to be cleared).

Thanks for the reply and suggestion - I'll try to do that before long. I'm now fairly sure water's not getting in through the bonnet (I tested the silicone seal around the base of the washer jets by operating them and also spraying water around them - nothing appeared underside the bonnet). So I think it's more like atmospheric damp that's the problem, and still think that condensation might be a factor - when the cold/wet car is started up and the engine heat kicks in. I might be OK over the summer, but as the autumnal spell last week proved, I'll no doubt get more trouble from this as autumn/winter gets here. Thanks again - the needle has to be somewhere in this haystack!