Randombloke

Important point - did they just clear the fault or did they give you the code stored? No point paying for a diagnostic unless you get the info. If there was no code stored, mine has done this twice in 40k miles. The cure is to turn the engine off, wait for 3-4 minutes until you hear the clunk from behind the instruments and the speedo kick negative mph, then wait for a few more seconds before starting. Lights gone. If the light is staying on after doing this, then there should be a code. Action that code. It would also be worth checking the battery voltage, and that all earths are good. I now run my C5 with a small plug in voltmeter, which gives numbers, necessary in a Mk1 I think. It might be worth reseating all the plugs to the main ECU, having checked they are all clean.

Sorry, I meant a multimeter - it's resistance we need to measure..... As I understand it the sensor has 4 wires going to it....... Two of the wires should have a fixed resistance between them that does not change as the pedal is moved. One wire should have a resistance to one of the two "fixed" ones that goes up or down as you move the pedal, starting from a value close to the value across the first two wires, then going down to very low or vice versa, and the other wire might be the throttle idle switch, so either open or closed (zero resistance or open circuit), depending on which of the fixed wires you are testing to. You are looking for values that suddenly change across the pot wiper, or a pot wiper that does not go fully from one to another. Definitely something to test out of the car or with the sensor disconnected form the electrics - the multimeter might fry the ECU..... Does the car have cruise control? You could eliminate this by trying to use the cruise control to drive it faster. I was going to give you some cable numbers but I've just realised my manual covers only DW10ATED, I'm guessing this is a DW10BTED.

OK, it would be worth putting a volt meter across the pot and measuring resistance while someone presses the accelerator.

I'd also check that the throttle cable is not loose and that the throttle pot is ok, could be swapped out to prove.

Unless something is seriously wrong it will go into limp home mode with no much power and no turbo, but otherwise driveable. Did you ask the previous owner about the service intervals and whether the FAP (particle filter) had been serviced in line with the schedule? What state is the battery in?

Up Wrotham Hill 3 or 4 times in third gear as Coastline says. Maybe do the run up Wrotham, then turn around at the M25 intersection or just run up the A20 a few times then turn round at the top. A steep hill will allow you to welly it properly without exceeding the speed limit. These guys know what they are talking about. If all else fails, take it to Pete Simpson at Mid Kent Vehicle Services. 01622 794499.

You'll need to replace the whole assembly. Citroen don't sell the constituent parts. The one on my car suffered a failure of the diaphragm, which the diagnostics flagged up. I gave the duff one to a guy in Ireland who had a broken ball joint on his. He was able to connect the good diaphragm on his with the intact arm and ball joint on mine. Somewhere between 60 and 90 notes to buy, IIRC.

The sensors need to be coded into the car, so if one of them is replaced, a dealer visit is needed. There are a load of these valves on C5s and they don't seem to all be falling off...... however sometimes they have been noted to stop working, or give erroneous readings, or the car reports they are no longer present. Last I knew, no, but that may have changed. For sure there is no "official" presence.

I would go with Coastline Taxis advice, and check if the accelerator cable needs slack taken out of it first. It is the cheapest thing to check and sort out, and could be done for nothing if you can do the spanner work. I have seen this issue with other 2.2 C5s, and it was the slack in the cable. I have a 2.2 C5, and the power doesn't run out in lower gears at about 4,000 rpm. 4,500 is easily done and you need to be approaching 5,000 before it starts to tail off. After that, as iannez says it could be expensive.......

Worn CV joint?

Battery condition or battery connections. See advice elsewhere from Citroen techs.........

Yes, because it's only when the car is raised that the pump needs to run, on lowering the car pressure is simply dumped by a valve. The headlights flicker because the pump has a very big switch on surge current, like all big motors. When raising the car the pump needs to place more fluid in the hydraulic system. IIRC this only happens if you car has H3+, not H3.

No, not plus VAT. I think they replaced the roller on the other side, and I've not got the bill to hand as it was a while ago. There may have been some other small issue as I tend to save those up for visits. If I find the bill I'll post details.....

Temperature sensors are also relatively cheap, so even if it's not the fault then you are not badly out of pocket. I've had the odd temp sensor problem, but more usually it's a thermostat. I would also try and measure the crank sensor if possible. Long shot, but related to misfiring.

I know of 3 2.2s which broke belts and ended up at my local indy over a 6 week period, all were between 90 and 100k. I had mine done at 84k. Belt and new tensioners and rollers is about 500 notes, fitted. Damage can be between 1.5 and 2k. It was a no brainer for me as I was not intending to sell the car in the short term and therefore the money was going to be spent, all that altered was when.

It depends on when your car was made. European legislation said that all petrol cars had to comply with EOBD II from 2001, but diesel from only 2004. There is a podule I was tempted to buy on eBay for £30, but despite being assured it would work with the 2.2 diesel it did not. Any podule you buy will only support the standard parts of EOBD II, and will not do all the manufacturer specific stuff so will not cover suspension or other extras that might be done via diagnostics. Maybe if you can post the exact model and date of manufacture, someone might be able to help you. I know you say HPi 2003, but is that when it was made? ORGA or RPN can tell you precisely. This is an example of the pod I am wittering on about.

From memory put key in ignition. Turn to accessories position. Press and hold button on the end of LHS stalk for 5 seconds or until you hear a ding sound. Auto lights on. Same to turn them off. If this does not work let me know and I will consult Manuel.

Use it! It makes a big difference on twisty roads.

They are probably covering themselves as some indicator bulbs are orange. I know the ones in the rear cluster are not, but with selling stuff nowadays you must assume that some customers are idiots. Rear lights are 5W IIRC, so they cant replace those and brake lights are usually twin filament, so not those either. Seeing as they are sold as reversing but titled as fogs, they should be good for those two positions anyway. Like you I'm keen to try them....

Spheres tired and need recharging or replacement? They can be tested and recharged by an indy, OEM will only replace. kfk or iannez posted a simple lean on test for them somewhere on this forum. Height sensors/correctors stuck meaning car is running slightly too high and hence overly hard suspension?

Turbo and Anti Pollution? I would start looking at EGR problems. Do a Search for EGR and make the C5 forum the only one you search. The more you say the more it sounds like an EGR problem, if DW10ATED has an EGR valve. Be worth getting the Haynes manual. It's been out for over a month. Good luck. PS. You are probably hearing a lot more noise because the engine cover has been removed. Even with an engine cover in place with the windows open the turbo can be clearly heard. HTH.

It's a 110bhp so I'm guessing 8 valve or ATED engine. On the big cover on the engine it says HDi not HDi 16V, yes? So you can disregard the swirl control BS I posted. Sorry. Switch cleaner/contact lubricant from Maplin. HTH.

Clutch switch might need a dose of switch lubricant/contact cleaner if the fault returns.

I'm assuming that the "Anti Pollution" warning is what you're seeing in the screen when you scroll round to check diagnostic messages. So, the service light is coming on because it's triggered by the Anti Pollution. Have you checked the battery voltage? Have you considered doing a battery disconnecting type reset? Details are elsewhere on this forum....... Are there any wires exiting from the front (cat type box) section of the exhaust? If so, are they connected properly at both ends? Is it 16 valve, in which case does it have a swirl control valve and is that still working? Check for the actuating arm (thin rod with tiny plastic ball joint) still connected, and it could be the diaphragm is perforated?

Unlikely, you will need to check that the clutch pedal activates the switch, and that the switch itself is working.