Cruise & Speed Limiter Fault C5 X7

[vborovic]

Add to that list Brake Pads low

That's "inconsistent brake sensor data" ...

[uglybanana]

Ok I just tried the reset to the absolute letter given earlier and everything went ok, had to reset the clock but it didn't fix the cruise. I've just now had a closer look at the service docs and it says the procedure to remove and refit the battery is

Perform the following operations :
Switch off the ignition
Wait 3 minutes before disconnecting the battery
Disconnect the battery

But under the precautions to be taken section there are some extra steps and some specific differences the main ones being

For automatic gearboxes it needs to be in N not P before disconnecting the battery.
It says to put the window down.
To disconnect anything from the diagnostic socket.
It does also say though door can be left open if need be as long as enough time has passed for everything to shut down.
It says to wait 4 minutes not 3 minutes before disconnecting the battery and if you have an AL4 auto box you must wait at least 12 minutes and to wait 2 minutes not 1 minute after reconnecting the battery for an auto box before turning on the ignition.
Nothing about sidelights or keyfob for 10 seconds,nothing about not opening the door after reconnecting the battery and waiting.

Either I'm not reading this right or the the standard procedure written above which I've seen across many different sites and has probably been doing the rounds for years is not specific enough and/or out of date.

So to follow it by the service instructions it should be

Put the driver's window down, lift the bonnet and ensure all equipment is switched off.
If you have an auto gearbox put it in N.
Disconnect anything from the diagnostic socket.
Ensure all doors are closed and remove key from the ignition.
Wait for 4 minutes, (12 minutes or more if you have an AL4 auto gearbox) disconnect the vehicle battery and wait at least 1 minute.
Reconnect the vehicle battery, wait a further 1 minute (2 minutes if you have an auto gearbox)
Switch on the ignition and check for errors or faults. Do not start the engine.
Start the engine. Check the one touch function of windows, blinds, sunroof.
Switch off the engine, remove the key and check central locking.

Whether or not it makes an actual difference in triggering a reset I don't think so. I think most of the steps are to prevent problems but important if accuracy is supposed to be the name of the game with this. That being said the core steps are to turn things off, wait long enough for everything to shut down, disconnect the battery, wait, reconnect and test which is the same as on pretty much every car.

Look like it's going to be a lexia job to try and narrow it down. I've already got the software installed so just need to order the kit. Thanks for the help and I'll post back if I get it working. Nothing worse that searching for a problem you have finding someone with the same thing but no solution given.

[GiveMeABreak]

Ok. good luck with your Lexia - let us know what, if anything comes back when you get it installed.

[Stickyfinger]

where are you based ?

[vborovic]

I can never be amazed enough with instant-owners, who immediately know the car and how it works better then other owners (and I'm talking about advanced owners / repairmen / car-electricians, not your everyday the-car-drives-me-to-work-hence-it-works folks) who've had it for several years more ...

@uglybanana - Good for you that you'll get your Lexia kit, but if you don't want to take our advice and help, I don't know why have you registered here, since you know the required procedures better than the rest of us (including PSA trained/qualified staff that are at least more knowledgeable than most of us here put together)? In all fairness, the X7 is a pretty "new" car, and it has yet to show it's age related problems (when electrical bits start acting up more that what we currently know), so it is hard to get an exact answer to your issue (or to expect to find the actual solution ... I've only every seen it once, possibly posted on YouTube as a problem video, which never got solved).

[uglybanana]

I can never be amazed enough with instant-owners, who immediately know the car and how it works better then other owners (and I'm talking about advanced owners / repairmen / car-electricians, not your everyday the-car-drives-me-to-work-hence-it-works folks) who've had it for several years more ...

@uglybanana - Good for you that you'll get your Lexia kit, but if you don't want to take our advice and help, I don't know why have you registered here, since you know the required procedures better than the rest of us (including PSA trained/qualified staff that are at least more knowledgeable than most of us here put together)? In all fairness, the X7 is a pretty "new" car, and it has yet to show it's age related problems (when electrical bits start acting up more that what we currently know), so it is hard to get an exact answer to your issue (or to expect to find the actual solution ... I've only every seen it once, possibly posted on YouTube as a problem video, which never got solved).

Not really sure where that came from or why. I have been given one piece of advice in this thread which I actually did try. If you read everything I have written you would also see I have tried plenty of things first before posting and used logic to narrow it down. Then in an attempt to contribute rather than just take I read more into the service docs and highlighted the discrepancies between what the service docs say and what the standard procedure doing the rounds across the forums are. As not everyone may have these documents I thought it may help. I guess not. Seeing as I have just registered and only just bought a Citroen I'm not worthy of offering any advice and I now know my place.

Given that I have been told several times that accuracy is the key with the reset, if the service docs are to be taken as correct then those reset steps are out of date and they should not be posted anymore, nor at random to people who may have autos but I did also say I may be reading it wrong leaving it open for correction. Anyone with the docs can check and correct it or I can screenshot it and post for everyone to see.

Would you not agree that talking about accuracy and precision and then posting possibly inaccurate steps is more than a little bit ironic and counter productive. As you say there is not a lot of information around about the X7's which is all the more reason to try and be accurate and informative. After all isn't that the point of forums like these.

[Hell Razor5543]

It is known that (certainly for the earlier C series Citroens) they can be very sensitive electrically (as they have a lot of electronics), and just disconnecting the battery can cause unforeseen, illogical issues. Think of it as shutting down a PC. Do you pull the power lead out (or switch it off at the mains), or do you tell the O/S to shut down? The advantage about the battery disconnect routine is that it can (and has) cleared down glitches that had occurred (not problems, as such, but glitches), making the car be a nicer place to be. Problems (such as a failed device) would still be there, and would need the aid of a Lexia clone to diagnose.

The reason the battery disconnect routine is so complicated (and time consuming) is that there are numerous ECUs in a Citroen, and they all need to shut down cleanly and then be completely powered down, otherwise they are still in standby, with any glitches still dormant within them. If you look through the BSi reset routine I believe you will find members who have followed the instructions, and regained full and reliable usage of the car.

I cannot speak for the X7 C5s, but it may be that either they have a cleaner shut down routine (which helps to automatically clear any glitches), or you may well have been lucky.

[vborovic]

and used logic to narrow it down

Most of us had to find out the hard way that logic and PSA cars don't mix well ... our attempts in this topic were to steer you in the right direction (or at least to the right tool), which is widely recognized as the only (but not bomb-proof) method to actually do something to and with the car in terms of servicing it (but first eliminating the off-chance that the ECUs in your car have a temporary error which might be fixed by successful rebooting - something that you might (still) not have done successfully in your attempt(s))

[uglybanana]

I'm not saying the reset doesn't need to be done with care waiting for everything to shut down as that's the case with any modern car, I'm saying the commonly known BSI reset procedure copied and pasted from forum to forum for years now and also given here does not match the service docs procedure which is in fact even more complex. I initially thought it just stated to disconnect the battery, wait and reconnect.

I keep being told I need to follow the reset procedure precisely. I have now done that exactly to the letter. I mentioned that. What I also mentioned and not sure if it was been missed because it was a long post is that according to the docs the procedure is actually even more complex than what is being posted around. Are the docs wrong? and if they are right and precision is the key why are the commonly posted and reposted reset instructions missing important steps. That is what I'm getting at as it sounds completely at odds.

Anyway the only reason I asked is because I was on the cusp of buying a lexia anyway as I thought that would be the next logical step. I'd already searched the web to death downloaded and scoured all the docs and not found the answer. Time will tell when it gets here and I still hope I can fix it and post the answer to help anyone in future who may get the same issue.

[Hell Razor5543]

Definitely get a Lexia, but make sure you get one that can connect to your car. Some of the clones use an older chipset that cannot work with Diagbox over version 5.29. A company called Easy Diagnostics do a good one, and will talk to you when taking the order, and not just to ask for your credit card number.

[uglybanana]

My lexia arrived today and was happy and relieved to see it worked straight away on Windows 7 64bit. The global test came up with a few stored faults. Some related to when my brake switch came loose after not connecting it back in properly after testing which threw up ABS, parking brake fault etc. P1351 for glow plugs/relay. A rain sensor fault but I fixed that with a missing fuse. I cleared all the faults and now I just have 2 returning faults.

F8EB which is no permanent + to multi-function display. Can't find much info on this but doesn't seem to be anything major. Display works fine.
U2005 triggering vehicle speed anomaly from the suspension ECU. Possible ghost fault from what I have read on here or could this be why the cruise isn't coming on due to faulty speed info?

I did a live function test on all the steering wheel buttons. Everything responded to the button presses so the buttons themselves are ok. I also tested the glow plug relay with the actuator test and could hear it clicking so it's probably the plugs. I need to get a multimeter on those to confirm but that isn't going to cut out the cruise control. I checked the turbo pressure against the reference value. I've read problems here could mean a faulty electrovalve which could stop cruise from working but it seems to be more or less in line with the reference values. I tested the electrovalve with the actuator test as I felt for vibrations as advised in diagbox and it seems to be working.

Just wondering if anyone can advise what to check next to narrow down the cruise problem? Definitely worth getting the kit though as I didn't even realize the rain sensor was faulty as I haven't had the car long and it shows the DPF was recently changed and in good condition and Eolys looks to be at a good level for the mileage on the car.

[Hell Razor5543]

If you are going to test the glow plugs the best way (if you can get them out intact) is to power them up. A glow plug should glow at the tip to be effective, but a failed one can go open circuit, or glow part the way along the element. Using a multi meter will only show if there is a circuit or not.

First, be VERY aware that when it has power the glow plug gets VERY hot, so make sure there is nothing flammable nearby, and be careful when handling them afterwards. Mount it in a vice, touch the negative lead of a battery to the earth body of the glow plug, and then the positive lead to the positive feed of the glow plug. The tip should start to glow very quickly.

I know of a few people who have tried this test and found that one or more of their plugs have been faulty (one person had 3 failed plugs, even though 2 did power up, but not at the tip), and when they replaced them the engines would start more quickly in cold conditions.

[GiveMeABreak]

The U2005 can usually be ignored if you don't have a V6 X7, as only these models have the additional suspension ECU (CSS). I had this confirmed as a known ghost by the main dealers after sending these of for comment by the Service Manager.

I'm sure there are some live tests you can run on the speed regulation system - but you'll need to do these on a drive to see if it will throw anything up when trying to activate and set speed limits etc., whilst on the move.

[GiveMeABreak]

If you are going to test the glow plugs the best way (if you can get them out intact) is to power them up. A glow plug should glow at the tip to be effective, but a failed one can go open circuit, or glow part the way along the element. Using a multi meter will only show if there is a circuit or not.

First, be VERY aware that when it has power the glow plug gets VERY hot, so make sure there is nothing flammable nearby, and be careful when handling them afterwards. Mount it in a vice, touch the negative lead of a battery to the earth body of the glow plug, and then the positive lead to the positive feed of the glow plug. The tip should start to glow very quickly.

I know of a few people who have tried this test and found that one or more of their plugs have been faulty (one person had 3 failed plugs, even though 2 did power up, but not at the tip), and when they replaced them the engines would start more quickly in cold conditions.

Aside from the useful advice here James on testing the plugs - would these actually affect the speed limiter / cruise functions though? Unless I'm mistake the glow plugs are only operational under cold conditions?

[Hell Razor5543]

Just a thought (may be a red herring, might be worth a check). You have got the brake switch correctly back into place (and properly lined up), haven't you? On my C5 Mk1 it has one switch body that has two switches within it; 1 push-to-make switch for the brake lights, 1 push-to-break switch to disconnect the cruise control. If the switch had come off (causing the ABS issue), and not been put back properly, it might be that it is pressed just enough that any engine vibration might momentary trip the push-to-break switch, disconnecting the cruise control.

I would guess (but that is a GUESS!)that about 5mm travel on the brake pedal before the brake lights came on might also clear up this possibility.