PGrehan

I received part 1920QR and fitted it last night. The engine check light remained on. I checked again this morning and the light remained on. I drove it about 25 miles, parked it up and when I returned shortly afterward and started her up, the engine check light remained off this time (apart from the normal few seconds lighting up at the start). I've since had a few more starts and the light has remained off. At this point it's looking like the problem is resolved. Thanks to those who posted offering advise - it was very helpful.

To the Judge and Paul R, thank you for your replies. I've located the sensor part no 1920QR. I removed it to see if there was an obvious blockage, but there was not. I was surprised to see that the part of it that was inserted in the path of the intake airflow was coated with an oily film, but maybe that's normal. I guess that the exhaust gas recirc air could be the cause of this. Anyway, unfortunately the code reader that I have is pretty basic, and only reads the codes. It will not display live data, so I can't do any further diagnosis. I decided to take a flyer and buy a replacement sensor 1920QR - hopefully the replacement will sort it out, but I won't know until later in the week or worst case next week. I'll let you know what happens. Thanks again.

I had the engine check light on the instrument panel light up on Thursday morning, and has not gone out since. I've driven it about 150 miles since and it seems to be driving as normal despite this. I bought a basic EOBD code reader which indicates fault code p0235 (Turbocharger Boost Sensor A Circuit Malfunction). I'm not sure where this sensor is in the engine bay. I'd be grateful if anyone familiar with this could describe where to find it. From what I can find on the net, root cause is likely to be split tubing feeding pressure signal to sensor, faulty sensor itself or faulty wiring to sensor. Has anyone on this forum experienced similar issue, and if so what was the route cause in that case? Thanks in advance.

In the end I didn't swap the front wheels to the rear axle and vice versa. The fitter at the garage where I took the car for new tyres noted that the outer blocks had "irregular wear" (for more info on this, see link below), and that this may result in annoying tyre noise that would be likely more acute and annoying on the front axle. While I was not that familiar with this phenomenon, I vaguely recalled hearing something about this before, and as it happened I had noted some noise recently while driving that I was attributing as an early sign of wheel bearing wear. http://www.continental-tires.com/car/technology/tire-knowledge/lex-1-3-1 The majority of my driving is on long motorway journeys at constant speed, which does correspond to one of the explanations for why this issue occurs per the link. Anyway, I decided to put the new tyres on the front axle and leave the rear tyres on the rear axle for the moment; I shall replace the rear tyres shortly. So, unfortunately I can't tell you for sure whether moving the wheels around the car would have caused issues with the tyre pressure monitoring system on the car.

Thank you for your reply, Mike. Since I made the original post I've had a few searches on Google to see if I could find out a definitive answer. Unfortunately I've not found anything official. There's nothing I could find in the hand book. I found the link below https://www.frenchcarforum.co.uk/forum/viewtopic.php?t=37728 There's a post from Wheeler near the end of the above link which describes how the C5 mkII system works, and if correct would suggest that the car can "re-learn" the location of the rotated sensors on the car. There are posts that suggest that a Lexia would be needed too. I guess I'm going to find out which are right, as I'm scheduled to have the front tyres changed and moved to the back on Friday. I'll let you know what happens. Thanks again.

Hello all. I have a 2011 Citroen C5 mk2 fitted with tyre pressure monitors. As the front tyres are near worn to limit but the rear tyres are OK, I want to move the rear wheels/tyres to the front and then replace the worn tyres and fit the new tyres on the rear axle. I'm presuming that the tyre pressure sensor monitors fitted to each wheel are not location specific, and can be moved from one corner to another without problems, but I'd be grateful if anyone can confirm this. I did a quick search through the forum to see if this question had already been answered, but did not find an answer - my apologies if I missed it. Thanks in advance.

With the vehicle stopped, I put the tube of hand cream between gear stick and electric hand brake lever and pulled back the gear stick; sure enough, the movement of the gearstick forced the end of the tube onto the edge of the hand brake lever and lifted it up (I took a picture but I can seem to upload it). Based on this, I think that this is likely the cause of what occurred. I wish I'd looked down to the gear lever when it happened, but when the car suddenly slowed down on me my first thought was that I'd accidentally selected the wrong gear, and after trying again my thoughts moved on to the engine or clutch being the issue. Thanks to everyone for their replies to my post.

Thanks for your recent replies, Mike & Paul. I think that you may be closer to the truth with your suggestions about the electric handbrake. I tried applying the electric handbrake while moving a few days ago, and the resulting braking sensation was similar to what I remember from a week ago. Since the electric hand brake will not stay applied when vehicle is moving, as soon as I let it go it released. I rarely leave any bits & pieces on the centre console around the gearstick, but as it happens I had a tube of hand cream sitting there last week. I'm thinking that what may have happened is that as I pulled the gear lever back into 4th or 6th, the tube sitting between the leather lever gaiter and hand brake lever got pushed back thus activating the hand brake. Admittedly the above is only a guess as to the cause, but it is at least consistent with problem occurring only when pulling gear lever toward back of car - the fact that it did not occur when going into 2nd could be explained by the tube being on right hand side of lever. The problem ending after a few minutes could be due to the tube moving after the number of gear changes that I performed at the time. Anyway, I'll pick up the hand cream from work tomorrow and see if I can find a position between gear lever and hand brake lever such that I can reproduce the above.

Thank you for taking the time to reply, and for the welcome. Firstly, since yesterday the problem has not recurred. I've driven to work this morning, and since have driven about 120 motorway miles (6th gear virtually all the way) without issue. I haven't noticed any unusual noises from brakes, engine or gearbox since the problem went away. The car is a 2011 X7 model; I referred to it as a Mk II earlier, but perhaps I should have referred to it as a Mk III? There was no passenger in the car at the time the problem occurred. I can say it was definitely gear related to the extent that it was limited to when gear selector was moved to 4th or 6th position. I can't say with certainty at what speed the problem occurred at; it was likely between 30 and 55mph, but I couldn't swear to that. The speedo is working fine, and I think it was working fine during the time the problem was happening, but I wasn't focussing on that at the time so again, I can't be sure. I an be sure that depressing the clutch pedal wasn't the cause, as problem would only occurred after gear selector moved to either 4th or 6th position. I know I have said that the car "braked" on selection of 4th or 6th, but whether it was the brakes or something else that caused it is open to question. It felt like the engine breaking that happens when you accidentally select 2nd gear when you intended to select a much higher gear. It's a bit of a weird one, I agree. Given that it was -1 celcius when it happened, I'm thinking that it could be related to ice melting causing a temporary malfunction somewhere, but I may be clutching at straws. I shall try and move the gaiter around the gear lever and see if any wiring is being disturbed, as suggested by paul.h. I presume it just unclips from the base. If it occurs again I'll keep you posted. Thanks again.

New to this forum, so hope that you may be able to help. I left for work this morming, and drove from cold for approx. 6 minutes (approx. 3 miles travelled) with no problem, and then tried to engage 4th gear. When I did this the car slowed down as if brakes had been applied. I immediately disengaged 4th and went back into 3rd - 3rd gear worked normally. I tried engaging 4th again but had the same problem. I noted that the braking would occur once gear lever was put into 4th gear position even with clutch fully depressed, which would indicate to me that the braking is not due to engine braking but more likely due to brakes being applied (to be clear, I did not apply the brakes myself). Anyway, to cut a long story short, the problem also occurred in 6th gear as well (but not 1st, 2nd, 3rd and 5th) . After driving for a few minutes with this problem, it then stopped happening. Ambient temp outside was -1 celcius. Problem did not recur when I drove the car later on, or when driving home tonight. I rang the dealer that sold the car to me. He checked the Citroen database but found no history of problems similar to this one. The car is a Citroen C5 Mk Ii (X7) with 2.0 160hp diesel engine, 6 speed manual gearbox and hydractive suspension. My concern is that it could happen again, and a car travelling behind could run into the back as a result. If anyone has experience similar to this, I'd be grateful if you let me know if/how the problem was resolved. Thanks in advance.