Finally admit defeat C5 2.0 HDI - someone help!

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Hell Razor5543
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Re: Finally admit defeat C5 2.0 HDI - someone help!

Post by Hell Razor5543 »

If you were to post the vehicle VIN here it would allow those with the relevant access to determine much more about the vehicle, which would help with the error codes. The VIN will be automatically obscured, so only forum staff can read it (like this, for example; VF7**************[VIN obfuscated, can be read by forum staff] ).

mark6535
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Re: Finally admit defeat C5 2.0 HDI - someone help!

Post by mark6535 »

2010 RHH engine, in a C5 estate.

I'm new to the whole Diagbox software but have experience using Jaltest/eclipse on HGV's, so I'm sure I'm using it correctly. It's just annoying how I can have either turbo position and repeat signal values in sync...but overboosting.....or required boost and measured boost pressures working in sync but turbo position values out and "not enough turbo" warning 😭
Tried 2 different solenoids, 2 MAP sensors. It's a basic system I just don't get it.

I'm confident the turbo is fine as it's been tested. I'm confident the repeat sensor is fine as I've tested it. MAP and boost solenoid swapped.
So I'll vacuum test it today but failing that my next step is take the wiring harness out and check it over and test it.

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Re: Finally admit defeat C5 2.0 HDI - someone help!

Post by mark6535 »

VIN number is VF7**************[VIN obfuscated, can be read by forum staff]

Thanks for your help so far guys.

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bobins
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Re: Finally admit defeat C5 2.0 HDI - someone help!

Post by bobins »

For the avoidance of doubt, as far as you know, are the intake and exhaust systems entirely stock and not been 'got at' ? DPF and EGR as they left the factory ?

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Re: Finally admit defeat C5 2.0 HDI - someone help!

Post by mark6535 »

Yes are far as I'm aware, intake looks standard, the pre cat on the back of the turbo I checked when the engine was out, and the dpf fitted doesn't have any tell tale weld marks on it.

I should probably add, I've owned this car for a year. It was bought from a co-part auction with minor front end damage (bonnet, bumper, both headlights) which I replaced.
I bought this with 154,000 miles on and now currently has 163,900.

mark6535
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Re: Finally admit defeat C5 2.0 HDI - someone help!

Post by mark6535 »

Right I give up, I borrowed my mates identical car. Checked voltages on boost solenoid/MAP/MAF plugs both disconnected and connected. Checked with a vacuum gauge for pump vacuum, vacuum on the vacuum circuit as well as what it's pulling on the turbo actuator...everything is exactly the same on both cars. I even swapped solenoid/MAP/MAF and still the same.

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KennyW
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Re: Finally admit defeat C5 2.0 HDI - someone help!

Post by KennyW »

What is your RP no as from 12292 there was a change the vacuum pipes for the electro solenoid valves at the rear of the engine. Also the number of valves went from 4 to 3.

I had a similar problem and I changed 2 valves and 2 vacuum pipes and the MAF sensor. The fault has not reappeared so far.

Kenny

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bobins
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Re: Finally admit defeat C5 2.0 HDI - someone help!

Post by bobins »

I'm starting to wonder if the DPF is blocked but has somehow been bypassed in the ECU/BSI so it doesn't throw a fault. I've just replaced the cat on my pick-up truck as it was blocked and would give a sound possibly similar to your "sounds like a diesel supra (pssst...tutututu)" and "it still sounds like a petrol with a blow off valve" you mentioned. My truck was blowing from the manifold to downpipe joint - I could feel the exhaust blowing by on the joint but only when I revved it. If your C5 is still on the original DPF at 163k then it could be blocked, but should show a fault unless a previous owner has got creative and somehow bypassed the software.

Anyone out there know if it's possible to somehow 'delete' the DPF warning side of things ?

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Re: Finally admit defeat C5 2.0 HDI - someone help!

Post by mark6535 »

I THINk I'VE SUSSED IT!!!! (Kind of)
So...whilst on Diagbox, and under standard parameters...the only 2 that were fighting each other was measured turbo pressure Vs turbo signal repeat. All other actuator tests showed everything to be ok. But whilst I had my mates car with me I was tinkering around and realised when his was idling the "actuator for egr cooler bypass" was retracted...whereas mine wasn't.
I had no vacuum comming out of that solenoid...so I swapped his solenoid for mine....still the same, except this time when I went through actuator tests, the one for egr cooler bypass failed with the fault "soiled actuator"

The one on my car has a 3 wire plug comming from it, his doesn't.

So does anyone have any idea about how this system works? What signal is needed to energise the solenoid? I can see that this actuator is a 2 in 1. Functioning actuator as well as a little magnet on the back to relay position.

If anyone has any info it would be greatly appreciated

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Re: Finally admit defeat C5 2.0 HDI - someone help!

Post by Hell Razor5543 »

I would check the vacuum pipes first. If there is a leak that would stop the EGR from working. The next thing you could do is check the vacuum pipes are the right way around. On my previous C5 she had problems that I could not solve. Her current owner (who knows a lot more about Citroens then I) found that the two pipes to the EGR electrovalve were fitted the wrong way around (what really irritated me is that a garage had replaced both the EGR valve and the related electrovavlve, as they were supposed to be faulty). Finally (if the previous suggestions have not worked) you could try is to swap the connectors and pipes between the electrovalves (but make sure you know which way around everything goes, so you can put them back the right way afterwards). You will have two, close together. One is for the EGR valve (Exhaust Gas Recycling Valve), and the other is for the Turbo, and they should be identical valves. If you swap the pipes and connectors across, and the EGR starts working, you know you probably have a faulty electrovalve.

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Re: Finally admit defeat C5 2.0 HDI - someone help!

Post by mark6535 »

I'll give that a go. I have tried swapping them with the other car, and the pipes are so bloody short on the egr solenoid it's hard enough getting them on right 😂😂 Also, my car has the double air doser, with both plugged in and both with vacuum hoses attached...but..the plastic pipe from turbo to doser...where it branches from one pipe to 2 pipes...it's sealed up..as in bonded from factory.
Is this supposed to be like that?

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bobins
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Re: Finally admit defeat C5 2.0 HDI - someone help!

Post by bobins »

I have a feeling yours will be around the cusp of when it changed from one working doser to two. I remember reading on here several years ago about someone who worked out they had two dosers but only one was plumbed in and working from the factory.

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Re: Finally admit defeat C5 2.0 HDI - someone help!

Post by mark6535 »

Ahh, I did Google and it brought up a post on here but I wasn't sure. Seeing as the car was from auction anything could happen 😂😂
From what I've read and what I know from my job, the egr being internally faulty (if I use vacuum pump to pull up the actuator the revs or engine behaviour doesn't change) this can stop the ECU sending a signal to the egr control solenoid. I've ordered a new egr...have to see what happens.
There really isn't a lot of info in the terms of wiring diagrams and schematics available is there for Citroens. If this were a hgv I would have a full system diagram working illustration showing all inputs and components on the intake/exhaust circuit

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bobins
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Re: Finally admit defeat C5 2.0 HDI - someone help!

Post by bobins »

Send Marc - GiveMeABreak - a PM with your wiring and schematics request and see what he can come up with for a donation to the forum :)

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Re: Finally admit defeat C5 2.0 HDI - someone help!

Post by KennyW »

Mark6535

When I had my problems I drew up my own basic diagram for the solenoids and vacuum pipes.

There are diagrams out there but depending on your RP no will dictate your lay out.

Kenny

Here's a link to my problem which started of as dpf blocked.

viewtopic.php?p=642109#p642109