 | Home > Puma (Tdci) > Help needed – Defender TD4 stopped after VCV replacement |
 
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| andy63 Member Since: 30 Jun 2023 Location: north east Posts: 785  
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Reading your post a few points come to mind..
What was the original fault code..?? Did you confirm no fuel delivery from hp pump by checking the rail pressure.. You could do a few basic checks on the vcv.. ie is their resistance ie continuity across the pins..can you hear it clicking when 12v applied.. Check there is a voltage been applied when ignition is on... You should be able to bleed fuel through to the hp pump with a little bulb type pump.. either connected to the connection under the normally green cap on the lp fuel line , but you will need a connector which will open the schrader valve, or get fittings that allow you to break a coupling on the lp fuel line, in the same location as the point I've mentioned.. |
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7th Jul 2025 8:33am |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17851 
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It should not be necessary to conduct any bleeding operations after changing the VCV (nor for that matter any of the HP fuel system - the HP side is self-bleeding and the official WSM makes no mention of bleeding the HP side).
The bleeding procedure is only relevant to the low pressure side since the LP side of the mechanical fuel pump cannot self-prime from the tank if there is significant air in the system. It would be useful to know what the original falt code was and the symptoms which resulted in you changing the VCV. It is extremely rare for a faulty VCV to cause any fault codes (usually it is the absence of a fault code which points to the VCV). It is very difficult to provide diagnostic advice without all the background (I realise that you asked about the bleeding procedure and not specifically for diagnostic advice). I would recommend that as a first step you use a diagnostic tool to see what fuel rail pressure you get whilst cranking. If you are getting no pressure or very low pressure, I suggest checking the crankshaft and camshaft position sensors' outputs (the ECM won't attempt to fuel the engine without valid signals from both sensors), then the VCV input wiring and the VCV itself. The fact that you've changed the VCV makes the new one an obvious suspect (and note that there are many rubbish and counterfeit Denso VCVs on the market - where did you get yours, what make is it)? As a matter of note it should also be entirely unnecessary to jack up the back of the vehicle after changing the fuel filter. If you fill the new filter with diesel before fitting, the LP system will self-bleed the minute amounts of air that remain. |
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7th Jul 2025 11:01am |
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| irishhawk11 Member Since: 07 Mar 2022 Location: Feldkirch Posts: 21  
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Thank you guys for your fast reply.
I sadly only have this picture with text in german as I am located in Austria but the Error-Code may help. Anyways, what I didn't mention was that I disconnected the fuel supply line to gain better access as I removed the intake manifold to gain better access to the VCV. What I find strange, if it would be air - why did it "come" into the system after ~100km? Maybe because of uphill driving? @andy: If I understand you correctly - check the voltage at the two pins when ignition is on? VCV used: https://www.auto-doc.at/ridex/14347923 Sry for the "glare"  Click image to enlarge Regards Benjamin |
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7th Jul 2025 11:55am |
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| BrickBox Member Since: 05 Oct 2021 Location: Wales Posts: 1003  
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Unfortunately the 2.4 is a bit of a pain if you get air in the system. It takes a good effort to get it running again. You just have to have persistence. Once it starts, don’t Rev the engine etc - you have to leave it try and idle.
You may find one of these useful- but you’ll have to get the Ford fuel fitting for the lines. https://www.halfords.com/tools/garage-equi...48QAvD_BwE Failing that - air can mess the HPFP up. 2008 2.4 110 Utility Station Wagon XS. |
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7th Jul 2025 12:27pm |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17851
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The picture is fine! Were these the faults present before the VCV was changed? The first two are not likely to be important and are merely saying that the pump and injector learning cycles have not been successfully carried out:
P268B00 - High pressure fuel pump calibration not learned/programmed The third one is more interesting and points to an electrical failure (or possible sensor failure) related to the high-pressure fuel rail pressure sensor:
This I imagine could cause the engine to fail to run, I am not sure what the ECM does if it thinks it cannot monitor the fuel rail pressure, it may go into a default mode and run with a fixed VCV modulation or (perhaps more likely) it may simply stop fuelling altogether. If the fuel rail pressure sensor has failed or the wiring has failed you will not see any reliable pressure reading when cranking (it would be worth seeing what it is saying though) and I would suggest investigating the wiring and the sensor as a next step. Last edited by blackwolf on 9th Jul 2025 3:32pm. Edited 1 time in total |
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7th Jul 2025 12:59pm |
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| andy63 Member Since: 30 Jun 2023 Location: north east Posts: 785
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Your initial description of stopping suddenly does not indicate an air in fuel issue..
I can't find definite answers for your specific fault codes but the first two are landrover specific and possibly relate to an injector issue on a cylinder.. The last one is generic and possibly an electrical issue with the rail sensor.. When I said check the voltage with the ignition on I mean probe the connector with the red multimeter lead with the common lead on a good ground...and on voltage scale.. You should see battery voltage on one possibly both pins..I think the vcv is ground switched by the ecu to alter its time on..ie duty cycle.. I know when my engine is running that the vcv voltage is a 15v supply but that's a 2.2 tdci engine.. |
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7th Jul 2025 1:05pm |
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| irishhawk11 Member Since: 07 Mar 2022 Location: Feldkirch Posts: 21
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Thank you for your replies.
@blackwolf: Yes, these error messages were present before and when deleting the errors the engine makes a short <1s stutter, but it doesn't make any improvement. The faults return after every reignition/restart. The last error message P019015 also puzzles me. I hope that this is only due to the fact that I opened the high pressure line to check if there is pressure/fuel reaching the rail. Otherwise I need to consider other fault... My next steps: -New Fuelfitler (Pre-filled) -Bleed fuel system with bleeding kit (See pic) -Reconenct system and try restarting -Read common rail pressure -Otherwise check voltage on VCV and Fuelpressuresensor with Volt Meter Click image to enlarge |
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7th Jul 2025 1:44pm |
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| andy63 Member Since: 30 Jun 2023 Location: north east Posts: 785
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If you need to check your rail pressure sensor , and its similar to my 2.2 tdci then you can expect to see around 1v output at tick over.. rising to around 2.5v when you blip the accelerator..that's no load figures..on the signal wire..
Click image to enlarge It will have a 5v supply and a ground as well which could be checked |
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7th Jul 2025 1:54pm |
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| irishhawk11 Member Since: 07 Mar 2022 Location: Feldkirch Posts: 21
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A question. Do you think it could be an Immobiliser issue, that the 10AS System is blocking the engine to restart?
https://www.defender2.net/forum/topic91943...otor+start |
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7th Jul 2025 3:01pm |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17851
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But presumably you didn't fiddle with the fuel lines until after the fault had been logged? An immobiliser issue could cause a non-starting problem but would not cause the P019015 error. I do not think that the immobiliser is a factor in this case. I strongly recommend checking the wiring for the sensor. LR states that the sensor is not a separate service part and can only be replaced as an assembly with the fuel rail. |
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7th Jul 2025 4:10pm |
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| custom90 Member Since: 21 Jan 2010 Location: South West, England. Posts: 20910
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I’d manually record the DTC(s) and erase them, and disconnect the battery for a while.
Then see what happens if anything. Was the old VCV really bad? Presuming so, and you could have had a duff new one out of the box. When I fitted mine, it went in fine, started and idled all was fine with it. As Blackwolf explained in depth there shouldn’t have been any need to bleed or anything like that. Did you follow the WSM procedure for fitting it and the torque settings for it? Anything stopping it sealing could be some issue, such as an air leak or faulty seal and installation needs to be very clean. If I recall correctly cleanliness is mentioned in the WSM when fitting as these items are very sensitive to and contamination as it’s after fuel filtration. _\Hennessey|Venom| F5/___ ___\⭐️Lone|Star|State/___ ____\We|Will|Win/___ ____/🇬🇧🇺🇸\____ _//*⛽️🛢️⚙️🧰*\\_ |
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7th Jul 2025 10:34pm |
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| Esben Kold Member Since: 14 Oct 2023 Location: Horsens Posts: 40  
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I have been through most of the problems people seem to encounter with both the active and the passive immobilizer. I never had any really odd or unrelated faults, so I do not think that this should be a priority at this point. |
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8th Jul 2025 5:33pm |
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| HardCharger Member Since: 03 Mar 2013 Location: Manila Posts: 778  
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Check and make sure all the fuel fittings you removed to do the job were properly returned. If one of them aren't properly returned, it could be the source of the air ingress into the system. No Better Friend, No Worse Enemy
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9th Jul 2025 3:40am |
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| irishhawk11 Member Since: 07 Mar 2022 Location: Feldkirch Posts: 21
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Hello again,
yes, prior assembling the VCV I disconnected the fuel supply line, that is why I think during the incline the air made its way trough to the front... But then again, it doesn't make sense after ~100km. To the error-message P019015 - Fuel rail pressure sensor A circuit --> Is it possible the the pressure valve released? I read that this needs to be replaced when the valve is triggered. --> or could this failure be because I opened them middle valve of the fuel rail to check if fuel is coming, which wasn't the case...? The old VCV wasn't that bad but after the replacement the idle rpm it was significantly more stable and strangely some rumble when fully accelerating at lower rpm in 5th/6th gear improved. |
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9th Jul 2025 1:58pm |
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