Member Since: 16 Feb 2017
Location: Kelso
Posts: 200
Changed Low Pressure Fuel Pump & now have HDC/Gearbox fault
Changed Low Pressure Fuel Pump & now have HDC/Gearbox fault!
Had the car lifted off the ground on 2 post ramp, fixed LPFP, car starts and runs fine and now within 10 seconds of the car getting started we have a HDC and Gearbox fault.
Has anyone any ideas, ran diagnostics and had a load of U codes which I have cleared, but within 10 seconds of starting the car the gearbox and HDC faults come back on.
23rd Sep 2018 7:14 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4626
Sounds like something did not go back right when changing the pump. Did you change the filter as well?yµ (idµ - eAµ) ψ=mψ
23rd Sep 2018 7:52 pm
jeep948
Member Since: 16 Feb 2017
Location: Kelso
Posts: 200
I had it all up and running fine but the float level was sticking so I stripped it all back off today, I am wondering if it’s anything to do with the suspension that’s causing the issue as it stuck in off road mode initially but sorted itself out after a few minutes. I did the filter before the pump.
23rd Sep 2018 8:07 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4626
Its not unusual for the suspension to behave oddly after having the wheels raised off the ground and usually resets pretty quickly. If you had a susp issue there would be DTC to support that! What codes are you getting when the U codes are cleared? Also is your filter the twist on type and aligned correctly? Is it a genuine quality filter?yµ (idµ - eAµ) ψ=mψ
23rd Sep 2018 8:20 pm
jeep948
Member Since: 16 Feb 2017
Location: Kelso
Posts: 200
Yes the filter is original one, as I said I had the tank off and the filter replaced about a week ago and it’s ran fine, the only reason I had it off again was as the float was not in correctly so was giving an incorrect reading. The codes I am getting just now are U0401, U0402, U0416, U2023.
23rd Sep 2018 8:27 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4626
Have you read all modules? The LPFP has no diagnostic evaluation itself as that occurs further down the fuel system. By the way what diagnostic tool are you using?yµ (idµ - eAµ) ψ=mψ
23rd Sep 2018 8:39 pm
jeep948
Member Since: 16 Feb 2017
Location: Kelso
Posts: 200
I am using a snap on solus pro, I am not thinking it has anything at all to do with the lpfp, I am thinking it has something to do with me lifting the car off the ground with the 2 post ramp perhaps.
23rd Sep 2018 8:42 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4626
I use a 2 post ramp daily on D3/4s with no issues. That said its not beyond the bounds of possibility that something has been disturbed. I assume you are able to read all the control modules but if not a dedicated tool might be needed. GAP, ICarsoft. U codes are vague at best and can often be a cascade. For now I can only suggest you go over all the relevant connectors at each wheel but don't unplug any of the height sensors.yµ (idµ - eAµ) ψ=mψ
23rd Sep 2018 8:53 pm
jeep948
Member Since: 16 Feb 2017
Location: Kelso
Posts: 200
I will check everything again this morning and see if I have disturbed something whilst doing what I did yesterday. I assume that disconnecting the sensors causes further issues?
I agree with PROFSR G, sounds like a sticky or faulty height sensor.
Flack
24th Sep 2018 8:56 am
jeep948
Member Since: 16 Feb 2017
Location: Kelso
Posts: 200
I have just replaced 2 of them in the last 2 weeks, nothing showing on the machine reference the sensors though, my only thought with regards to this perhaps I caught the OSR one as I connected one of the fuel pipes back together.
24th Sep 2018 9:14 am
jeep948
Member Since: 16 Feb 2017
Location: Kelso
Posts: 200
UPDATE
Now just rescanned and I have p0088 fuel rail/system pressure - too high.
As I had stated earlier in the thread I have dropped the tanks and repositioned the float sendor as it was not reading correctly.
Is it possible that I have kinked a fuel pipe or something and all of this is caused by doing so??
24th Sep 2018 10:15 am
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4626
It looks like "maybe" something did not go back quite right with that code if it wasn't there before. I suppose there's only one way to find out yµ (idµ - eAµ) ψ=mψ
24th Sep 2018 12:35 pm
KostasA
Member Since: 23 Aug 2015
Location: nairobi
Posts: 286
fuel rail pressure is on the high pressure side, which means that LPFP has nothing to do. Either a problem with HPFP (or the valve that it has) or maybe your sensor, the one on the fuel rail, is gone.
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