Ok, this is an intermittent problem that’s becoming less intermittent! If I drive the Freelander out 20 mins or so & park up, when I come to start it again the EML is on and there is no response from the throttle pedal.

The codes that seem to pop up are:
P0220 Throttle pedal B track PGS (0x0220)
P0641 Sensor supply voltage 1 (0x1E55)

There are 2 other codes present -
P0100 airflow meter sensor malfunction(0x0100) &
P0235 boost pressure sensor malfunction (0x0235), but it’s got a blanked EGR so I’m assuming these relate to that. They don’t cause the EML to come on at any rate!

What I’ve done so far - changed the throttle pedal, so I know it’s not the throttle sensor.

Wired the fuel rail pressure sensor directly to the ECU (the wiring & plug was in a bad way and connected to some sort of mapping box - 8 little toggle switches and number 4 was on. All that’s gone now.

Pulled the fuel pressure regulator down by the starter motor and replaced all the o-rings washers.

Anyone have any other ideas?? Do I need to be replacing fuel rail sensor or pressure regulator (please no, that was a pain!) completely?

All help gratefully received!
 
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P0220 Throttle pedal B track PGS (0x0220)
P0641 Sensor supply voltage 1 (0x1E55)

poss no supply voltage to throttle pedal.
Poss causing the other faults.
Can you get live data to check at point of fault?
 
I haven’t checked voltage to the pedal but I have looked at ecu data while the fault is live and seen the demand from the pedal registering, both on track A & B, but nothing happens to the engine revs. That seems to suggest the pedal and the data connections to the ecu are not the trouble, and I can’t for the life of me figure out why the problem disappears when the engine goes cold.
 
Hmm..mine’s a manual td4 & no cruise control. Probably the same wiring loom though. I will try and check that nothing else has been wired into it for a power feed or something, thanks for the ideas!
 
That does suggest the ecu is getting good pedal signal.
What about other live data at fault, the sensor supply voltage is drawing me in.
 
FWIW ..

i did hear an account of a mysterious issue on another make of vehicle
it ran fine when cold .. but had major issues when warmed up ..
owner took it to garages .. no luck ..
he finaly took it to an electrician ..
issue turned out to be a wiring fault ..
i.e. something expanded when warm .. breaking the circuit ..
but was ok when cold ..

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ok, drove it around for a while this morning on the school run then plugged the magic box in. I was hoping to get some 'good' data to compare with the fault, but the engine went to idling not long after and I had to limp home! I did at least get some data with the fault live...
data3.jpg data1.jpg data2.jpg


Two things I noticed - first off 'sensor 1' is showing as 4.99V...which makes me wonder if the issue is it's dropped below 5V triggering the fault code...especially as sensor 2 is at 5.35V. Dumb question time - are sensors 1 & 2 the throttle demand sensors or something completely different?

Secondly the throttle demand sensor - when I put it to the floor the ECU read that as 3.98% & 4.4% for pedal 1 & 2 respectively...is that normal?
 
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Secondly the throttle demand sensor - when I put it to the floor the ECU read that as 3.98% & 4.4% for pedal 1 & 2 respectively...is that normal?

see attached jpg :
gopedal.jpg

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but the engine went to idling not long after and I had to limp home!
i was under the impression to engine wouldn't rev at all .. off idle ..
so it is drivable .. somewhat ?

re my prev post with pic.
be the .pdf download on first post here :
https://www.landyzone.co.uk/land-rover/freelander-td4-m47r-manual.296006/

note : in that pdf .. the low fuel pressure system relates to older vehicles
i.e. that have a lift pump inside the fuel tank ..
and the turbo description be the non-vnt type .. with a 'waste-gate' ..
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i've no idea what sensors '1' and '2' are in the pics of scans ..
that pdf has some info re voltage for sensors
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btw: when the engine goes limp .. after it warms up ..
it's can be an indication of a too low fuel pressure in the high pressure system
e.g. a faulty injector / high pressure pump ..
( that usually brings up a P1190 code )
when you restart it when warm .. does it take much cranking on 'start-up' ??

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there's a fault-finding .pdf here .. as a download ..
https://www.landyzone.co.uk/land-rover/75-zt-td4-fault-diagnosis.203935/
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i was under the impression to engine wouldn't rev at all .. off idle ..
so it is drivable .. somewhat ?


btw: when the engine goes limp .. after it warms up ..
it's can be an indication of a too low fuel pressure in the high pressure system
e.g. a faulty injector / high pressure pump ..
( that usually brings up a P1190 code )
when you restart it when warm .. does it take much cranking on 'start-up' ??


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
there's a fault-finding .pdf here .. as a download ..
https://www.landyzone.co.uk/land-rover/75-zt-td4-fault-diagnosis.203935/
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

It's only 'drivable' due to the miracle that is effortless diesel torque;)
On the flat I can get 'er into 5th and do about 20-25mph on idling revs, she'll handle a modest incline in 3rd and pretty steep hill in 1st (I live at the top of one!)...though I'll admit at that point it'd be quicker to walk!

My first thought was fuel pressure, that's why I started with the rail connection to the ecu & the pressure regulator washers. That one was a bugger but she now starts a hell of a lot easier!

Its early days but it MAY be the MAF...I just pulled the MAF connector and she'll rev now...it's always tough with an intermittent fault but I didn't expect it to be able to rev yet. Next step is replace the MAF and then wait and see!

Thanks for the all the other resources too!
 
It's only 'drivable' due to the miracle that is effortless diesel torque;)
On the flat I can get 'er into 5th and do about 20-25mph on idling revs, she'll handle a modest incline in 3rd and pretty steep hill in 1st (I live at the top of one!)...though I'll admit at that point it'd be quicker to walk!

My first thought was fuel pressure, that's why I started with the rail connection to the ecu & the pressure regulator washers. That one was a bugger but she now starts a hell of a lot easier!

Its early days but it MAY be the MAF...I just pulled the MAF connector and she'll rev now...it's always tough with an intermittent fault but I didn't expect it to be able to rev yet. Next step is replace the MAF and then wait and see!

Thanks for the all the other resources too!
Dunno how much a MAF sensor is, but there doesn't appear to be any (major) problems running with the MAF disconnected - so I'd give it a while and see if it affects anything before splashing cash.
 
Thanks.
90% sure its the MAF sensor - I reconnected everything and went on the school run this afternoon - fault reoccurred - I had put the tools in the boot just in case, popped the bonnet & pulled the MAF connector and hey-presto! Engine revs again. I suppose I did also remove the oil filer cap to get the to the MAF, but I'm leaving the MAF sensor disconnected and seeing if that resolves it.

I'm going to try cleaning the MAF sensor insert first, looks like its just held in by a couple of security torx screws.
 
Thanks.
90% sure its the MAF sensor - I reconnected everything and went on the school run this afternoon - fault reoccurred - I had put the tools in the boot just in case, popped the bonnet & pulled the MAF connector and hey-presto! Engine revs again. I suppose I did also remove the oil filer cap to get the to the MAF, but I'm leaving the MAF sensor disconnected and seeing if that resolves it.

I'm going to try cleaning the MAF sensor insert first, looks like its just held in by a couple of security torx screws.
The MAF definitely cause those issues (limp mode), the pierburg maf I fitted at the same time as my synergy 2a box back in 2018, failed a few weeks back, so I plugged my Foxwell NT530 in & it gave the problem straight away so I fitted the original Bosch one that I kept & it was back to normal. Have you plugged it in to a decent scanner ?
 

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