U0401 & P0299 fault combination Transit Mk8

[micmacdevon]

Hi all.....any help/comments gratefully welcome !

2015 Transit 125 T350 Mk8 2.2 RWD H3L2 Camper conversion.

Having issues with my 2.2 RWD 2015 Mk8 camper. If anyone has same ( seeing some on here ) please let me know and I will share any info I find also.

I am in process of researching this extensively (you might say obsessively !) and now have mechanic involved. Here's the full story so far......! I shall start a fresh thread as this combination of codes seems common on the Mk8 !

Bought camper conversion from chap who had spent small fortune replacing turbo (for overboost issue...! could have just cleaned it out with additive so I'm told my the mechanic), egr, glow plugs and more. Scanned ECU with diagnostics and no CMDTCs found and 3500mile covered since last dtc's cleared which tally with the turbo replacement. Test drove lovely !

Drove approx 350miles no issues after purchase.

Had particularly cold snap ,rain and ice. The early MK8s suffer from water ingress into engine bay via both seal on lower edge of windscreen AND the fact the early only did not have plastic diverter gully on passenger side, so that water from screen and side channel pours right in onto your ECU and connectors !!!! and pools in heat shield below wiper arms dripping right onto HT lead then down on to TURBO ACTUATOR (key to all this we now think). I have done the mod to resolve this (will do a YT vid later - but Ford really should have done a recall), dried all out and checked ECU connectors for corrosion ( none seen) and cleaned with specialist electrical contact cleaner etc. The ECU itself is pretty well sealed so hopefully that's not the issue but......!!

Van throws up following codes driving up moderate country lane hill approx 25mph :
P0299:00-24 turbo underboost logged in CMDTC (Topdon scan found this later) but no warning lights etc at time of detection by ECU
Then U0401:68-48 ( showing on the ABS system !?) together with "ENGINE SERVICE NOW and the traction control light on about 120 mile later ( found this via freeze frame data)
Van in limp mode.
Cycled ignition off/on and it clears.....turbo boost back......no issues for 5 ish miles.......then same again.
Both codes show on scanner. Then no problems fro 10/20 miles or so after ignition cycle off/on (obviously its holding codes in CMDTS's)

Checked all turbo hoses etc (one was newish other older but ok) ......found the throttle valve ( its an anti knock valve really on a diesel) had fair bit of carbon build up so replace (bugger of a job to get to from under)

Replaced both batteries ( Starter was almost dead and aux not much better - but they were original ford from 2015 !!)(Bare in mind the Mk8 twin batteries are the other way around to the Mk7 ie Mk8 front is isolated/dedicated starter and rear is auxiliary - I believe the Mk7 is the other way around from many comments in forum)

DPF pressure bit high but not off the chart so did MANOL foam clean just to be sure of any DPF issues.

Cleared codes.....test drive and the issue seemed to be gone.......or so I thought.....! For about 20/30 miles all good. Then "engine service now"/traction light returns......

So.......took closer look and turbo actuator......its well hidden behind and below alternator so had to go from up under van near front end of exhaust with light and......both ends of the actuator rod rusted and potentially seized (or restricted - see pics) also noted the actuator (recon) code is G74 (these are for the 3.2 ltr transit and ranger engine and I'm told are turbo specific ! Apparently should be a G59 ?

So blasted the actuator rod ends with wd40 from below and above (difficult)

Mechanic comes and he's already saying "it's probably the actuator as they have this issue....." Bare in mind its an electronic actuator....so if fails or inhibited may well throw and electrical fault (U0401- just why this would be on the ABS system is another question) and a turbo under boost code.

Given that the rod ends of the actuator had been soaked in wd40 the previous day, the mechanic said lets test the actuator with the scanner ( he has a fancy one that can do that instruction to the actuator to move. Well it did, but only in the mid range range, nothing up to approx 20 and nothing over 80 (where it sits at idle apparently ?). But its a g74 so that may be ok......or......some of the teeth in the actuator gearing / electrical contacts are dodgy ( after market ones don't have a good feedback thingy apparently and this could be an issue) or water damaged possibly ?

Cleared all codes.......Took for test drive and both faults return........

Anyway.....that's where it is at the moment.......we now have to decide whether we just remove alternator to clean up actuator rod ends as a possible cause or get up underneath, drop exhaust front end and replace actuator with...well its anyone's guess as to g74 or g59 which I believe it should be ??? but may not be specific for that newish turbo previous owner had fitted ?

Ford will not sell actuator on its own, only turbo with actuator.
There are some mechanics on here that say they will not replace with after market actuators and only new ford full turbo/actuator as too many come back with issues.......tell me about it !

Something at the back of my mind is telling me its possibly another electrical issue altogether......dpf block / vapourizer fault could well throw up both these codes just as easy..........but will go down this route for now as seems most obvious and see where it leads.

Will update as I go so hopefully will help me (if someone knows the solution) and others (if I get it fixed ) with same issues.

Cheers

(not sure how to post the images here so will try and add later)

[metalworker0]

You could do with spray grease on the actuator not wd40

The underboost is often the EGR valve stuck open,
AND - I dont know why but -- reports here that EGR fault sets ABS/ traction control fault U0401

.So EGR - . perhaps carboned up ,,,needs dismantling and clean ?

Or holes in the boost pipe
i know the 2.2 custom has a problem with the boost pipe rubbing on a bolt that causes a hole in it, but that is a fwd...a very small chance may be the same for mk8.

all the best.mark

[micmacdevon]

You could do with spray grease on the actuator not wd40

The underboost is often the EGR valve stuck open,
AND - I dont know why but -- reports here that EGR fault sets ABS/ traction control fault U0401

.So EGR - . perhaps carboned up ,,,needs dismantling and clean ?

Or holes in the boost pipe
i know the 2.2 custom has a problem with the boost pipe rubbing on a bolt that causes a hole in it, but that is a fwd...a very small chance may be the same for mk8.

all the best.mark

Thanks Mark !

Yes was thinking grease on those but just wanted to free them up to start.

It's had a recent new egr and boost pipes checked and ok ( yes the rubber coated support one sits/rubs on is an issue I have seen, but mine ok and I have reinforced.

Cheers for reply !

[micmacdevon]

Should add the following......as 2 other ADDITIONAL fault codes of P1708 (Clutch switch circuit) and C0051 (steering wheel position sensor) showed up in early scans diagnostics but only returned once in subsequent scans / test drives.....but get cleared with DTC clear for test drive (so possibly intermittent fault on clutch suppression switch ?

If the (suppression) clutch switch is faulty, I'm thinking it will throw the U0401 electrical fault code and it will limit revs to 3000rpm if ECU thinks clutch is depressed.......start to climb a hill and that could throw a turbo under boost as you put your foot down on the accelerator AND trigger limp mode and warning (Service now / Traction light).

Thinking back to first time it threw a fault up on dash (engine service now / traction control light) I pulled over and van would not rev past 3000rmp ( the clutch suppression limit) NOT 2000-2500 RPM which I think would be the rev limit for limp mode ? It certainly had more, if somewhat reduced, power up the hill unlike a typical limp mode scenario !

The ECU has logged 4025 TCS (TRACTION CONTROL SYSTEM) Events !!!!!!!

There are two clutch switches......lower (white one with relatively easy access) is the starter suppression switch and higher (black one) is clutch pedal position sensor.....nightmare to get to on Mk8.

Some of the Freeze frame data (FFD) from initial fault trigger does state " Clutch pedal beyond top of travel switch"

The clutch pedal itself has clearly been greased up before and does sometime fail to return fully........

May sound silly......but a faulty clutch suppression switch in theory could cause the 2 main codes (U0401 & P0299) and put into limp mode !?

I have both switches so think will do this first as easiest route to possible issue.....

[metalworker0]

i don't know what software you are using

if using forscan it would allow actuator test ..egr test etc .. youd then be able to see them move

we still don't know if waste gate is stuck open ..not sure how clutch fault is related to antiilock or underboost

are these a mumbo jumbo that the vans brains heap together ?

Note: when there are lots of faults appearing and all unrelated ..can often be down to a bad battery / bad earths etc

all the best.mark

[micmacdevon]

i don't know what software you are using

if using forscan it would allow actuator test ..egr test etc .. youd then be able to see them move

we still don't know if waste gate is stuck open ..not sure how clutch fault is related to antiilock or underboost

are these a mumbo jumbo that the vans brains heap together ?

Note: when there are lots of faults appearing and all unrelated ..can often be down to a bad battery / bad earths etc

all the best.mark

Using Thinkcar 689BT Diagnostics and did actuator test. Only moving in the 20-80% range ( but its a G74 actuator and believe should be a G59 ?) so this might be a red hearing.

"Clutching at straws" re the clutch switch......but in theory if its faulty / shorting (as per the occasional P1708 clutch switch circuit error it "could" throw the U0401 and limit revs leading to underboost......but thats just an idea, so will change both clutch switches to eliminate from the possible causes. Seized actuator rods seems most obvious atm. Will Update if solution found.

Cheers.

[metalworker0]

moving into realms ive never looked into or studied now

you say actuator motorised

i googled G74 actuator

if so does motor and gearbox look like this ... note opened up so you can see inside of it ... motor , pinion, worm drive ... think the green disc is an encoder --- so a bit sophisticated
https://www.turbosacer.com/wp-content/u ... 30-new.jpg

if so ..what's to stop it stripping gears or damaging plastic parts within, if the rod seized up.

also the flap valve / butterfly valve could seize up inside the manifold .

all i say ..if above is what you have anything possible as far as damage is concerned

all the best.mark

[metalworker0]

just saying when things get as complicated as this .. if you were to take this to an american mech in a garage -- they use a much more systematic approach to this rather than..what they call "throwing the parts cannon at it."

Some have a computer that runs a application called "Alldata"

First it lets you put make and model in, then you put the codes into the computer ..it then brings up hundreds of solutions submitted by real people ..and the top ones are listed first.. from its database.

When trouble shooting there are flow charts to easily take you to problem area... does it do this .. no ..move onto number 20 etc

The mk8 manual does have some of the workings of this ... big but ..the move onto number 20 does not work because its not indexed... because its a copy rather than the real thing ! ..so you have to manually find number 20

NOTE : don't show in browser --- press download
https://drive.google.com/file/d/1Nw1OtK ... view?pli=1

NOTE: these manuals are awful to search through ..and it may take you sometime to search through 3000 plus pages

all the best.mark

[micmacdevon]

moving into realms ive never looked into or studied now

you say actuator motorised

i googled G74 actuator

if so does motor and gearbox look like this ... note opened up so you can see inside of it ... motor , pinion, worm drive ... think the green disc is an encoder --- so a bit sophisticated
https://www.turbosacer.com/wp-content/u ... 30-new.jpg

if so ..what's to stop it stripping gears or damaging plastic parts within, if the rod seized up.

also the flap valve / butterfly valve could seize up inside the manifold .

all i say ..if above is what you have anything possible as far as damage is concerned

all the best.mark

Thanks Mark will have a look, but yes its electronic actuator and will be as you describe.....and yes.....a seized rod could potentially cause cogs and electrics to fail......hence not moving though full range......but issue is that its a G74 ( for the 3.2 ltr engine) but given working fine before issues its hard to know without taking off and opening......which will be on the cards if changing the actuator rod does not resolve.

Cheers

[micmacdevon]

just saying when things get as complicated as this .. if you were to take this to an american mech in a garage -- they use a much more systematic approach to this rather than..what they call "throwing the parts cannon at it."

Some have a computer that runs a application called "Alldata"

First it lets you put make and model in, then you put the codes into the computer ..it then brings up hundreds of solutions submitted by real people ..and the top ones are listed first.. from its database.

When trouble shooting there are flow charts to easily take you to problem area... does it do this .. no ..move onto number 20 etc

The mk8 manual does have some of the workings of this ... big but ..the move onto number 20 does not work because its not indexed... because its a copy rather than the real thing ! ..so you have to manually find number 20

NOTE : don't show in browser --- press download
https://drive.google.com/file/d/1Nw1OtK ... view?pli=1

NOTE: these manuals are awful to search through ..and it may take you sometime to search through 3000 plus pages

all the best.mark

Typically in UK garages.....they just recomend the most expensive fix ! As the previous owner has spent small fortune with new turbo, egr etc.
Water ingress issues probably the key here and may well be a simple and most obvious fix. Will re check the most obvious things this week......

cheers

[metalworker0]

This place list it as 2,2

https://www.ecutesting.com/product-cata ... tua6nwg74/

and this place

https://uk.fridayparts.com/turbo-actuat ... uRJxPbsJD_

a search here sees g74 only mentioned in this post

loads of cross referencing on ebay listing g74 the same as g88 and g59 ..but you cant rely on ebay.
as regards finding more info ..
"catcar info " is driving me nuts with "503 Service Temporarily Unavailable" lengthening my searches on the site by sometimes 20 mins or more ..

all the best.mark

[micmacdevon]

This place list it as 2,2

https://www.ecutesting.com/product-cata ... tua6nwg74/

and this place

https://uk.fridayparts.com/turbo-actuat ... uRJxPbsJD_

a search here sees g74 only mentioned in this post

loads of cross referencing on ebay listing g74 the same as g88 and g59 ..but you cant rely on ebay.
as regards finding more info ..
"catcar info " is driving me nuts with "503 Service Temporarily Unavailable" lengthening my searches on the site by sometimes 20 mins or more ..

all the best.mark

Yeah I'm getting it down to g59/g74 as is on there now and g88. Why ford can't just tell you what it is I can't understand. Catcar don't list it as a separate item. Whole turbo only inc actuator. Might have to put out a seperate request on here to see if anyone know the actual Hella actuator used by ford.......

Cheers !

[Mranoncustom]

Hi, might be a silly question but im just wondering if you have checked if there is water ingress into your air filter? I'm assuming this rwd has the bypass filter on the top then the air filter inside the housing.

Pretty common to get water into if the diverter on the scuttle panel is either blocked up or not there.

[micmacdevon]

Hi, might be a silly question but im just wondering if you have checked if there is water ingress into your air filter? I'm assuming this rwd has the bypass filter on the top then the air filter inside the housing.

Pretty common to get water into if the diverter on the scuttle panel is either blocked up or not there.

Hi

Yes have checked this. All seems fine but given the water ingress previously ( now all sorted with mods ) it is a possible factor. Turbo inlet looking spotless so hopefully thats a good sign this was not an issue.



But defo water ingress connected......shorted in actuator most probably as there was water dripping down in that area right behind alternator.....

Cheers for reply !

[Mranoncustom]

One other thing I would check before you go down the route of the actuator being the issue is checking the intercooler to throttle valve pipe. It's also common to rub on the cross member and will certainly cause an underboost dtc.

If all is well there then next I would back probe the actuator plug and check the turbo position sensor voltage is changing as the actuator moves. Sometimes the actuator can move too far out of range that the position sensor cannot read. (In the event that the actuator became stuck then freed off).

It is also possible like you say the internals are broken but I would attempt this first before spending money on a turbo or actuator

There is a way to bring them back in range so that the position sensor can read again. (If that is the issue)