Fault code P006A-00

[v8sruleok]

Hi,

I have multiple codes coming up on my 2011 SDV6. I have had the car into a workshop lately, they pressure smoke tested the intake and found no leaks, but didn't have time to fix the problem as I needed the vehicle for Easter towing duties.

I have just been reading some info on one of the Jag forums, and am pasting this quote,

"fault code P006A-00 ....... which refers to 'Mass Airflow Correlation. This fault code means that 1 bank of the engine has a different air pressure from the other bank".

I raise this because in RTFM I can find no reference to said fault, only faults P006A-21, and P006A-22.

The other faults I'm getting P0235-94, turbo boost 'A' circuit component failure, and P1247-00, turbo boost low.

Can you guys please confirm my info from Jag Forum is correct?

Do you think that I could still be looking at a cracked manifold?

I have visibly checked both manifolds and found no cracks in the usual places, removed the intercooler hoses and checked for leaks/splits, removed the shut off valve and checked for free movement of the butterfly and actuator, and inspected as many vacuum lines as reasonably accessible to do. I have not yet visibly checked any of the turbos, or the intercooler itself.

Running out of ideas now so any help much appreciated.

Thank you.

[justinc]

Check your MAF live values. I still reckon there is a manifold leak. Can you see ANY spits of soot or black specs on the underside of the acoustic cover??

[v8sruleok]

Tried to get some live values but every time we tried the vehicle would drop into "Restricted". What sort of numbers should I be expecting to see from the MAFs please? I will give that a check on my next test drive. Haven't had the cover on for months but it looks clean on the foam underneath. There is a tiny amt of oil mist on the 2nd injector pipe clamping nut LHS (it's adjacent to the breather tube which has a split boot which I have taped and cable tied tight for now). Thanks for yr info.

[DiscoJeffster]

Place white paper under the cover. Place it around the throttle body, intake manifolds etc. Go for a spirited drive. Check the paper for soot. That can help and is easier than a smoke test.
P006a is a correlation error - the
MAF has seen x amount of air which (without leaks) equals so much boost reported on the MAP sensor. When there is a leak the MAP reads lower than the corresponding MAF level. P006a reported. I’m an expert as I’ve had both manifolds and a throttle body split to cause the failure every god damn holiday lol

[v8sruleok]

DiscoJeffster, I know about yr issues, been reading about them in the quest to solve mine. A couple of weeks ago I put a clean white T-shirt across both manifolds and went for a drive and it came back as clean as it went out.....but maybe my driving wasn't spirited enough, I'll give it another go.

The relationship between MAF and MAP is something I need to work on. I did squirt them with Maf aerosol and swapped around a few months back, but I might just swap them back and see if it makes a difference.

I see that you are in my neck of the woods, thanks for yr reply.

[DiscoJeffster]

Apologies as I didn’t see the other two faults in your original post. Those are not similar in any way to my previous issues which leads me to think the 006a is not the primary issue.
Looking at other posts the compressor shut off valve gets a mention. Search the P0235-94 via google for a few posts on it.

[Eric SDV6SE]

I'll have to check my records at home, but that code and your cars symptoms sound like the air control valve may be sticking. This valve controls when the secondary turbocharger is activated and it works on the MAF sensor values.

Speaking from experience, when they stick it causes all sorts of issues. Easy to replace, just not cheap (about $1200)

[v8sruleok]

Thanks Eric,

I did some research last night relating to P0235-94 and the shut off valve looks a likely candidate.

Mine still has the original actuating arm assy but I can operate it manually from underneath with no binding in the mechanism apparant.

I removed the valve about a month ago and did a visual inspection of the butterfly and found nothing out of order, the whole thing was very clean inside and out and only a very small amt of oil came out of the lower hose assy at removal.

I maybe need to manually apply a vacuum to the diaphram module and see if the lever opens the valve.

Do you think that the error code could be triggered by the valve not opening (or closing) at the right time?

Cheers.

[Eric SDV6SE]

Definitely. There's also an air control solenoid that controls the variable vane primary turbocharger actuation. When that fails, it also throws up MAF error codes.

[LRD414]

..... I did some research last night relating to P0235-94 and the shut off valve looks a likely candidate.

Mine still has the original actuating arm assy but I can operate it manually from underneath with no binding in the mechanism apparant.

I maybe need to manually apply a vacuum to the diaphram module and see if the lever opens the valve...
In your other thread about a month ago there was suspicion re vacuum operation. Have you chased that through? Including the solenoid that controls the vacuum actuation? It is known to fail and is cheap to replace to eliminate as a cause. I carry a spare on remote trips for that reason.

Scott

[v8sruleok]

In your other thread about a month ago there was suspicion re vacuum operation. Have you chased that through? Including the solenoid that controls the vacuum actuation? It is known to fail and is cheap to replace to eliminate as a cause. I carry a spare on remote trips for that reason.

Scott

Hi Scott,

I am battling to trace potential vacuum leaks, if the vacuum lines are visible and accessible I have checked them, but sooner or later they become difficult to follow. Up until just now I have not inspected the vacuum actuator (rhs inner wall of eng bay), but I have just removed it. Looks okay to me, i put air into one of the side hoses and it comes out of the bottom hose, do I need to test the operation of the solenoid valve?

Thanks.

[v8sruleok]

Definitely. There's also an air control solenoid that controls the variable vane primary turbocharger actuation. When that fails, it also throws up MAF error codes.

Hi Eric,
Where is this located pls, could it be the one I have just removed in response to LRD414's query? Its first port of call heading south is the secondary but I think that the hose keeps going to the primary maybe.

Thanks.

[Eric SDV6SE]

One and the same that Scott refers to.

[v8sruleok]

I did some more testing today raising more questions than providing answers.

Wanted to know if I could get the TSOV to operate so I got the missus to rev the motor to 3K, noticed there was no movement of the actuator arm and subsequently no vacuum in the line either. Was wondering how many Rpm's I need to make this work. I have just asked Ferret about this in a previous post of his and hopefully will get a reply in due course.

The other thing, after re-connecting the turbo vacuum solenoid from my previous post took the car out for a quick spin. The turbo boost low came up as usual about 4 times in quick succession and then settled for a while, so I was able to boot it and it seemed to perform nicely. Got home and I was tinkering again and then it dawned on me that I hadn't reconnected the hose at the T piece into the secondary turbo. So hooked that back in, went for another spin, and there was no noticeable difference between the two test runs. So that got me thinking a bit....!

The TSOV or the solenoid that directs the vacuum to it is now my No.1 line of enquiry. I'm thinking of buying a vacuum pump and gauge tomorrow.

Cheers.

[DiscoJeffster]

I’m not sure with no load on the engine whether the actuator will move when revved at 3000rpm stationary

[v8sruleok]

I’m not sure with no load on the engine whether the actuator will move when revved at 3000rpm stationary

Yes, I agree....it's a worthy possibility. I could test the theory by doing two test drives, one with vac line attached, one with vac line removed and blocked off, and compare the results.

Thank you.

[LRD414]

I have seen my TSOV actuator move when revving the engine parked on the driveway. I don’t recall the rpm.

Scott

[v8sruleok]

Today I did some live data on my IID. I selected my 8 options, 2 of which were compressor shut off valve and compressor recirculation valve. Both shown to operate under upper rpm loads on the road.

That appears to be another one I can cross off my list. I did get some MAF and MAF values too, so I'll go looking in that direction to make sure that they correspond to normal values.

Cheers all.

[justinc]

Today I did some live data on my IID. I selected my 8 options, 2 of which were compressor shut off valve and compressor recirculation valve. Both shown to operate under upper rpm loads on the road.

That appears to be another one I can cross off my list. I did get some MAF and MAF values too, so I'll go looking in that direction to make sure that they correspond to normal values.

Cheers all.

What kg/hr were you seeing?

[mtthsk]

What kg/hr were you seeing?

Hi,
sorry to get this old thread back, but what should normal readings look like?

I do get 0.3 to ~1.2 g/s from the one (secondary) MAF and anywhere between 40 g/s and 140 g/s when driving normally. Above 2500 rpms the secondary MAF sensor shows a higher reading, while the first MAF sensors flow rate declines.

I suppose that is the way it should work, so can i tick the MAF sensors of my list of possible fault sources for my reduced engine power problems?

Cheers,
Matt

[vpnong]

First thing I have to say thank you all for posting lots of ideas, brainstorming ideas, engineering ideas to solve many complex technical cases from Discovery 3 and 4. No textbooks even from LR gurus who designed Disco 4.

My Disco 4 is 2011 #260000km, special edition of black and white in contrast in and outsides. Amazingly, this version is very much different from Disco 3 with diesel economical (8l/100 Hw), quiet if cruise driving, good insulation for snowy trips when sleeping in car, ZF gearbox for this model is very smooth responsive, off road is intelligent no problem if using low profile tyres... Many reasons why I never think of selling it. I love it like a member of my family.

However, it is getting old by days and become sick very often. I always look after it with tune up and services with my schedules even very expensive ways. I love mechanics both modern and conventional; To fix simple errors with listening, noticing strange noises, syndromes and conclusions of main sources to the problems those I learn/apply from my IT.

I do not know why AULRO did not allow me to express my ideas just until now. I figured out better approach to alter turbo oil pipe because bad design from LR, I did replace manifolds myself because dealer's quote was too high (> AUS$ 10000 and plus replacing timing belt $2500) I did not replace oil cooling housing ($600 for part and $400 labour) but I did just a set of seals ($12 China made) and importantly I found out reasons seals were collapsed.
I am proud of fixing error "Turbo shut off vale open" while dealers insisted turbo faulty and this was Restricted Performance. I modified throttle body to prevent leaks from Y piece joint with its body. My alternator sudden died, I replace carbon brushes. All I did because I do not like amateur technicians to touch sensitive and clean parts with dirty hands and sometimes destroy my bolts and nuts with unnecessary extra torque.

A week before 18th JAN 2025, I thought I must give up the repair of P006-00 error with Restricted Performance. It cost me a week to find down the MAF sensor problem and it is not the MAP sensor even error description confirms MAP corelation.

I am still learning... I appreciate "Eric SDV6SE", "Graeme", "v8sruleok", "Scott"...with their analysis abilities and also experiences in many different fields.

I will record how to repair an error next time.