P0101-22 MAF Nissan Xtrail 1.6d

[Dynion Araf Uchaf]

Hello

I have the fault code P0101-22 which relates to a MAF sensor fault (air flow sensor information)

I have used my diag tool to see what values it is displaying

See below




As you can see it gives a value and that value does change as the throttle is opened.

However the absolute throttle position is stuck at 89.2%.

I replaced the MAF and got the following results




This time the new MaF appears to be set at 0 and the absolute throttle position remains at 89.2%.

With the original Maf I get an MIL on first time I get to 3k rpm but I the engine pulls cleanly all the way to the Rev limit. With the new MaF I do not get an MIL but there is noticeable hesitation at 3k rpm

I have some historic data from the car and that shows that the absolute throttle position is variable as the throttle is moved.





So is the problem the Maf or the TB? I think the latter even though the code is for the Maf.

So I have already changed the Maf but this still gives me some faults.

Should I do a throttle relearn? Or even replace the throttle?

Is there anyone who can give me some pointers

[E-bmw]

Looks to me like perhaps your original MAF was working but the throttle position is not being reported correctly.

Engine codes that report MAF issues are actually rarely the MAF at fault, but normally something that makes the MAF output implausible.

Fit your original MAF, check live data is reading it as a live reading rest any codes & take it for a drive, see what happens.

Don't know about Nissan specifically but MANY manufacturers cars DO NOT LIKE cheap copy engine sensors, don't know if this is relevant in your case, just sayin'.

[Dynion Araf Uchaf]

Yeah I ve re fitted the old one, and it does work albeit pops the mil on.

I am erring towards the tps. But may have to take it to a dealer to sort , hoping it’s just a reset required.

[E-bmw]

Dynion Araf Uchaf said:

Yeah I ve re fitted the old one, and it does work albeit pops the mil on.

I am erring towards the tps. But may have to take it to a dealer to sort , hoping it’s just a reset required.

Unfortunately unless there is a VERY well documented reset/re-learn procedure in their technical bulletins, they will just go straight for a swap.

[Dynion Araf Uchaf]

In that case then what’s stopping me fitting a used one, or possibly a new one myself?

I am only looking at the dealer option as I thought there might be some jiggery pokery required.

[LordLoveLength]

Worth going into OBDII mode and checking values for live data there - you may be seeing substitute values that the ecu defaults to due to out of range sensor readings.
OBDII will always show sensor readings. This may point your diagnosis in a different direction.

[Belle427]

If its a Diesel there is no throttle body as such is there?
Its probably a shut down flap which will display a large percentage as its alway open until engine off.
Just a guess really, as someone else said Maf codes can be related to other issues such as Vacuum leaks stuck egr etc.

[Dynion Araf Uchaf]

LordLoveLength said:

Worth going into OBDII mode and checking values for live data there - you may be seeing substitute values that the ecu defaults to due to out of range sensor readings.
OBDII will always show sensor readings. This may point your diagnosis in a different direction.

Yes done that. Recorded the data on a drive, and it looks to me like the throttle position is in some kind of default.

The new MaF interestingly , is from China ( I thought I bought it from a reputable a British seller) I think it has been “engineered” to not put the mil on, but not actually fix anything. If you don’t have a diag machine you’d be happy just to see the light out, and then wonder why the car conks out 6 weeks later

[Dynion Araf Uchaf]

Belle427 said:

If its a Diesel there is no throttle body as such is there?
Its probably a shut down flap which will display a large percentage as its alway open until engine off.
Just a guess really, as someone else said Maf codes can be related to other issues such as Vacuum leaks stuck egr etc.

Using the live data I can see that as the engine is switched off the flap does it’s recycling thing and it shows as different percentages on the data.

I’m not sure whether I’m get a new genuine TB or a secondhand complete unit.

Not a stuck egr, I’ve had that out and cleaned it a few weeks ago. I’ve checked the inlet tubes for leaks- none found.

[Belle427]

Have things like intercooler/pipework been checked for leaks?

[Dynion Araf Uchaf]

Yes checked. All pipes downstream of the Maf (there is only one) are in good condition (to my eyes)

[LivLL]

Sounds like original MAF is good and you have an air leak somewhere. Do you have a smoke tester?

[Belle427]

The replacement Maf reporting at zero would be a concern, seems to suggest disturbing the wiring has done something?
Was it a genuine Maf?

[Dynion Araf Uchaf]

LivLL said:

Sounds like original MAF is good and you have an air leak somewhere. Do you have a smoke tester?

Correct me if I am wrong, but any air flowing to the Maf whether through a leak upstream won’t impact the Maf Reading/ecu values. However any additional air flowing from behind the Maf, could impact the ecu values.

The Maf is sat direct behind the air box - downstream. And there is only one rubber pipe to the turbo from the Maf.

I’ve focused on the pipe down stream and there is no leak, upstream there could be a leak but only because it’s plastic pipes interconnecting and I don’t believe they’ll be 100% air tight even from the factory.

In any case I have checked them and they seem fine

[Dynion Araf Uchaf]

Belle427 said:

The replacement Maf reporting at zero would be a concern, seems to suggest disturbing the wiring has done something?
Was it a genuine Maf?

See earlier post

[LivLL]

Anywhere unmetered air can get in will mean MAF reading doesn’t match actual and you’ll have similar symptoms to yours.

Smoke machine will find leaks you’ll never find by just inspecting.

It could be many things but that’s one of the basic checks.

Was there anything leading up to this code appearing in terms of replacement parts, servicing or such?

Edit to add - what’s the MAF reading at idle.?

Edited by LivLL on Sunday 2nd February 09:56

[Dynion Araf Uchaf]

LivLL said:

Anywhere unmetered air can get in will mean MAF reading doesn’t match actual and you’ll have similar symptoms to yours.

Smoke machine will find leaks you’ll never find by just inspecting.

It could be many things but that’s one of the basic checks.

Was there anything leading up to this code appearing in terms of replacement parts, servicing or such?

Edit to add - what’s the MAF reading at idle.?

Edited by LivLL on Sunday 2nd February 09:56

Prior work was cleaning an IAT in the throttle housing.

Maf reads about 7 at idle

[Belle427]

May be worth seeing if it graphs ok such as the link below, not sure if its going to be the same on a diesel engine.
https://www.alldata.com/sites/default/files/file-a...

[E-bmw]

Dynion Araf Uchaf said:

Prior work was cleaning an IAT in the throttle housing.

In that case take it out & check the o-ring is sited correctly and it is tightened up as it should be.

[LivLL]

Dynion Araf Uchaf said:

Prior work was cleaning an IAT in the throttle housing.

Maf reads about 7 at idle

7 seems high, I don't know that engine but 1-2 is more "normal". Any info on the Nissan forums that might give a value?

Give or take a bit it's generally 1g/s per litre of engine size as a rule of thumb.

Edited by LivLL on Sunday 2nd February 13:28