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[webby23]

Hi all

Have an ongoing problem with the codes 0170 and 0173.

I know these are Fuel Trim malfunction on both banks, but wondered where to start with trying to remedy the fault??

Car runs perfectly, starts first time every time and shows good mpg figures.

I have a fault reader so all i have been doing is resetting every time the eml light comes on.

I have noticed it comes on religiously after 3 journeys, whether the journeys be 15 mins long or 200 miles long, and the car behaves perfectly before and after the eml light shows.

Any help gratefully received !!!

Cheers

Martyn

[ians]

... both banks, so something common.  MAF sensor maybe, although I think thats an unusual fail point :-/

[webby23]

ok thanks, is there anytthing else it could be?

[feeutfo]

ok thanks, is there anytthing else it could be?

Nothing else proven is far as i know. Albatross had a lengthy thread on this, cured by new maf. It is accepted on here that mafs rarely fail as such. For what ever reason the thinking is that the maf sometimes becomes less accurate i guess? Maybe its dirty? Cleaning tends to bugger it though.  Drive by wire cars seem to measure more accurately maybe? Certainly seem more affected.

Do you have the pre cat code?

[webby23]

No idea what the precat code is mate, i just get 0170 and 0173

Maybe i should try a new maf

[martbax]

Almost certainly the maf sensor. I had exactly the same problem and after several visits to VX agent I decided to sort it out myself. I bought a genuine Bosch replacement MAF off the internet (much cheaper then VX). Took about 20 minutes or less to fit - instant cure. The fault code only registers when you are in closed loop mode (i.e. engine warm) and it takes three occurrences of this code to trigger the eml. I can give you a detailed explanation of why the long term fuel is affected if you want but it takes a lot of typing.

[Proz]

Hi all

Have an ongoing problem with the codes 0170 and 0173.

I know these are Fuel Trim malfunction on both banks, but wondered where to start with trying to remedy the fault??

Car runs perfectly, starts first time every time and shows good mpg figures.

I have a fault reader so all i have been doing is resetting every time the eml light comes on.

I have noticed it comes on religiously after 3 journeys, whether the journeys be 15 mins long or 200 miles long, and the car behaves perfectly before and after the eml light shows.

Any help gratefully received !!!

Cheers

Martyn

Ive got the same problem and have a genuine maf on order .... i.ll let you know if it cures it  

[webby23]

Please do mate.

Sounds like it may be worth replacing the maf then

[Proz]

Please do mate.

Sounds like it may be worth replacing the maf then

Well im not so sure because on here they say they hardly ever fail but im at the end of my teather with this code so ive got to do something or sell it :-/ .... if this doesnt work then i'll change the O2 sensors but thats it after that  

[Kevin Wood]

I have seen this on a couple of the DBW V6s and it's been the MAF. I think the later MAFs are not as reliable as the earlier ones.

They seem to fail such that they lose sensitivity. If you look at the readings in the live data it looks OK, varies with throttle as you'd expect, but compare it with a "known good" one and you see straight away that it was reading low.

There are other possibilities which you should eliminate before shelling out on a MAF. Air leaks into the post-MAF area of the induction system, poor fuel delivery (blocked filter / low pressure / clogged injectors), etc.

Trying a MAF from a known good car is a good way to diagnose, or failing that compare the live data with that from a goos example with the same engine.

EDIT: Tried cleaning one MAF which had failed in this way to no avail whatsoever.

Kevin

[Proz]

In a previous post i put up some of the live data and asked if anyone with a 2.2 like mine could do a comparison but no one did  ( i think you looked at it and said it looked plausible ).... i found a genuine new Vx maf on ebay that was cheaper than TC so i decided to take the plunge and try it , hopefully it might be here today or tomorrow .... i have had a look for air leaks but as far as i can see it looks ok .
The car was serviced by Vx 5 months or so ago and had a new fuel filter but i dont have any way of checking the pressure that i know of  :-/

[Proz]

For your info i changed my airflow meter for Genuine Vx part and noticed a big difference in the car performance straight away ... seems to have found the power again ... and not had the 0170 code back yet ... fingers crossed though  

[webby23]

Brilliant mate thanks for getting back to us with that...........I think i will eliminate the MAF from the list by replacing it before anything else then

Thanks again and good luck with yours too

 

[Kevin Wood]

Excellent news.  

Kevin

[Proz]

Brilliant mate thanks for getting back to us with that...........I think i will eliminate the MAF from the list by replacing it before anything else then

Thanks again and good luck with yours too

 

I only hope it fixes your problem too .... but certainly mine has seen a big improvement in performance since fitting it