Volvo ME9 - MAF Flow Too High

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h2esk

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	Volvo ME9 - MAF Flow Too High « on: February 23, 2023, 06:48:16 AM »

I'm working on a Volvo with my friend, forged 2.5T, hybrid turbo, yadda yadda yadda.

We switched to Focus RS MAF, as we were approaching the limit of stock MAF sensor.
After we replaced MAF, we upped the load request, but something strange started to happen, the throttle would start to close when the mass air flow was crossing approximately 950kg/h threshold, also the lambda request was going straight to 0,7. It is not overboost related.
Upping thresholds in KFMLDMX, MLDHFMKO doesn't do anything.

The DTC read by Vida states ECM-122C MAF Flow Too High, the DTC corresponds to HFME fault class, so it would mean an electrical error (?)

Comparing the Focus RS file and our Volvo file I can see that electrical diagnosis of the HFM and also the flow diagnosis is a little different. But I'm stuck right now with no idea what to do next.

In the link you can find both Focus RS software with A2L and Volvo bin with .kp file for WinOLS, also included is Volvo .idb for Ida PRO with some memory addresses labeled (probably contains errors).

If someone could at least guide me in the direction what to look for I would be really grateful.

Thanks in advance!

LINK: https://drive.google.com/file/d/1pQjRK6flCbhE07feMGmHNHISQukLP99r/view?usp=share_link


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prometey1982

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	Re: Volvo ME9 - MAF Flow Too High « Reply #1 on: February 23, 2023, 07:03:48 AM »

You have to modify KFMLDMX map. And maybe MLmax value.


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h2esk

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	Re: Volvo ME9 - MAF Flow Too High « Reply #2 on: February 23, 2023, 07:06:45 AM »

KFMLDMX was modified, MLMAX appears to not be present in this software. But I can be blind.


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prometey1982

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	Re: Volvo ME9 - MAF Flow Too High « Reply #3 on: February 23, 2023, 07:29:11 AM »

Function at addr 0xFDD24 returns diag data from get param by index command. It's very useful function for reverse engineering. It's Volvo specific command. I didn't find anything equal in Audi's software. Maybe Ford's has such function.


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prometey1982

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	Re: Volvo ME9 - MAF Flow Too High « Reply #4 on: February 28, 2023, 07:14:18 AM »

There is more checks on HFM inside Volvo ME9. Check MLDHFMKO value.


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h2esk

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	Re: Volvo ME9 - MAF Flow Too High « Reply #5 on: February 28, 2023, 07:17:01 AM »

Also changed those values, still the issue persist.


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prometey1982

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	Re: Volvo ME9 - MAF Flow Too High « Reply #6 on: February 28, 2023, 07:25:12 AM »

And this value UHFMMX at addr 0x1C3EA6?
Threshold for uhfm max failure during 1ms test.
Value from Volvo ME9 binary is 4,9023


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Cheekano

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	Re: Volvo ME9 - MAF Flow Too High « Reply #7 on: February 28, 2023, 03:27:32 PM »

I can't open your kp file due to being a newer version so I can't see what's done but when I did my RS4 MAF, I did the following:
Translated over the MSHFMU and set KFKHFM all to 1. (All fueling is done via FKKVS. That is the same as with the Focus RS from factory, even the RS4.)
You also need to set CDEHFM to 0 to disable diagnosis.
Of course KFMLDMX, MLDHFMKO, MLDHFMKU and KFMLDMN have to be adjusted.


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prj

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	Re: Volvo ME9 - MAF Flow Too High « Reply #8 on: March 01, 2023, 01:48:42 AM »

Quote from: Cheekano on February 28, 2023, 03:27:32 PM

You also need to set CDEHFM to 0 to disable diagnosis.

No, you don't. You need to adjust the thresholds correctly.
Disabling diagnosis means if your MAF dies you are stranded, pretty dumb.


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h2esk

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	Re: Volvo ME9 - MAF Flow Too High « Reply #9 on: March 01, 2023, 02:28:24 AM »

Quote from: prometey1982 on February 28, 2023, 07:25:12 AM

And this value UHFMMX at addr 0x1C3EA6?
Threshold for uhfm max failure during 1ms test.
Value from Volvo ME9 binary is 4,9023

I was disassembling the Volvo file and comparing it with Focus RS with memory locations loaded from A2L(thanks for the script prj). Haven't found UHFMMX in my file, or at least I can't see it. Also we are not approaching 4,9v with our current flow and MAF housing with Focus RS insert in. But I will look into it some more. Thanks for all of your help.

Quote from: Cheekano on February 28, 2023, 03:27:32 PM

I did everything that you mentioned apart from setting CDEHFM to 0.


« Last Edit: March 01, 2023, 02:40:49 AM by h2esk »	Logged

prj

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	Re: Volvo ME9 - MAF Flow Too High « Reply #10 on: March 01, 2023, 04:01:01 AM »

Quote from: h2esk on March 01, 2023, 02:28:24 AM

I did everything that you mentioned apart from setting CDEHFM to 0.

And if you do that, then if your MAF fails or a hose pops off you will most likely be stuck with a non-startable car in the middle of nowhere...

Can you share stock and currently modified file?
Stock is in first post, but show also the mod, maybe some simple mistake.


« Last Edit: March 01, 2023, 04:06:18 AM by prj »	Logged

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h2esk

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	Re: Volvo ME9 - MAF Flow Too High « Reply #11 on: March 01, 2023, 04:06:59 AM »

Quote from: prj on March 01, 2023, 04:01:01 AM

And if you do that, then if your MAF fails or a hose pops off you will most likely be stuck with a non-startable car in the middle of nowhere...

I'm well aware of that and I want to do it properly

Quote from: prometey1982 on February 28, 2023, 07:25:12 AM

And this value UHFMMX at addr 0x1C3EA6?
Threshold for uhfm max failure during 1ms test.
Value from Volvo ME9 binary is 4,9023

See the screenshot attached, I can't find UHFMMX in my file. It is present in Focus RS binary.


« Last Edit: March 01, 2023, 05:11:17 AM by h2esk »	Logged

prj

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	Re: Volvo ME9 - MAF Flow Too High « Reply #12 on: March 01, 2023, 04:15:25 AM »

In your file the GGHFM module does not have UHFMMX and UHFMMN.
But post modified file.


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h2esk

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	Re: Volvo ME9 - MAF Flow Too High « Reply #13 on: March 01, 2023, 05:10:22 AM »

Quote from: prj on March 01, 2023, 04:15:25 AM

In your file the GGHFM module does not have UHFMMX and UHFMMN.
But post modified file.

I have posted before you edited your post. Here is the modified file.


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prj

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	Re: Volvo ME9 - MAF Flow Too High « Reply #14 on: March 01, 2023, 11:01:10 AM »

Quote from: h2esk on March 01, 2023, 05:10:22 AM

I have posted before you edited your post. Here is the modified file.

I think you misdefined a bunch of shit and then went over it with a sledgehammer...
I fixed the MAF part, I didn't look at anything else.


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