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Author Topic: Me 7.5 1.8T, "mad signal to low" DTC, but it doesen't go in safe mode  (Read 4395 times)
BlackT
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After the prj said in one tread about MAF on ME7, i start too look difrerent and noticed some things.
First ME7 512 kb ECUS that doesen't have ECM relay (like 4B0 906 018, 8N0906018AB...), they don't use MAF at all( I am not 100% clear about this) it calculates g/s acording to actual boost, and not real MAF reading
It was strange to me that TT have 130 g/s with k03s, same with my friends A4

And now similar thing on 1kb ECU
This night MAF on friend of mine car has failed... I disconnected it, and there is a "MAF to low" DTC, but it doesen't go in limp mode. It boost and runs really fine
I don't have eather any O2/WBO2 connected to ECU( I use external to monitor AFR)
Code:
Edit Log for 4B0906018DC_Tuned_v1.bin created by TunerPro.
**************************************************************************
12/18/2019 09:59:44  Scalar:    CWKONABG changed from 5.00  (0x05) to 0.00  (0x00).
12/18/2019 09:59:48  Scalar:    CDNWS changed from 2.00  (0x02) to 0.00  (0x00).
12/18/2019 10:00:32  Scalar:    KRKTE (Conversion of relative fuel mass (rk) to effective injector on time (te)) changed from 0.104784 ms/% (0x03B0) to 0.108780 ms/% (0x03D4).
12/18/2019 10:00:56  Scalar:    CWSLS (Configuration of Secondary Air System) ok changed from 1.00  (0x01) to 0.00  (0x00).
12/18/2019 10:01:08  Scalar:    CLALSH (P0138, P0137, P0140, P0136) ok changed from 3.00  (0x03) to 0.00  (0x00).
12/18/2019 10:01:13  Scalar:    CLAHSHE (P1105, P1117, P1118) ok changed from 3.00  (0x03) to 0.00  (0x00).
12/18/2019 10:01:19  Scalar:    CLAHSH (P1114) ok changed from 3.00  (0x03) to 0.00  (0x00).
12/18/2019 10:01:31  Scalar:    MSLBAS (Ini - Secondary air mass) ok changed from 25.20 kg/h (0x3F) to 0.00 kg/h (0x00).
12/18/2019 10:01:52  Table:     (KFMIOP) Optimal Engine Torque Map (Torque Calculations)  changed.
12/18/2019 10:02:11  Table:     KFLDHBN (maximum requested pressure ratio) OK/NO changed.
12/18/2019 10:02:57  Table:     KFLDRL (Map for linearization of boost pressure) ok changed.
12/18/2019 10:04:09  Table:     KFLBTS (Nominal Lambda for component protection) changed.
12/18/2019 10:05:42  Table:     ESKONF (Configuration of components power amplifiers  ) ok changed.
12/18/2019 10:05:49  Table:     ESKONF 2 (Configuration of components power amplifiers 2 ) ok changed.
12/18/2019 10:07:49  Table:     LDRXN ok changed.
12/18/2019 10:09:14  Table:     LAMFA AFR(Lambda - driver desired) ok changed.
12/18/2019 10:09:33  Table:     MSLUB (Secondary air mass of the battery voltage dependent) ok changed.
12/18/2019 10:11:09  Scalar:    EDLDRP changed from 100.00  (0x0A) to 400.00  (0x28).

In attachment is original,and modified file.
I am wondering how is that possible? Why ECU doesen't reduce load, go in limp mode or something?
« Last Edit: December 18, 2019, 09:58:53 PM by BlackT » Logged
RBPE
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« Reply #1 on: December 18, 2019, 03:58:43 PM »

GGHFM/GGDSAS/SY_EGFE bit sets etc, look into those and follow what they go into detail on
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prj
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« Reply #2 on: December 19, 2019, 02:26:24 AM »

After the prj said in one tread about MAF on ME7, i start too look difrerent and noticed some things.
First ME7 512 kb ECUS that doesen't have ECM relay (like 4B0 906 018, 8N0906018AB...), they don't use MAF at all( I am not 100% clear about this) it calculates g/s acording to actual boost, and not real MAF reading
It was strange to me that TT have 130 g/s with k03s, same with my friends A4

And now similar thing on 1kb ECU
This night MAF on friend of mine car has failed... I disconnected it, and there is a "MAF to low" DTC, but it doesen't go in limp mode. It boost and runs really fine
I don't have eather any O2/WBO2 connected to ECU( I use external to monitor AFR)

All VAG ME7 1.8T use MAF.
None of them go into limp mode when you disconnect it, it goes onto secondary load, which is alpha/n + pressure correction.
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BlackT
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« Reply #3 on: December 19, 2019, 03:31:32 AM »

But take a look at this log, when boost goes up MAF reading stay the same. And ps_w ideal follow  actual pressure, what is really strange for 20 year old car(parts on car)
And MLHFM conversion doesen't have sense. At 4 V MAF reading schloud be around 130-140 gs, and this ECU measure below 100 gs

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prj
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« Reply #4 on: December 19, 2019, 03:34:38 AM »

I am not going to look at anything, I told you how it works, there is nothing to discuss here.
Read the FR and understand what is primary load and what is secondary load.
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fknbrkn
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mk4 1.8T AUM


« Reply #5 on: December 19, 2019, 07:52:09 AM »

Actually ecu goes limp
Tslrdyn sets to max, esp not work, tev irc too
Running it mafless wo wbo2 not good idea at all
What's the question?
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RBPE
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« Reply #6 on: December 19, 2019, 08:15:15 AM »

You're asking us to summarise a large part of the FS/FR in a few sentences on what is going on, FB's just given you a breakdown and the proper way is to start looking into it as stated - quick couple of screenshots to get you going;
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RBPE
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« Reply #7 on: December 19, 2019, 08:20:32 AM »

Oops, put the NA one up by mistake!

Also, to technically answer your Q - the ecu has a number of sensors and states to fall back on if one plays up, it'll use various other functional aspects, limits and linearisations etc, to produce it's best modelled output based on it's now limited inputs. PRJ has been talking about it in terms of NA to FI for the R32T lot, SY_DSS/TURBOwhich is kinda the opposite in some respects, a lack of sensors and you can either model it to cater or add sensors - here you're looking at what's left without hfm input and a quick look at other relations like Relative Charge that they relate to. Broken's then summarised why although it may feel right, logging, knowing the system and the fact it's a nifty bit 'o' kit, is why it feels like it's working!
« Last Edit: December 19, 2019, 09:20:08 AM by RBPE » Logged
BlackT
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« Reply #8 on: December 19, 2019, 09:01:36 AM »

Actually ecu goes limp
Tslrdyn sets to max, esp not work, tev irc too
Running it mafless wo wbo2 not good idea at all
What's the question?
Everthing clear now, I only want to know what is happening with ECU
Thank you,
Thank you RBPE too
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RBPE
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« Reply #9 on: December 19, 2019, 09:21:17 AM »

Everthing clear now, I only want to know what is happening with ECU
Thank you,
Thank you RBPE too

Lol, just summarised 4 u as u wrote that!
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BlackT
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« Reply #10 on: December 19, 2019, 09:29:10 AM »

Lol, just summarised 4 u as u wrote that!
Sorry didn't understand you?
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RBPE
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« Reply #11 on: December 19, 2019, 09:34:30 AM »

Sorry didn't understand you?

 Just saying as you replied I was editing that's all;
« Last Edit: May 28, 2020, 05:59:48 AM by RBPE » Logged
prj
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« Reply #12 on: December 19, 2019, 02:58:09 PM »

Actually ecu goes limp
Tslrdyn sets to max, esp not work, tev irc too
Running it mafless wo wbo2 not good idea at all
What's the question?

The power is the same as with the MAF.
So it is not a classical limp mode.

Yes some things do not work quite right, but it never cuts power.
Limp mode refers usually to LDORXN...
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