Sharan 1.9 TDI AHU limp mode

[Sharan1998]

VCDS Lite shows: 65535 -  Internal Control Module Memory Error
            35-10 -   - - Intermittent

I have strange feeling around my anus, that MAP sensor in ECU is blind. Does fully registered VCDS-Lite shows MAP sensor readings in some group?

[johnnyroper]

Yeah registered copy will give map readings in measure blocks.
I take it that was in engine controller? A quick google shows it is more airbag controller related?

[Sharan1998]

Yeah registered copy will give map readings in measure blocks.
I take it that was in engine controller? A quick google shows it is more airbag controller related?

Address 01: Engine       Labels: 028-906-021-AHU.LBL
   Controller: 028 906 021 GS
   Component: 1,9l R4 EDC   00SG  1904
   Coding: 00002
   Shop #: WSC 00020
   VCID: 66BF4A4E117F
2 Faults Found:
65535 -  Internal Control Module Memory Error
            35-10 -   - - Intermittent
00575 -  Intake Manifold Pressure
            17-10 -  Control Difference - Intermittent
Readiness: N/A

Is it MAP actual or MAP specified or...?

[Chrispb]

Early cars have the engine ECU behind instrument cluster with the MAP sensor inside and has a small hose connected to it which goes to the air charge pipe.
On the inside of the ECU there's a short piece of hose that perishes with age.
This can be sorted but requires removal of the ECU to access.

[johnnyroper]

Address 01: Engine       Labels: 028-906-021-AHU.LBL
   Controller: 028 906 021 GS
   Component: 1,9l R4 EDC   00SG  1904
   Coding: 00002
   Shop #: WSC 00020
   VCID: 66BF4A4E117F
2 Faults Found:
65535 -  Internal Control Module Memory Error
            35-10 -   - - Intermittent
00575 -  Intake Manifold Pressure
            17-10 -  Control Difference - Intermittent
Readiness: N/A

Is it MAP actual or MAP specified or...?

Registered will give specified and actual MAP reading.

[Sharan1998]

"Mouthtested" the pipe going to ECU from motor side - ain't leaking. VCDS Lite shows MAP actual and MAP specified numbers running. EGR duty cycle is about 19% and boost control(?) is 91 and something %. When speed is rising to about 85 km/h, MAP actual jump ower 1900 (mbar?), EGR duty cycle is going ower 50% and boost control under 70 %- back to normal readings just after switch off and start again.
Just sucked the pipe going from air cleaner to some valve (18?) from air cleaner end - ainÃ,´t holding vacuum inside.

[Chrispb]

Maybe but those are the error codes received when pipes perished

[Sharan1998]

AHU wastegate actuator - operated with vacuum or pressure?

[johnnyroper]

Think it is vac operated via the n75 valve, if memory serves correctly iturbo is standard wastegate and not vnt.
Trace vac pipe from turbo to the n75 and check for splits etc,you can also activate n75 with vcds to make sure it is operating.
Have you checked basics like good vac from the pump and condition of all vac pipes?

[Sharan1998]

Mmm.. actuator is a pressure operated, pipe from turbo thru n75 to wastegate actuator. I connected the pipes straight with eachother. Nothing changed - wastegate stucked?

[johnnyroper]

Is it defo pressure operated? What is routing of the pipe to the n75 is it off the vac pump pipework or from side of turbo or inlet manifold?

[Sharan1998]

http://www.vwt4forum.co.uk/picture.php?albumid=18698&pictureid=175182

Connected the pipes straight from turbo to boost control valve. Like the old school TDI-s had.

[Sharan1998]

http://pics.tdiclub.com/data/516/A3_98_Jetta_TDI_Pressure_Vacuum_Diagram.jpg

[Sharan1998]

Wastegate working on 0,5 bar(loaded manually).

[johnnyroper]

What you are looking at is either map sensor issues causing ecu to operate n75 at incorrect time. Check the pipe in ecu as suggested. Or the n75 is is sticking in my opinion.

0.5 bar opening of wast gate is about normal for ahu so to have map spikes and limp mode activated it all points to 1 of the above being at fault.

[Sharan1998]

Wastegate was stucked(moving much easyer after oiling). VCDS shows MAP actual numbers running up and down. Changed just pipe from turbo to n75.

To be continued...

[Sharan1998]

All pipes, belonging to n75 was changed. Wastegate is fine. Nothing changed.
Big boys says that MAP sensor inside ECU is not blind. Blind is barometric pressure sensor. Gives 1080 mbar when engine started and when start driving goes to 693,6 mbar and stays until motor is switched of. Your comments, please.

[johnnyroper]

Have you checked the internal MAP sensor pipe in ecu? Itââ,¬â,,¢s showing all signs of it being perished/split affecting readings.

[Chrispb]

Have a read here.

http://www.fordgalaxy.org.uk/ford/index.php?/topic/22717-how-to-ecu-removal/

[Sharan1998]

Internal MAP sensor gives good numbers. I "mouthtested" the pipe going to the ECU - its fine. VCDS understand when i disconnect the pipe from manifold.
Big boys says, that replacing barometric pressure sensor cost 90 EUR. Remove ECU, post it to them, and next day they post it back.
If we take a look at this diagram - http://pics.tdiclub.com/data/516/A3_98_Jetta_TDI_Pressure_Vacuum_Diagram.jpg we can see, that atmospheric pressure sensor(barometric pressure sensor?) is in valve n18 and a wire goes from n18 to ECU. Any ideas?

[johnnyroper]

I donââ,¬â,,¢t think you will find atmospheric pressure is measured by N18 that pipe back to air filter is just the N18 vent thatââ,¬â,,¢s used to release the vac so egr valve closes when demanded

[johnnyroper]

You say you mouth tested it but will that prove the pipe inside ecu,can you apply up to 19psi with your mouth?
As already said a few times you need to take the ecu out and physically check the internal pipe to map sensor.

[Sharan1998]

Just loaded pipe to MAP sensor with 1 bar - pipe is fine. Motor going to limp mode, when difference between specified and actual MAP rise to about 400 mbar. Specified 1300mbar - actual 1700mbar. Actual canÃ,´t rise so high when pipe is damaged.
When pipe is damaged, then specified is higher then actual, right?

Baro readings are poor - 693,6mbar. Need to be about 1010 mbar.

Question is: are the BARO sensor in same household with MAP sensor?

[johnnyroper]

I go back to n75 sticking or the wastegate actuator not operating correctly then if you are having overboost. You need to try a new n75 in my opinion.

[Sharan1998]

Going limp mode when boost is about 1700mbar. Is it too high?

[johnnyroper]

Thatââ,¬â,,¢s about right as the ecu accounts for slight spikes before it limps.