VW CARAVELLE 2,5 petrol AVT

[Orchid70]

Hi
I have a problem and not sure where to go exactly.
T4 2,5 petrol, AVT year 2001.
VIN: WV2ZZZ70Z1H108351
Reading (the three fault codes come back in different order, sometime all, sometimes without cylinder 4 misfire)

Friday,06,November,2020,10:28:33:18201
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 7 x64
VCDS Version: 19.6.2.0 (x64)  HEX-V2 CB: 0.4508.4
Data version: 20190930 DS308.0
www.Ross-Tech.com


Dealer/Shop Name: Firma Johannes Bruun 
Workshop Code: 000 02013 000000


VIN:    License Plate: SFT984
Mileage: 213360km-132575mi   Repair Order: 






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Chassis Type: 7D - VW Transporter/Multivan (1996 > 2004)
Scan: 01 02 03 08 15 17 18 19 22 25 35 37 56


   Mileage: 213360km-132575miles
-------------------------------------------------------------------------------
Address 01: Engine        Labels: Redir Fail!
   Part No: 023 906 033 B
   Component: 2.5l/2V SIMOS3  00HS3603  
   Coding: 00001
   Shop #: WSC 00000  
   VCID: 0C41A66AEF5F26F7A5F-51CE


3 Faults Found:
16514 - Oxygen (Lambda) Sensor B1 S1 
            P0130 - 35-00 - Malfunction in Circuit
16688 - Cylinder 4 
            P0304 - 35-10 - Misfire Detected - Intermittent
17834 - EVAP Purge Valve (N80) 
            P1426 - 35-10 - Open Circuit - Intermittent
Readiness: 0010 0001


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Address 15: Airbags        Labels: 1J0-909-60x-VW3.lbl
   Part No: 1J0 909 603 BL
   Component: AIRBAG VW3 -        V04  
   Coding: 16972
   Shop #: WSC 02743  
   VCID: 74B1DE8A97AF5E37DDF-4B9A


No fault code found.


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Address 17: Instruments        Labels: 7D0-920-xxx-17.lbl
   Part No: 7D0 920 803 
   Component: T4-KOMBIINSTR. VDO V22   
   Coding: 01151
   Shop #: WSC 00000  
   VCID: 619FA7DE385DDB9FA69-5160


No fault code found.


End----(Elapsed Time: 03:08, VBatt start/end: 12.1V/12.0V. VIgn 0.0V)------

When the owner bought the car and first got Engine light he came by to read the fault codes:
Lambda code was present.
And 4 cylinder missfire.

So I have changed the first lambda.
MOT didnt pass due to high emissions.

After that the lambda code and EVAP code came.
I checked the charcoal canister solenoif next to lambda connector. Solenoid OK.

After that I started to measure wires:
Both lambdas 12V wire (the white/red)
MAF sensor 12V wire
EVAP solenoid 12V wire
They all are connected to each other before going through the torpedo wall into the cabin.
All have 1,9 ohm resistance to ground
Only couple of mV with ignition on.
I cannot follow the white/red wire with tone generator.

BUT - when I took out the S117 fues (right one, above the relay plate inside cabin) The resistance went to infinite.
And the tone generator OK.
I could not find any damage in the wiring in the engine bay.

When I connect the tone generator to the other wire (blue/red) from the fuse S117 - the tone is missing.
So the problem must be somewhere after the fuse.
Here it gets trickier to follow the wire.

I did take the fuel pump relay in and tested it.
OK.

And then I realised - I should measure voltage with engine running:
At lambda voltage - 14,2V - so OK.

So I measerued resistance on wires between G80 and Lambda and ECU.
All wires to ECU had 0-0,2 ohm resistance. So OK.

Is it the ECU??

Pics of wiring:

[Orchid70]

Now I have had all the pins out in the connectors to prelambda and evap solenoid - as well as the corresponding pins on ECU side are checked - they all are OK.

Would the intermittent fault on missfire on cylinder 4 also indicate towards ECU? Its a Simons 3.5.
Perhaps I should take out the oscilloskope and see how that injector behaves?

[Orchid70]

I think Im getting closer now.
What do you think of these spikes at over 50V to EVAP solenoid??

[Orchid70]

Those spikes above would be the normal inductive kick from the solenoid coil.

But:


I think I have found the cause for the P0130 at least.


Measured voltage to heater element on pre cat lambda - engine running:
Ground from ECU


Voltage on B1S1 O2 with ground from ECU - YouTube

Following is with ground taken from battery:

Voltage on B1S1 O2 ground taken from battery - YouTube

It looked like the fault code was set when the voltage got under 10.5V.
The warmer the enigne got - the higher the voltage got - or the ground was better.