Help! No more electricity from the alternator? Or something else?

[Jey]

Hi!

I'm stuck with my clients, fault on the car.
I have a Caravelle T6 from 2016 July.

I was driving last night when the red light came (battery logo on the dashboard).

I used my bluetooth OBD to check : 12,2v when engine running, to 11,7 then I stopped the engine.

I checked the voltage, just the voltage of the battery (+/- 12v).

I just woke up, and used VCDS.

The car is now at 289 881 Km.
71 Km ago this append (I checked on the map, it's where I had the problem):

Address 61: Battery Regul. (J840) Labels:. 1K0-907-534.clb
Part No SW: 7E0 907 534 HW: 7E0 937 090
Component: Batt.regelung H81 0744
Serial number: 0982 174161295
Coding: 330B1A73
Shop #: WSC 80093 222 69422
VCID: 688AB012E271155A873-803C

Subsystem 1 - Part No SW: 7E0 915 181 K HW: 7E0 915 181 K
Component: J367-BDMConti H03 1050
Serial number: 75410903001606170048

2 Faults Found:
02252 - Generator
012 - Electrical Fault in Circuit
Freeze Frame:
Fault Status: 01101100
Fault Priority: 1
Fault Frequency: 3
Reset counter: 84
Mileage: 289810 km
Time Indication: 0
Date: 2020.14.03
Time: 01:56:59

02256 - Quiescent Current
001 - Upper Limit Exceeded - Intermittent
Freeze Frame:
Fault Status: 00100001
Fault Priority: 7
Fault Frequency: 1
Reset counter: 99
Mileage: 0 km
Time Indication: 0
Date: 2019.14.27
Time: 01:24:51

In attached file, the full log from VCDS.
I changed the battery so maybe it's why there are so many fault (30 minutes without any battery).

Please, do you know if it means that the alternator is broken, or something else?

I'm stuck with my clients, in Lapland, far from everything.

Thanks for your help...

 

[Ricardo T]

@mmi

 

[mmi]

I changed the battery so maybe it's why there are so many fault (30 minutes without any battery).

The faults are more likely because of low voltage while driving.
Anyways, the root cause is likely the alternator not charging at all (below):
You surely have checked the auxiliary belt?

I used my bluetooth OBD to check : 12,2v when engine running, to 11,7 then I stopped the engine.

Also the fault code in address 61 suggests the same

02252 - Generator
012 - Electrical Fault in Circuit

Just to verfiy the above please see below a healthy report from address 61 - VCDS Advanced Measurements View - especially the Exciter current and Generator current should show something reasonable as below (engine running)




Address 61 has also an Output test for alternator

Values from left to right - commanded/specified voltage - actual voltage - alternator load - status

 

[Jey]

Thanks for this so quick answer.

I didn't look yet for the belt, I will go now.

Please find the 2 screenshot.

The first one is before to start the engine (the car was plugged on the 220v to charge batteries (and warmup the engine)).

The second one is engine running (without 220v).


So it confirms that it's the alternator?

There is no "fuse" ?

 

[mmi]

Edited the message to include VCDS Output test - what does that show?

 

[mmi]

There is no "fuse" ?

There is a quite hefty one- SA1 (225 A) - under battery.

T6 - VW T6 Fusebox - Fusebox/Fuse Chart SA - Primary Battery Fusebox

Fuse Chart/Listing For Fuse Holder SA - Engine Compartment Located in 'E-Box' underneath battery, this fusebox contains the primary heavy duty feeds from the battery to main vehicle equipment VIP Membership is required to download this document...

www.t6forum.com

I'm not sure about this - the "commanded" voltage is 12.20V which is below the actual battery voltage 12.416V so at that moment there was no "need" to charge. Quite possibly because the battery was just before on charge from 220V (see available battery charge)

---

Would need to force the alternator to charge at maximum voltage by using VCDS Output test

 

[Jey]

This is the result of the test. (of course I unplugged the car from the 220v).

Yes the battery voltage was over 12.20 because the car was on the 220v.
But If I unplug, start the car, the voltage is going low and low, 12.2, 12.1, etc...

Thanks a lot for your help

 

[oldiebut goodie]

@mmi - shouldn't there be some exciter current showing at start up? ( neither scans show any exciter current above ) I am wondering if it is just a case of the exciter wire has come adrift and any voltage seen from the alternator is just because the alternator has self-excited? ( I am assuming that these alternators are the same as non-smart ones and need that kick-start)
(This was a common problem on T3's where the wiring had degraded.)

 

[mmi]

@mmi - shouldn't there be some exciter current showing at start up? ( neither scans show any exciter current above ) I am wondering if it is just a case of the exciter wire has come adrift and any voltage seen from the alternator is just because the alternator has self-excited? ( I am assuming that these alternators are the same as non-smart ones and need that kick-start)
(This was a common problem on T3's where the wiring had degraded.)

Yes, agree. The exciter current indeed should be there when engine is running. And yes, I do have logs about this, too.

My understanding is that on this CXHA engine the exciter current is done internally in the alternator electronics - as the alternator connects only with hefty +B (battery) and LIN-bus - and what we see through VCDS is what is communicated via LIN-bus (yellow/green) to Battery monitor J367 (and BCM J519).




Also OP's fault code does not indicate LIN-bus failure
02252 - Generator - 012 - Electrical Fault in Circuit

LIN-bus failure would have been indicated by a different subcode. ​

02252 - Generator - 004 - No Signal/Communication​

E.g. VW TRANSPORTER 2017. ALTERNATOR NOT CHARGING. TRIED NEW ALTERNATOR, STILL NOT CHARGING.​

Thus I believe the alternator is well and alive communicating - but just not charging - because of internal failure.

Certainly would need to verify the continuity of the hefty +12 V cable between the battery and alternator.

So possibly it's a more traditional failure - worn out brushes? After all the van has almost 300.000 km (180.000 miles) on it.

 

[mmi]

This is the result of the test. (of course I unplugged the car from the 220v).

Yes the battery voltage was over 12.20 because the car was on the 220v.
But If I unplug, start the car, the voltage is going low and low, 12.2, 12.1, etc...

Thanks a lot for your help

View attachment 221142

Yes, it's obvious the battery is not charged. A bit difficult to diagnose any more remotely.

Well, if you get a chance you could record and post a blockmap data from the battery regulator (engine running) - for future reference.

VCDS > Applications > Controller Channel Map​

[Single Controller Address - 61]​

[Measuring Values]​

[CSV file]​

[Go]​

The result file blockmap-61-... will be in folder C:\Ross-Tech\VCDS\Logs\...​

​

 

[Jey]

Please, find the file.

Thanks

 

[mmi]

Please, find the file.

Thanks

Thanks - basically the same information as the fault code.

 

[Jey]

Thanks to you!

The alternator is currently being changed at the garage.

 

[Jey]

The alternator is changed, 7h of work at the garage, 1180€...
Everything works.

Thanks a lot for your help !

 

[oldiebut goodie]

All for the sake of a £1 diode most probably! I would make sure that I had the old one and check it over for obvious failed components.

 

[Howzat]

7h to change an alternator. That's shocked me.

 

[Jey]

The alternator was changed yesterday, but there is a problem.

The main battery is charging, but not the second one (for the webasto and air blowing)..
I drove yesterday evening, this morning 2h (and now I have to drive back), the voltage is 11,2v.

Please do you what could it be?
What can I check?

 

[Jey]

About the 2 batteries, are they connected together?
I'm sure not, but one friend says that the alternator charge straight the 2 batteries so there is no reason that the second battery is not charging.

 

[mmi]

Check first fuse (80 A) under left seat - (inside the red circle in the picture)
I would imagine that low charge on batteries caused quite a current draw.

The second battery charging relay is the "100" in red circle - it's active only when engine is running. So the batteries are separated when engine is not running.


Picture copied from here:

Electrical interface...What is it for?

What is the Electrical interface for external use (terminal block in driver´s seat)? I ask because I was hoping it could be a good place to wire my dash-cam in to.....Any ideas or wiring diagrams available. Thanks in advance.

www.t6forum.com

 

[Jey]

The 2 big fuses are OK :|