[spooky75]

Hello,


I have old "issue" with HVAC unit on Tiguan 2018, any time when I enable front and rear seat heaters together I get this error message:

5NB907044J SW:4501
A010C B10CD00 Function limitation due to energy management (HeckBT - Sitzheizung - Komforteinschränkung wegen Eingriff Energiemanagement)

Seat heating working on all four places despite this error, but error itself driving me nuts.
I have tested and change battery with new one, upgrade GW and HVAC modules, but still have same issue.

Can this be related to some setting in gateway somehow ?

[liviu2004]

Is there any freeze frame data?

[spooky75]

nothing special, if I delete message, just came back after next run:

Address 08: Auto HVAC (E87) Labels 5G0-907-044.clb
Part No SW: 5NB 907 044 J HW: 5NB 907 044 J
Component: AC Automat H35 4501
Revision: 20K08000 Serial number: 00000B00552633
Coding: 00020004204111011105114C1219592A
Shop #: WSC 00046 000 00000
ASAM Dataset: EV_ACClimaPrehVW37X 002023
ROD: EV_ACClimaPrehVW37X_002_VW37.rod
VCID:

Humidity sensor: exterior:

Rear air conditioning block 1:
Subsystem 2 - Part No SW: 3G0 907 049 E HW: 3G0 907 049 E
Component: E265KlimaHeck H02 0201
Serial number: 04031501850231
Coding: 000000

1 Fault Found:
655628 - Functional Limitation due to Energy Management
B10CD 00 [00001000] - -
[HeckBT - Sitzheizung - Komforteinschränkung wegen Eingriff Energiemanagement]
Intermittent - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Priority: 7
Fault Frequency: 1
Reset counter: 199
Mileage: 68704 km
Date: 2023.12.14
Time: 10:18:18

[david99]

in vcds in battery history data does it do timestamp coresponding with this entry?

[spooky75]

I will check battery history data and get back.

Meanwhile, I have tested with other HVAC module (5G1907044J sw:2010) with same coding and adaptations as original module and this message does not appear (for now).
Maybe this older SW/HW version does not support this kind of "info" messages

[david99]

I will check battery history data and get back.

Meanwhile, I have tested with other HVAC module (5G1907044J sw:2010) with same coding and adaptations as original module and this message does not appear (for now).
Maybe this older SW/HW version does not support this kind of "info" messages

I do not believe that it does not support, it may rather mean that original HVAC module have some problem.

[spooky75]

Update:
Same thing even with older HVAC module.
Nothing in battery history data corresponding to this "error".
Will check with ODIS-S and see which suggestions will be in "test plan"

[pupu144]

So, just a theory, maybe worth a shot..

According to wiring diagrams, HVAC module does not power seat heating elements directly - everything goes through J519 module. Also, there is no feedback on CAN or LIN bus from them back to HVAC.

So, in my theory, J519 monitors power flow and reports back to ECU any registered oddities..
For example, if there is some bad/loose connection, corrosion or damage in the heating element - it may cause higher resistance, and the voltage would drop. J519 would then register a low-power mode and shed load (switch off accessories, with an appropriate energy management message).

[spooky75]

So, just a theory, maybe worth a shot..

According to wiring diagrams, HVAC module does not power seat heating elements directly - everything goes through J519 module. Also, there is no feedback on CAN or LIN bus from them back to HVAC.

So, in my theory, J519 monitors power flow and reports back to ECU any registered oddities..
For example, if there is some bad/loose connection, corrosion or damage in the heating element - it may cause higher resistance, and the voltage would drop. J519 would then register a low-power mode and shed load (switch off accessories, with an appropriate energy management message).

Good idea. Definitely worth a shot. I will check connections under weekend.

Note:
I was updated BCM to 5Q0937084DG 0312 last summer and temp. reverted back last week to original SW 5Q0937084CP 0253 thinking maybe is somehow related to BCM SW upgrade.

[david99]

That is good idea with the BCM. I have currently:

Part No SW: 5Q0 937 084 CP HW: 5Q0 937 084 CF
Component: BCM MQBAB M+ H36 0253

Wanted to update as well but received advice in CT that this BCM HW version will not work well with higher SW. So there is possibility that this is connected really with the update itself.