7D - Auxiliary heater malfunction

Code:

Adresse 7D: Zuheizer       Labeldatei: RKS\1K0-963-235.lbl    Steuergerät-Teilenummer: 1K0 963 235 E    HW: 1K0 963 235 E   Bauteil und/oder Version: PTC-Element         0404                  Codierung:             Betriebsnummer: WSC 00000 000 00000                       VCID: 2D5A8A1FCD81 1 Fehler gefunden: 00361 - Heizelement für Zusatzheizung (Z35)         014 - defekt

The error cannot be deleted.

Does that mean the whole thing needs to be replaced for 305 euros, or are there other reasons?

I'm asking this question in such a silly way because the error only appeared after the battery was replaced after 5 and a half years... (of course, according to Murphy's Law, that part *must* have been fried, or something like that!?)

Regards,
Pete.

Okay, regarding the actuator diagnosis, I can turn the PTC element on and off; it then draws power, and it also gets quite warm in the area ...

Nevertheless, the error remains, and when attempting to delete it specifically in the control unit dialog, the message appears that I should contact Ross-Tech.

Hi Pete!

What I'm noticing during the scan: No encoding is present, and the WSC value is set to 0000...

If you try to code it, what happens?

And one more tip: In VCDS, under "Settings," set your WSC (Write/Read Security Code) to something other than 0000. This often causes problems when coding, especially with certain types of security tokens.

Best regards from Munich!

Coding is not possible (the button is disabled).

Ugh... You can't just easily remove that part; it looks like you'd have to disassemble half the car to get to it – especially with these temperatures (in an unheated garage)! And all of this just because some poorly designed chip is acting up. There can't be that much broken if I can still communicate with it via CAN, all the data blocks are coming through, and it can still be turned on and off...

Hello again!

WSC changed in VCDS or something other than "0000..."?

Best regards from Munich!

DieselBär30x wrote:

Hello again! WSC changed in VCDS or something other than "0000..."? Best regards from Munich!

If coding is not possible on the control unit, then the WSC cannot be changed either.

Hey dude!

...okay, there might be something to that...
You are right .

Best regards from Munich!

Unfortunately, there is no visible direct damage (such as a scorched component or similar).

Well, let's start with some chip identification and gradually get used to the idea of spending 305 euros...

Did you only expand it because of the error? Or did it not get warm inside anymore?

RedR32 wrote:

Did you only take it apart because of the error? Or did it stop getting warm inside?

The latter. I've been wondering for a while now that it sometimes gets quite warm very quickly, and other times it takes forever. I hadn't even thought about the auxiliary heater. I only noticed the error after replacing the battery, when I was trying to clear the usual error codes, and it was stuck at code 7D.

The inconsistent behavior could also be due to the already weak old battery, as the auxiliary heater is controlled in a rather "unintelligent" way.

Removing the trim pieces is a pain, but I'm used to it; this isn't the first time . I'm just annoyed that this process is much easier on the sister model, the Golf, but on the A3, you always have to remove everything. Actually, I should also replace some of the climate control actuators because some of them are constantly ticking (a known problem; there are updated versions available). But for that, much more needs to be...

Basically, I'm just curious... Now I'm going to take a closer look at the circuit board (checking for hairline cracks, temperature issues, etc.). The heater itself is quickly installed or removed; the car also runs without the cover parts ...

Hi,

Quote:

Basically, I'm just curious

.

That's also good.

Contact Ross-Tech, also Kaufmann.

Here's a small tip from me on how to save money:
At least in the Passat 3C, the auxiliary heater including the control unit is only included in the first model year. The STG is known for its tendency to fail.

In later model years, the PTC heater will again be controlled using two relays. Since the three PTC elements themselves don't fail, you could switch to the relay-based system and save money that way. The outer rods provide the high heating power, while the inner rod provides the low heating power.

Refer to the wiring diagram for the newer model year for the remaining information.

I don't know if any more coding needs to be done.

Greetings.
Guste.

guste100 wrote:

Here's a small tip from me on how to save money: At least in the Passat 3C, the auxiliary heater including its control unit is only installed in the first model year. The control unit is known for failing. In later model years, the PTC is controlled again in a clumsy way using two relays.

Thanks for the tip. Yes, when I contacted the seller, he wanted to know the chassis number (even though I had only inquired about the "E" version mentioned above...). Audi probably switched to relays in the A3 at some point as well.

Under [url][/url] or [url][/url], you can see the whole range. The STG variant is the "top"-of-the-line model...

Currently, I've ordered some Power MOSFETs (they only cost 4.50 EUR). If replacing the MOSFETs doesn't solve the problem, I'm considering the relay option, although I would need to figure out a) who will drive the relays and b) how to securely attach the rather thick cables to the PTC elements without the car potentially catching fire .

guste100 wrote:

I don't know if anything else needs to be coded.

Okay, in the CAN gateway, "7D" needs to be disabled. That would also be my Plan C: simply deactivating the heater – I've already removed the 100A fuse in the engine compartment.http://www.beru.com/de/produkte/elektronik-und-sensorik/heizelemente-ptc{MARKER}http://www.beru.com/download/produkte/prospekt_ptc-neue-generation_de.pdf{MARKER}

Brief feedback... It wasn't the MOSFETs.

Desoldering the components was a risky endeavor, as the circuit board is glued to the metallic base with thermally conductive adhesive, and even with significant heating, it is very reluctant to detach. However, desoldering is impossible without doing so, as the metal acts as an excellent heat sink. After replacing the MOSFETs, the same problem persisted, as indicated by VCDS. Furthermore, the thermal resistance is likely significantly higher than before due to the action taken (obviously: there's not enough solder under the MOSFET, and the thermal paste also needs to be replaced), so I'm not going to risk running the device.

End result: Disassembled. Opening with blind cover closed. Disconnected from the CAN gateway.

Tip: Check MELFs, see below.
Okay, I'm ready. Please provide the German text you want me to translate.