[Adam Zajdlicz]

I have bought Fortwo 453 EQ with damaged internal DC/DC converter (for the 12V battery charging). Car is still able to drive (after external charge of the 12V battery) but the HV battery is almost completely drained - 0% SoC, 330V. It may be question of days that the HV contactors will not close any more and I'm affraid the battery will be bricked or damager pretty soon. The dealer (authorised MB seller, wtf) lied to me, that there is no issues with HV battery charging. But it seems, the DTC code caused by faulty DC/DC converter, locks the charging HV possibility (safety, who knows...).
Necessary element looks like this. Maybe someone has something like this or knows where it's possible to get it.

Official MB statement is, I have to buy a complete engine. It costs about 7000 Euro. Ridiculous...

What I can say more? It communicates by LIN interface directly with inverter module, which is also placed inside of the big aluminium alloy box that "surrounds" the engine. Except HV +/- and 12V output, it's connected with 3 small wires. I tried to see, what could happen inside of the module but everything seems fine. Xentry report something, what can point on the internal flash memory checksum error, so no fix possibility I guess.

By the way, I would ask for some other things:

• What is difference between 5AL-604 (my) and 5AL-601 engine?
• Does anyone have a schematic or service manual for 453EQ (like there is a nice one for 451ED)?
• Does anyone have an experience with replacing it? I see similar device on Ebay but with difference P/N and software number. I don't want to pay $1000 for device that will not work because of the software incompatibility.

If there is anything I can take a picture or something, related to disassembled HV block of 453 EQ, just ask me.
Thanks in advance for any help.

 

[Adam Zajdlicz]

I just wanted to add, the registered DTC codes are: P085296 and P0852F1.

 

[DudeInTheSmart]

There are people in Eastern Europe that have reverse engineered this. Read some of the other battery threads for contact information. Try @GoSmart Service

 

[Adam Zajdlicz]

I think they have more urgent topics right now in Ukraine. Generally, no other answer than "replace the DC/DC". As the DC/DC converter part is completely unavailable as stand-alone part and a complete engine costs a lot, I'm still trying to fix it.

Does anyone have a binary content of 24C02 EEPROM chip located in the DC/DC device?

 

[Adam Zajdlicz]

The car is already fixed. I couldn't buy separate DC/DC unit, so I had to pay a bit more for a complete HV management unit. Important notice: DC/DC unit with number 292A01843R marked as SG and taken from 5AL601 engine, is also compatible without any issues.

 

[fotoperusrl]

Hi Adam, I GOT the same problem with an smart fortwo ED 451. I opened the HV battery and charged It manually till 330 vdc slowly and carefully, because was totally drained because of the 12 vdc. The problem is to charge With j1772 plug I cant as I GOT error Sysengineoff. sonthr temporary solution is using jumpstart to overload 12 volt battery till 13.x volt . Then after 15 minutes waiting i switch on, get ready, i listen contactors run again , then switch off With key, close Door, then It allofdhere d to charge the car again. But another days the same issue.
Do you think this error is really a dcdc problem?
Where
What do you mean changing complete HV management unit? Inside the HV b24€

 

[Adam Zajdlicz]

Hi Adam, I GOT the same problem with an smart fortwo ED 451. I opened the HV battery and charged It manually till 330 vdc slowly and carefully, because was totally drained because of the 12 vdc. The problem is to charge With j1772 plug I cant as I GOT error Sysengineoff. sonthr temporary solution is using jumpstart to overload 12 volt battery till 13.x volt . Then after 15 minutes waiting i switch on, get ready, i listen contactors run again , then switch off With key, close Door, then It allofdhere d to charge the car again. But another days the same issue.
Do you think this error is really a dcdc problem?
Where
What do you mean changing complete HV management unit? Inside the HV b24€

The car is already fixed. 12V battery was charged externally but I didn't helped fof HV charging. I couldn't open the battery because battery itself is still on guarantee.

451ED and 453EQ are completely different cars with different powertrains. HV block in 453EQ is a big aluminum alloy box which contains HV charger unit, inverter and DC/DC converter. Additionally, some HV fuses for heater and AC compressor, DC link capacitor, etc.. There is a huge difference between HV block for different HV charger power varians (6 or 22kW). Fortunately for me, the DC/DC is exchangeable between them (despite of different part numbers).

 

[swf]

Hi, Adam. Do you want to sell this broken HV Block? regards