Serial numbers on TCM explained

[MilesMurphy]

Hi guys,

I have a e280 with a bad tcm. Looking to replace with an exact match. But does anyone know what some of the numbers reference.

 

[AMGeed]

Can't help with most of those numbers, but the only one to be concerned about is making sure you get exactly the same Part#
A 030 545 23 32
I'd imagine the majority of those numbers are relevant to Siemens the manufacturer.

Plenty of used ones on eBay with that Part#

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[rich.g.williams]

Hi, having exactly the same part number is not enough as the same part number is used for different models (and there are a few part numbers).

What's important is that the replacement has the same part number and comes from exactly the same model car, for example my car a 2003 C200 Kompressor Coupe the TCU part number is A032 545 12 32 but the same part number A032 545 12 32 is also fitted on a 2004 C320 SE this TCU would not work on my car.

I'm not saying that for your car with TCU A030 545 23 32 a TCU from a different model car but with same part number cannot be re-coded (firmware updated) to work with your car - just you need someone to do the firmware update.

Be aware also that if for example you were to disconnect the wire from say the TCC (torque converter clutch) solenoid the TCU would go into limp mode three times and on the third occasion it would brick itself - again you would need someone to code it to get it working again.

In fact its worse than this, if you simply power the TCU up on the bench three times it will brick itself, inside there is a serial flash memory chip and a parallel flash memory chip, technically it is possible to read from both chips and copy across to a second TCU but in doing this the TCU will be powered up and brick itself, very hard to clone firmware across to a second TCU.

Here is a summary of roughly what the various numbers are about:-

1. A032 545 12 32 - Mercedes part number
2. EGS52 - This is the hardware design all EGS52 have the same hardware inside (same chips, same PCB)
3. HW: 03/01 - Sub version of hardware, maybe small PCB differences, connector differences (I think)
4. SW: 42/01 - Base Firmware version (I think)
5. no number shown - Specific configuration information pertaining to car model etc.

So you need same part number A 030 545 23 32 from exact same model car that had a known working transmission.

Photo of what's inside an EGS52:-




Regarding your "e280 with a bad tcu" very unlikely that your TCU has a hardware fault, far more likely is that a wiring fault has let the TCU brick itself. Also your existing TCU can be brought back to life by someone with good knowledge of Star system, coding and firmware etc.

Also if you get a new TCU be extra careful that wiring to your transmission is good and all solenoids are electrically good and connect electrically to the TCU.

PS TCU TCM ETC all the same thing - an EGS52 unit.

Here is the TCM connector pinouts and the Pilot Bush pinouts:-

 

[MilesMurphy]

Many thanks for the info, very informative