Ohtwos500

Finally figured out my p0600 code. ECU looked good and dry and read that the 600 code could be for the tcu so i found the tcu and removed it and a ton of water poured out. So i thought it was cut and dry the tcu was bad. Found a good ebay seller that had one with the same exact part numbers so i bought it and installed it yesterday. Now the gear selection indicator works in the dash as well as the engine and abs light and all are gone. Thats all good and all but the trans still does not shift!!!! Still stuck in limp mode 2nd gear. Other thing i notice is the triptronic 1-5 thing does not work nor does the s/w switching.

So.....is this as simple as every tcu needs programmed? Or is it a bad tcu? Not the right tcu? Is there a simple learn procedure you can do yourself?

This issue has really put me in a bad way the past couple weeks.

Colin Frolick

Probably need to reset limp mode and code the new tcu with a star tool.

ibeforreal

You need to either take it to a MB dealer or find someone with a STAR diagnostic computer to reset it. Nothing else will work. It should be less than $200.

Ohtwos500

Thank you, where im located theres not much of that kinda stuff in the area. This is bad, the car only goes about 40-50 max so i cant really drive it to a dealer. So i understand this correctly the tcu needs to be programmed to the vin/specific car correct?

ibeforreal

It has to be reset to let the transmission know that everything is back to normal. They are designed to go into limp mode in order to not cause further damage to the transmission.

Ohtwos500

Im someone who likes to understand how things work so sorry for the questions but what your saying is the tcu does not need programmed, it just needs reset? But why would the new tcu i installed need to be reset? Also, so your saying a benz repair place/dealer or someone with a star diag tool is the only way ill be able to reset it correct? Im asking so when i do in fact find someone i can tell them what i need done.

ibeforreal

In your original inquiry you sated that when you opened the TCU "a ton of water poured out". In addition to the TCU you might want to clean your reed valve to make sure it is clear of debris such as leaves, sand, dirt, etc. If that thing fills up it will cause you a multitude of problems including water leaking into the car (passenger side US version) and eventually screwing up all the electronics.

Now as far as the TCU is concerned:
The transmission has stored error codes. They have to be cleared and the new/used TCU has to be matched to your car. A typical OBD scanner will not be able to do this. It will take a STAR DIAG tool. Just tell them that you replaced your TCU and need to have the error codes reset so that the transmission will recognize that the problem has been fixed.

Ohtwos500

I geuss it does seem like its in a protection mode because the w/s switch stays on w and wont let me switch to S. The trans is stuck in 2nd gear and the triptronic does not work, meaning when moving shifter side to side numbers do not show up it just stays on D.

Does this sound like limp mode ? Not likely the tcu i bought is bad is it? I would just hate to have to go through the program process at the dealer to find the tcu i bought is bad.

kraut56

did you read post # 7????

Ohtwos500

I did read it. What im asking is if what i described sounds like a tcu that just needs reset or if the one i installed is possibly bad.

ibeforreal

You will never know until you have it reset with STAR.

Ohtwos500

Dealer says that a tcu is coded to the vin and a used tcu cannot be recoded to a different vin. Is this true? if so im going to have to return the tcu and part out the car.

ibeforreal

Does the TCU you purchased have the same exact part number as the one that was in your car, and did it come from the same model year?

ibeforreal

Watch this video. It shows how you can test your TCU to make sure you are getting the correct amount of voltage.

Ohtwos500

The tcu does have the same exact sets of numbers yes.

I have a tuner with a star coming to me today for programming for 120.00 dollars.

Can anyone tell me what needs or can be done to a tcu as in does it need reprogrammed? Can a tcu be programmed or does it just need reset?

I just want to make sure he knows what hes doing

ibeforreal

Once he links up the STAR machine the error codes will show up. He will need to clear the error codes for the transmission and see if any others appear.

Ohtwos500

Well it never worked out gettin hooked up to a star so i exchanged the tcu for another from the ebay seller i purchased from and car is workin great now fyi

ibeforreal

Great news. Glad you were able to get it working.