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Lou P. master tech
Lou P. master tech, Mercedes Technician
Category: Mercedes
Satisfied Customers: 3726
Experience:  15 years master certified 100% fix rate and have access to factory radio codes, wiring, and instructions.
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I have a 2002 E320 wagon. The transmission will not upshift.

Customer Question

I have a 2002 E320 wagon. The transmission will not upshift. I have replaced the conductor plate, the adapter plug and of course the filter and fluid.
The codes that are up are: P2503;P2500;P2502;P2600. Using the OBDII scanner I get PO730. I have read that most or all of these could be related to insufficient battery voltage. I checked the battery, and read 12.15 static voltage. I'm now charging it, but I'm not sure that the battery is the culprit. I charged it earlier today and with 12.4 it did not correct the problem.
What do you think. What can I try or test?
Lawson
Submitted: 1 year ago.
Category: Mercedes
Expert:  Lou P. master tech replied 1 year ago.
Hello my name is ***** ***** i will do my best to help you , i strive for EXCELLENT service and nothing less. You most likely have fixed the issue. However you need a scanner that can read and erase the transmission control module memory. The standard obd2 scanner cannot access the trans module to erase the codes so the module will still be in limp mode. Hope this information helps. Please take a second and click the box and rate my service GOOD OR EXCELLENT SERVICE if you feel I have been helpful and please request me in the future. If you feel I have not been helpful please DO NOT RATE BAD OR POOR AND WASTE YOUR MONEY , I will opt out to see if another expert can provide more or better assistance so you're not wasting your money!!. Thanks for choosing just answer. Lou. also , if you feel i deserve one , BONUSES are GREATLY APPRECIATED ! 😉 Keep in mind then when you rate it does not end our conversation. you can still return here to me for follow up information if needed, Lou.
Customer: replied 1 year ago.
I will have codes cleared and then give you the result
Thanks
Expert:  Lou P. master tech replied 1 year ago.
Ok. Again codes must be cleared with a Mercedes Benz comparable scan tool like a snap on verus
Customer: replied 1 year ago.
Hi Lou:
I was just able to get codes cleared. No change. Sill won't shift out of 1st gear. Other ideas? I read somewhere that the shifter may have an inside module and that was a possibility.
Expert:  Lou P. master tech replied 1 year ago.
That very well could be but what kind of scanner did you use ? It cannot be a simple read/erase type of scanner. It has to be one that can access the control module for the transmission
Customer: replied 1 year ago.
They were cleared with a Snap On tool
Customer: replied 1 year ago.
the tool was connected to master plug in fuse box under hood.
Expert:  Lou P. master tech replied 1 year ago.
Ok. What codes came back. Sounds like the scanner is the correct type.
Customer: replied 1 year ago.
After we cleared the codes I came back to my place. No lights are on except the abs asr lights.
Customer: replied 1 year ago.
Can you look at the wiring diagram and see if there is a shifter control module in the shifter?
Expert:  Lou P. master tech replied 1 year ago.
There is a control module inside the shifter. The shifter itself is a control module. Do the gears match on the dash with the shifters actual position ?
Customer: replied 1 year ago.
Yes
Expert:  Lou P. master tech replied 1 year ago.
Ok then the shifter is most likely fine. What codes are you getting from the abs? The brake switch is the most common failure.
Customer: replied 1 year ago.
My scanner won't read them
Expert:  Lou P. master tech replied 1 year ago.
Oh gotcha. Ok. Well you can do one of two things. Try a new brake switch or get th codes read and let me know the codes.
Customer: replied 1 year ago.
No problem replacing the bls, and I will do it as I have done on cars with the same lights popping up. I just don't think it is related to the current overriding problem, no upshift.
Expert:  Lou P. master tech replied 1 year ago.
You are most likely correct BUT without knowing the fault codes we can guess for days. If the gear shift in the dash matches the shifter then I highly doubt the issue is with the shifter. If it was the dash would not display D. It would blank out.
Customer: replied 1 year ago.
Just read codes again; P2503 and P2600
Expert:  Lou P. master tech replied 1 year ago.
Ok thanks. Give me some time to check those out.
Customer: replied 1 year ago.
Tested battery under start load..dropped to 9.5V. Replaced battery.
Expert:  Lou P. master tech replied 1 year ago.
Ok good call. I may have to return in the morning if that is ok
Expert:  Lou P. master tech replied 1 year ago.
Assuming you have replaced the battery have you erased the trans codes and drive the vehicle again ? One code was for voltage and the other was for trans slipping. What is the current status ?
Customer: replied 1 year ago.
Today, I installed a known good tcu and it made no difference. Do you know if the tcu removed from another car has to be reprogrammed to be recognized by the ecu in the ailing car?
Expert:  Lou P. master tech replied 1 year ago.
Well here's the thing with trans modules is they learn the way the current trans shifts and it sets up a matrix of shift points and when you swap it to another car you actually can make it worse as it will not relearn until forced with a scan tool. And a vin is coded but I believe it will still function.