MID 128 SID 231 FM2 error code.. what does it mean and how to fix it??
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@ Pablo UA Please Help if you can so I can deliver supplies to people in need at this crazy times.
Truck is 2005 Volvo VNL 630 with D12 Volvo engine and Eaton Fuller 3 pedal transmission.
I tested diagnostic port pins C and D( yellow and green data link) and its 60 Ohms with key off and 0 with key on.
I changed XY shifter and TCU 2 years ago. Didn't change key pad(gear selector yet ). But tested all 3 comonents 2 years ago and they found 2 components to be bad.I took them out my self and brought them to testing facility in MI where they tested them in chamber using temperature and vibration.
I can't find where the fault is coming from.
I have same MID 128 SID 231 FMI 2 that is intermittent.
Sometimes would trigger tranny code and Vehicle sometimes only Engine ECU.
When I run tranny troubleshooting I came up with Fault Code 35: J1939 Data Link
I traced and inspected all data link wires(yellow and and green) inside truck, changed TCU harnes that goes to batteries and key pad and sensors..
My mechanic checked the same and all the connection under the fuses but couldn't find anything.
Does this sound more like engine ECU or Engine harnes or transmission problem?
Any help would be appreciated.
Thanks in advance.
IvanLast edited: Mar 18, 2020
Pablo hasn't been around in years. If you have the Eaton UltraShift, chances are your problem is in the wiring harness that runs under the floor mat on the drivers side. Eaton recommended to Volvo that they run the harness outside the truck, but Volvo ran it inside under the floor mat. Water gets under there and sits and the harness wires corrode and break. We have a fleet of 30 '07's and every single one of them has had that harness repaired. Some multiple times. When I get tranny codes, that's the first thing I look at now.
All the wires look like brand new and couldn't find any bent, chaffed or broken.
I noticed that my problem is temperature dependent. If I drive truck for the first hour I would have inactive codes but no problems shifting. But if truck was driven whole day it would develop hard shifts. Service light on key pad(shifter) and it wouldn't go out of the gear when trying to downshift by itself.
The other day I lost speedo reading. It would show 35 mph while I am driving 70mph.
I am suspecting TCU but will change both speed sensors just in case.
TCU just got price increase since this is old equipment and they(Eaton) is outsourcing it.
I paid $1012 for rebuilded TCU (Wheeler truck parts) 2 years and 3 months ago and now new price is $1912.
Warranty is only 1 year..
Original lasted for 13 years..
Any thoughts would be appreciated.
Speed sensor changed but still have codes for Data Link MID 128 SID 231 FMI 2Last edited: Apr 2, 2020
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