5 replies to this topic

[MattyM]

So I've been doing research on the AW50's TCU module. Im getting very interested in trying to
modify the firmware. I havnt had time to break open the box yet and see what it contains. I thought
I'd start a discussion so we could discuss modifying the firmware.

I found these links very helpful:

http://www.volvoclub...nsDiagnosis.pdf

All about the transmission and TCU

http://www.___.com/f...f2c9d275661979e

How the TCU works

http://www.volvoclub...ingDiagrams.pdf

TCU wiring

http://trionic.mobix...otronic 4.3.pdf

Various info about motronic wiring

The TCU seems to be a very simple system and probably easy to reverse engineer.

This is how it all works (I think):

The TCU has inputs for various sensors like Vehicle Speed, Engine Speed, Throttle Position, ETC

What the TCU does to drive and shift:

1. Checks if the brake is pressed, enables PNP switch so the shifter can switch
2. Reads the Gear Position Sensor to determine which gear is selected.
3. If put in Drive checks driving mode (Econ, Sports, Winter)
4. It then uses the various sensors to calculate the gear
5. Outputs to shift solenoid no 1 or no 2 and this tells the transmission what gear to change to
6. Check if we need to go into Lock-up mode (Lock-up solenoid)

Shifting while moving:
1. Uses various sensors the calculate gear
2. Torque Limiting line (B2) is set to high to tell the ECU to cut ignition (torque)
3. The TCU recieves an OKAY (High) from the ECU on pin B4.
4. If in Lock-up mode, unlock (Lock-up solenoid)
5. Shift gears using solenoid
6. Send HIGH on line b3 to tell the engine to re-engage torque (i think this step is right, but i dont know for sure). Help?!

This is what I have digested so far. Using this info I believe it wouldnt be too hard to reverse engineer the system
and use a more modern Microcontroller and possibly setup Paddle Shifters, etc.

Connections from the TCU to ECU (There are only 8):
B1 (Cant figure this one out)
B2 (Torque)
B3 (Torque)
B4 (Torque ACK)
B12 (Engine Load)
B14 (Gear Position Sensor)
B15 (Cant figure this one out)
B20 (Throttle Position Sensor)
B22 (Cant figure this one out as well)

Hopefully soon i can tap into some of these lines and read the voltages and see what everything is doing when im driving.
Also im looking at buying another TCU to disassemble and decompile the firmware. Im also doing some research on possible
microcontrollers to use for a homemade TCU. The hardest part of the homemade TCU will probably be diagnosis. Either way
I have figured that paddle shifters and finally possible.

Thanks! Hope most of this info is right and if it is not then please correct me!

[Zappo]

http://volvospeed.co...36#entry2029836

[MattyM]

Zappo, on 30 January 2012 - 01:06 AM, said:

http://volvospeed.co...36#entry2029836

Yup! I read that zappo! I believe Lucky said he was going to release all of his research to the public. I decided to create another thread to do more with creating a reverse engineered version of the TCU. Also because Lucky said he was delaying development until ME7 was 100% done. I thought in the meantime i could get some info together.

[jnderr]

You might also look at megashift its a transmission controller that works with megasquirt but can be run as a standalone

[MattyM]

http://www.msgpio.co...<br /> <br /> Looks pretty sweet! Ill do some reading!

[vmaxx]

I just hate when it upshifts to 3rd rapidly after giving 60% throttle in 1st then easing off abruptly. I'd rather leave it in D and not fiddle with the gearstick.

MB has their gearboxes programmed to hold the gear in that scenario. That's my only gripe about the brain of this gearbox, everything else is excellent.