Vida CEM swapping

[NFedor]

I am pleased to announce I have disabled slip lockup. The slip lockup maps now become the default full lockup maps. There is only slight slip lockup during engaging of the torque converter and possibly during shifting, which is normal and required.

how do I change the final gear ratio?

[vtl]

I am pleased to announce I have disabled slip lockup. The slip lockup maps now become the default full lockup maps. There is only slight slip lockup during engaging of the torque converter and possibly during shifting, which is normal and required.

How does it feel in practice?

[dikidera]

I am pleased to announce I have disabled slip lockup. The slip lockup maps now become the default full lockup maps. There is only slight slip lockup during engaging of the torque converter and possibly during shifting, which is normal and required.

How does it feel in practice?

Well the lack of slipping lockup feels great, I am still getting accustomed to it not kicking in. My transmission was never in a good condition either way, so whenever my TC engages/fully locks there is a small to medium kick to it. Now it engages at lower speeds(what were once the slip lockup speeds so between 45-60kmh) which is weird for me, but we will see if there are any downsides.

[vtl]

I am pleased to announce I have disabled slip lockup. The slip lockup maps now become the default full lockup maps. There is only slight slip lockup during engaging of the torque converter and possibly during shifting, which is normal and required.

How does it feel in practice?

Well the lack of slipping lockup feels great, I am still getting accustomed to it not kicking in. My transmission was never in a good condition either way, so whenever my TC engages/fully locks there is a small to medium kick to it. Now it engages at lower speeds(what were once the slip lockup speeds so between 45-60kmh) which is weird for me, but we will see if there are any downsides.

How do you update TCM? On the bench or over CAN? My transmission was fully rebuilt about 3 years ago, and it works great, but I feel the controlled slip was never a good idea. I also have a spare TCM, just in case

[nikemen]

Hello there!
I've got the printed board (https://www.pcbway.com/project/sharepro ... 037d5.html) to crack the CEM PIN of my C30 and I soldered the Teensy and the Bosch transceivers, but it doesn't work. I got no communication with the car's bus, regardless of the key position. Basically, I get the same respnse in the console whether the cable is connected to the car's OBD or not.
When I compare the plan posted on volvo-cem-cracker's Github to the board I got, I see my board hasn't any resistor. I get R3 and R4 are not needed when cracking via OBD, but the board has no place either for R1 and R2. I think that could be the source of the problem, but I am not sure.
Also, the Bosch CF160 transceivers don't have numbered pins or a dot to signal pin 1, so I could have soldered them wrongly... but nothing smoked while connecting them.
Can someone guide me in the right direction? Did someone make it work with the PCB I got?
Thanks in advance!

Show pictures?

Here they are. The setup is not good looking: due to the chip shortage when I bought the components, I got a Teensy 4.1 instead of a 4.0.

[dikidera]

How does it feel in practice?

Well the lack of slipping lockup feels great, I am still getting accustomed to it not kicking in. My transmission was never in a good condition either way, so whenever my TC engages/fully locks there is a small to medium kick to it. Now it engages at lower speeds(what were once the slip lockup speeds so between 45-60kmh) which is weird for me, but we will see if there are any downsides.

How do you update TCM? On the bench or over CAN? My transmission was fully rebuilt about 3 years ago, and it works great, but I feel the controlled slip was never a good idea. I also have a spare TCM, just in case

Both. On the bench and on car. Checksum is easily replaced by the TCM itself(otherwise it enters limp home mode), but I had to modify a special memory address to force it.

[vtl]

Here they are. The setup is not good looking: due to the chip shortage when I bought the components, I got a Teensy 4.1 instead of a 4.0.

No common ground between OBD connector and Teensy? The original schematic has it:

schematic.png (95.47 KiB) Viewed 238 times

[vtl]

Both. On the bench and on car. Checksum is easily replaced by the TCM itself(otherwise it enters limp home mode), but I had to modify a special memory address to force it.

Do you have the instructions buried in the hundreds of pages here or is it something to be written yet?

[dikidera]

Both. On the bench and on car. Checksum is easily replaced by the TCM itself(otherwise it enters limp home mode), but I had to modify a special memory address to force it.

Do you have the instructions buried in the hundreds of pages here or is it something to be written yet?

Kind of. Each firmware for TCM changes the memory address locations, so what is one memory address for me, is quite different to you. And also depends if that particular code path exists for you. If it doesn't the checksum will need to manually searched in the EEPROM and overwritten.

To find the relevant memory address you need to see param A5 A7 to which memory address it corresponds, and from there see all xrefs to it



Hopefully finding the above code. There might be a more elegant way to trick TCM into updating it without fully knowing the memory address, but so far I can't say which method it is.

Method 2

Search entire EEPROM(it's very big) for the checksum (A5 A6 is the expected checksum) and if you can write to the EEPROM, update it that way with the value of Calculated Checksum. Then simply use VIDA to read and erase DTC(AE11 then AF11)

[vtl]

While reading the Bosch CF160 datasheet, I noticed it has a difference with SN65HVD230 with regard to slope control in latter:

Rs (pin 8) - SN65HVD230 and SN65HVD231: Mode select pin: strong pull down to GND = high speed mode, strong
pull up to VCC = low power mode, 10kΩ to 100kΩ pull down to GND = slope control mode

10.4.1 High-Speed Mode
The high-speed mode can be selected by applying a logic low to the RS pin (pin 8). The high-speed mode of
operation is commonly employed in industrial applications. High-speed allows the output to switch as fast as
possible with no internal limitation on the output rise and fall slopes. If the high speed transitions are a concern
for emissions performance slope control mode can be used.

The cracker uses a 10kOhm resistor, thus the chip is in a slope control mode. That affects latency a bit. Those 20% harder to crack P2 CEMs may perhaps benefit from having the pin 8 connected directly to the ground. My cracker setup is still in one of the boxes in the basement after moving to a new home, can't test it out if the latency detection is better/worse/same.