NefMoto

Long time lurker, first time caller.

Full disclosure ECU's are not my "lane" so I'm a noob when it comes to them and I stay in my own which is clusters (and in these cases, need CANBus traffic to them) but have an ECU related issue. Some B5 S4's and 8N TT's have xxx920xxx clusters and even have the CANBus wires factory installed on S4's but for Powertrain CAN (adaption channel 60) the value is set to 0 and tacho is run off analog wave signal and there's no CAN messages to cluster. Changing adaption channel to 1025/1027 causes tacho to stop working and oil pressure warnings and of course still doesn't enable the traffic from the ECU. On S4's I've been getting around this by having a tuner just flash A box ECU's (no CANBus to cluster) to MBox ones (CANBus to clusters) with Bosch MAF tables and setting cluster adaption channel to 1025/1027. Doing this resolves all the issues and cluster works as I need without any further hardware changes to ECU or wiring.

After looking through the FR and searching here, it seems there are 6 CAN send/receive related bytes in the flash but not sure which of those exactly would need changed and to what value (assuming nothing else is being changed on the car and only enabling CAN messages to Kombi). And from what I can tell nothing needs changed in EEPROM but could be incorrect in that.

What I've found on here for a ME7.1 addresses but not sure what values to add/subtract from each or if all 6 even need changed:
cw_can_s_0_a 0x12C80
cw_can_s_1_a 0x12C82
cw_can_r_0_a 0x12C7A
cw_can_r_1_a 0x12C7C
cw_can_r_2_a 0x12C7E
cw_can_c        0x10191

Thanks for any insight.

https://s4wiki.com/wiki/Tuning#Missing_Message_from_Instrument_Cluster

Yeah saw that but it's essentially backwards from what I need unfortunately. Not trying to stop send message to cluster, trying to enable it on Bosch cars.

So compare CW_CAN_S between M box and A box and modify.