Difference between 06+ Si and 02-04 DC5 ecu

signalpuke · Post by **signalpuke** » Thu Dec 21, 2006 3:25 pm

Hondata, I am trying to broden my knowledge of how the factory ecu's work. Of most interest to me is the protocal's used and what functions are processed through the multiplexer. Any links to this information would be greatly appreciated.

I have been told that to run K-Pro (for say a K20A2 swap) in an 06+ Si two ecus would need to be used. The reason for this is because the the guage cluster will not function without the factory ecu (vss). Is this still the case if the user used an 02-04 AP2/aftermarket guage cluster, and used a throttle cable. All sensors for the engine would match the ecu, and the appropriate VSS would feed the cluster. Any insight to this particular situation is appreciated.

Post by **Hondata** » Thu Dec 21, 2006 7:35 pm

There is far too much to cover here. The RSX ECU runs the water temp, charge light via the multiplex. The Civic Si runs the whole dash via multiplex. It doesn't really matter what the exact protocol is except that they are vastly different, and therefore are not interchangeable.

To use a RSX ECU in an 06 Si you would need to swap over the engine harness, body harness, dash harness, dash & cluster, throttle body, throttle pedal assembly, plus some other functions will never work, like the AC, cruise control. Also the throttle pedal is a plastic device which sits on the floor and the Si has not got any firewall mounts for the RSX style pedal. Anyhow, this is why we don't recommended using the RSX ECU (but it has been done for race cars).

02-04 AP2?

signalpuke · Post by **signalpuke** » Fri Dec 22, 2006 12:21 pm

Thank you for your quick reply, that is what i thought about the multipexer, just wanted to make sure.
Is Honda keeping this type of management system (CAN?) in future applications across all platforms?

Post by **Hondata** » Fri Dec 22, 2006 1:53 pm

CAN is required by the EPA for all 2008 MY vehicles, so all future Hondas will use CAN.

signalpuke · Post by **signalpuke** » Fri Dec 22, 2006 2:41 pm

How much does the 06SI and the Honda Fit have in common regarding the engine swap question? The Fit has the Drive by Wire, is this where the similarities end?

Post by **Hondata** » Sat Dec 23, 2006 11:23 am

They are similar.

signalpuke · Post by **signalpuke** » Sat May 19, 2007 6:30 pm

Hondata wrote:They are similar.

Is that to say the Fit and 06si ECU and dash wiring are close enough that swapping the K20Z3 would be feasible? Are the CPU's different?

Post by **Hondata** » Mon May 21, 2007 9:56 am

The way to find out would be to compare wiring diagrams for each vehicle, but I doubt that they are going to be the same.

signalpuke · Post by **signalpuke** » Sat May 26, 2007 6:35 pm

A PNP wouldn't be that difficult if it is only for one ECU. This is just theory until I can actually get my hands on a copy of the wiring diagrams, but if the ECU's between the Fit and the 06Si share enough componetry then swapping the K20Z3 into the Fit shouldn't be as difficult as the K20A. Retain the DBW, retain the dash, add your reflash, and it is good to go. Hasport sells the mounts now, but everyone is scratching their heads about how to keep the car "functional" lol.