Daughter board communication error ...

[Jocker_666]

Hi there,

Sorry for a new topic but its a bit odd one and I didn't found anything like it here tbh.

I have an issue with my 2004 Civic Type R (Euro ver.). I'm getting a check engine error code - Daughter board communication error (battery voltage low when cranking).

I've checked and cleaned all earth's and got a new battery (380A crank) as car was sitting up for a few months. Battery is in OEM location. My car has AEM CAI, TODA Racing manifold and Supersprint exhaust (from manifold to back). Car is mapped on a Hondata KPro.

I've checked voltage with multimeter as per other threads that I've seen here. Voltage on the ECU (checked pin A2 and A4) is 10.9-11V.

Now here comes the tricky/funny bit that got me puzzled. That error code comes up even when I'm not going to start the car. I'm putting ignition on and after few seconds (approx 5-7) check engine light comes on. It shouldn't really as error code is in relation to cranking voltage so how come error code when there was no cranking??? Voltage on ECU when not cranking is 12.7V btw.

Now here is another thing that got me to write this topic as I just cant explain this to me at all and got me totally lost. I've plugged the ECU to my laptop, laptop was off. Tried to start the car and got same error code and same situation without starting. After that I've switched the laptop on with ECU plugged in but didnt start KManager and tried to start the car and it started and guess what? No error code at all! Car was running fine with no problems. Unplugged the ECU from laptop and no problem but as soon as I've started the car again error code appeared.

It looks to me like the daughter board is not getting enough voltage via the main board and when plugged via USB port it some kind gets that power that's needed. I know that I might be totally wrong but that's how it looks to me. I'm an electrician so I know a bit or two :).

Please help me guys as I'm planing a long Euro trip and need the car to be in proper working order before leaving... I've tried everything and every possible solution that I've found here but nothing helps... Never got a problem like that before with my car and I have it since 7 or 8 years now

Thanks in advance :)!

[Spunkster]

Have you tried the ECU in a different vehicle?

[josaya]

This is actually similar to my issue in the other thread. I've been checking precrank and crank voltages (12v+ and 10v+). PRA ecu as well! Could it be an issue with the PRA ecus?

Out of curiosity, did this start happening after kpro updated their software in April/May? I see another that's about the same and it coincides with yours and mine https://www.hondata.com/forum/viewtopic ... 12&t=20276 and the update

[Jocker_666]

Out of curiosity, did this start happening after kpro updated their software in April/May?

My car was sitting up for a good while so I don't think so. I've updated KManager week or two ago.

Have you tried the ECU in a different vehicle?

Didn't tried it yet but will do that to see if the ECU is the problem or something else. Thanks.

[Jocker_666]

I've tried today something different just to check if my theory was correct as I didn't manage to find anyone to swap around ECU's. So what I did is a simple thing - I've plugged in a power bank to see if the ECU will show the same error code or not. Guess what? With the power bank plugged in there was no error code what so ever and once power bank was not plugged error code appeared. It didn't make any difference if car was only in ignition or started up. So the issue is more than likely in the ECU itself and to be precise in the daughter board or around it (maybe connectors to the main board). Looks like its lacking power and it takes it from an outside source like a laptop or power bank.

I've tried also to clear the security on the ECU and got an error - Clear Security failed. Tried to upload a map and got also an error - Upload failed. Tried to download map from the ECU and got an error - The binary image in this ECU is security protected, blank or corrupt, and cannot be downloaded.

Could all of the above mentioned errors have anything to do with the daughter board communication error? Had the same errors before the power bank experiment - just to make it clear.

[Spunkster]

This does not sound like an issue with the ECU or the K-Pro board, but the fact that the ECU is not getting high enough voltage when the K-Pro starts up to work correctly.

[josaya]

This does not sound like an issue with the ECU or the K-Pro board, but the fact that the ECU is not getting high enough voltage when the K-Pro starts up to work correctly.

Voltage on ECU when not cranking is 12.7V btw.

Both of us are having ECU voltages of over 12.5V when the error occurs... surely that is enough?

In old PC times, a dead capacitor would exhibit the same issues as what we're seeing. Charging the board long enough would still fire up the PC eventually, but never on first PC.

Some "possible" solutions after reading over 50 threads...
New Full-Sized Battery
Re-Grounded Car
Checked Every Connector / Grounding Point that had to do with the PCM/ECM
Tried reinstalling/updating software and different laptops.
Resoldering a bad connection with the daughter board to the motherboard ecu
Fuel relay replacement

[Jocker_666]

This does not sound like an issue with the ECU or the K-Pro board, but the fact that the ECU is not getting high enough voltage when the K-Pro starts up to work correctly.

Spunkster no offence to You and I really appreciate all the help I'm getting here but like josaya already mentioned voltage on ECU (between A2 and A4) measured with a multimeter is in proper order (12.7V when not cranking and 10.9-11V when cranking) so it has to be something else. Is there a way to check if the ECU is in proper working order? Also what about those error codes that I'm getting? Is that not a sign that there is something wrong with the ECU?

[Jocker_666]

I gave it a go again today to try and diagnose the problem. This time I've had a good look at the ECU itself and decided to take it apart and give it a good clean as the car was sitting up for a while. I disconnected the battery and took the ECU out of the car. Took the top cover out and decided that if there is an issue with the daughter board Ill start there and go from there. Unscrewed two screws that hold the daughter board and slowly took the daughter board out. I've cleaned the board with just a cotton ear buds all the way around (including pins that go into the main board). Done the same thing to the main board and then put the daughter board back on top of the main board and tightened the screws. Put the ECU back in the car and plugged the battery. Started the car up without no problem and guess what? NO error code what so ever :)! Plugged in the ECU to the laptop and no error codes also no problems with uploading the maps. It looks like there was some dirt or moisture somewhere around that was causing the problem but it is all gone now! Happy that the issue was taken care of and hopefully it will not come back any more :)!

josaya don't know if You tried to clean Your ECU but maybe give it a go and it will help as it surely helped me.

[josaya]

josaya don't know if You tried to clean Your ECU but maybe give it a go and it will help as it surely helped me.

Cheers for the heads up :D Will give it a go before ripping out all my wiring\cabling over the weekend.

[Jocker_666]

Cheers for the heads up :D Will give it a go before ripping out all my wiring\cabling over the weekend.

Fingers crossed it will help and You don't have to go to extremes :).

[josaya]

Unfortunately a new battery and a ecu clean didn't work.
I'll spam my own thread after this :)

[Jocker_666]

Unfortunately a new battery and a ecu clean didn't work.
I'll spam my own thread after this :)

Sorry to hear that josaya. Good luck and fingers crossed You'll get it sorted out!