Hondata

After updating kmanager from version 3.1.6.0 to 3.2.4.0 I now get the "Daughter board communication error" if I start the engine with the laptop plugged in to the ECU with the USB cable. When I start with no laptop plugged in I get no error. I can then plug the laptop in and datalog with no problems.

I definately did not get the error with version 3.1.6.0 1 week ago. Nothing else has changed, I just download 3.2.4.0 this weekend to do a bit of tuning and and the error started occurring.

My battery is a few years old, but even fully charged I get the same error. I can't imagine that the laptop is drawing so much current through the USB cable to trigger the error!

Any ideas?

What is the battery voltage at the ECU when cranking when this error occurs?

I'll get the multimeter on it this weekend.

Just completed some tests. Between pin A2 and A4 at the ECU I get 10.5 to 11.0v when cranking, rising to 14.1v when the engine starts. But, I can't get the error to appear today, with or without the USB plugged into the laptop, so it can't be anything to do with the software upgrade.

The only thing I can think is that the compression tests I did before I went tuning last weekend had taken enough life out of the battery to reduce the cranking voltage, and the battery has sufficiently charged this week to prevent the error.

It's just a bit odd that the error only occurred when the laptop was plugged in when starting the engine, and would not appear if the laptop was unplugged when starting the engine.

I'll check the voltage again if the error re-occurs.