A new/peculiar Daughter Board Comm Error...

[BrianJewell1988]

I had the misfortune of Hydrolocking my K20Z1 in my 05 Type S. As I dont plan on doing much with the csr sans bolt ons and tuning (Nissans have me bankrupt as is), I swapped in a DC5R K20A.

The swap went well, everything works as it should, popped the RBC Mani back on and the 70mm TB. Got cruise control back and functioning.

Here's my issue. I wanted to build a new map off of the Hondata supplied K20A-itr base map. When I do this, and ONLY on that map, I get the Daughter Board Communication error, the second I clear the DTC for it, even with the car running and supplying 14.4v...it comes back within about 3 seconds.

Any of my old maps for my K20Z1, the error does not appear.

Cranking voltage drops to about 12.4 at minimum (brand new bat, and a large one at that. 920cca)

The only thing I can think of is perhaps the new K20A map is looking at/testing an 02 sensor or something else that may be causing a V-drop or maybe something os shorted that is only referenced in the ITR map?

Any insight would be greatly appreciated,

[Spunkster]

Where are you getting the calibration that has the issue?

[BrianJewell1988]

Sorry for the lack of clarity on that.

The Cal with this problem is the Hondata supplied basemap titled." K20a itr" ...then states 310cc's, Toda header, etc

[Spunkster]

Post the calibration as you are using it.

[BrianJewell1988]

The Cal with "no issues" is this one.....

k20a old motor disabled VTec oil psi switch.kal

(164.25 KiB) Downloaded 111 times

The basemap, unedited Cal that I'm having the continuous DaughterBoard comm error and accompanying DTC/CEL is...

k20a-itr basemap.kal

(163.1 KiB) Downloaded 102 times

[BrianJewell1988]

Post the calibration as you are using it.

The Cal with "no issues" is this one.....

k20a old motor disabled VTec oil psi switch.kal


The basemap, unedited Cal that I'm having the continuous DaughterBoard comm error and accompanying DTC/CEL is...


k20a-itr basemap.kal

[BrianJewell1988]

Has anyone experienced an issue with only 1 map but not the other before?

[Spunkster]

No, it should not be a calibration related issue. You need to use a multimeter and measure the voltage at the ECU when cranking with the different calibrations.

[BrianJewell1988]

Voltage going into the ECU, (using a T pin and multimeter for reference)

Original/"no issue" .kal - 11.7v was lowest I saw

K20a-itr basemap "comm issue .kal - 11.55v was the lowest I saw, so it was a bit lower.

[Spunkster]

My guess is that you have an issue related to wiring and or more than likely related to equipment or oxygen sensors.

[BrianJewell1988]

With how you and the database explains that DTC is triggered in the 1st place, that has to be it. Must be looking for something like that on initialization. Thanks for the help. I'll update with result/fix.