Hondata

eg/k20z3, I have the following error: Daughter board communication When cranking voltage low, ground perfect, new battery oem location. charging 14v, drops to 12v and misfire in the blink of an eye, and becomes perfect to 14v

Is the battery in the OEM location for an EG, or OEM for a K20?

Spunkster wrote:Is the battery in the OEM location for an EG, or OEM for a K20?

OEM location for an EG

EGK2082 wrote:drops to 12v and misfire in the blink of an eye, and becomes perfect to 14v

With the engine running, or when cranking?

What does the voltage drop to when cranking? Can you make a datalog?

Have you measured the voltage with a multimeter at the ECU when you are cranking and get this error?

Hondata wrote:

EGK2082 wrote:drops to 12v and misfire in the blink of an eye, and becomes perfect to 14v

With the engine running, or when cranking?

What does the voltage drop to when cranking? Can you make a datalog?

happens with the engine running
I'll make a datalog

Best to use a multimeter on the ECU pins (A2 & A4) when cranking. Be very careful not to short anything out.

I've had this same error/problem recently. The ECU would throw the code immediately after the motor started. I had a friend check over everything and I had a bad ground at the battery. We fixed the ground and the problem hasn't returned. I would start there and get a second opinion on it from someone good with wiring to make sure that's not the problem.

Problem solved, one of the ground wire, had not had good ground, had painting.

Glad it is fixed and thanks for posting the solution.

Hondata wrote:Glad it is fixed and thanks for posting the solution.

Thank you for helping me.

I had the same issue, I replaced the ground on the battery never had any problems after that.
Also , if you turn the key to on , wait for the fuel pump to prime and the kpro clicks, then turn the engine,
this trick helps to get less check engine lights while you figure what is caussing it