Hondata

2004 Acura RSX Type-S
JRSC 5lbs.
70mm Throttle Body
Stock K20a2
Hondata Kpro

I reset the ecm. Test drove it and accelerated past 4000 rpms, check engine light comes on. P1259 Vtec System Malfunction. I have continuity at the vtec pressure switch. I have battery voltage at terminal 1 of the vtec pressure switch. I measured voltage at terminal 1 and 2 at the vtec pressure switch and its perfect. I checked resistance at terminal 1 and 2 at the vtec solenoid valve, calls for 14-30 ohms and I have 19.2 ohms. I removed the vtec pressure switch and applied an oil pressure gauge, it tells me to hold the rpm in between 1000-2000 and I have less than 7 psi, which is good. Next is checking the solenoid. I applied battery voltage and ground to the solenoid valve, held the rpms at 3000 and activated the solenoid and oil pressure is 64 psi. Battery terminals still connected to the solenoid, held the rpm at 4000 and I have battery voltage at B9 and body ground. Next I checked continuity at terminal B15 and body ground and I do not have continuity which it says I shouldn't. I connected the solenoid valve terminal 2 to body ground and checked continuity at B15 and body ground and I have continuity. The next step is that its telling me to update the ecm or substitute it with a known good pcm. Here's the questions, will it be ok to substitute my old ecm for the kpro to see if the light comes back on to check if the kpro is faulty? I don't wanna damage my engine or anything in that sort of nature. Help would be really appreciated.

All information came from Alldata.

It you have non-stock injectors I wouldn't use the stock ECU.

There are two conditions which can cause the error - the pressure switch off when using the low cam, or the pressure switch on when using the high cam. If at idle VTP is off then the problem is probably a shorted sensor; if the VTP is on when in VTEC it could be wiring or something mechanical with the sensor.

The simple solution might be to disable the VTEC pressure switch. It doesn't do anything useful, and is not present in non-US vehicles.

What is the serial number of hte K-Pro board inside the ECU and what is the serial number on the side of hte ECU case?

On the side of the ecu it says:

37820-PRB-305
2054-101106

The pin out case on the inside says:

37820-PRB-305
2054-101106-0K12

The hondata card says:

K-Pro
10459

I cleared all codes last night while at operating temperature and I did "ALOT" of WOT pulls and no vtec system malfunction codes popped up. Could it be an intermittent pressure switch? But I have continuity at the pressure switch. I put a new upstream oxygen sensor in today because it threw a P0134 code which is cleared now.

Yeah I have non-stock injectors RC 440's.

Have you disabled vtec pressure?

I will disable the vtec pressure switch tomorrow morning and repost. Visiting a relative in the hospital. Does the vtec switch have anything to do with the engaging part of it? Will I lose my crossover when I disable it?

Vtec pressure switch is disabled and I just got back from a test drive and the light didn't come back on after womping on it several times.