What could cause a p1259 vtec dtc to be thrown at idle without going near 6000 rpms. I can sit in the car and delete the coad with my coad reader turn the car off start it back up and the code is immediately thrown at idle after about 2 seconds. What can cause it to do this?? the solenoid or pressure sensor??

 

 

It sounds like the pressure switch. Is there plenty of oil in the engine? I highly doubt the solenoid is stuck open as the car would idle like crap if at all . Perhaps you have a loose connection ? Those are the most likely causes. Good luck.

 

Actually it has had a crappy idle as of late. I think it may be time for a new vtec solenoid. Hopefully its not the oil pump.

 

:yikes3:

 

^ Thanks for your input.

 

lol, free bump

 

Here's your F'in input JK

The VTEC oil pressure switch is a normally closed switch. The ECM sends a voltage to the switch and expects the voltage to go through the switch to ground. If the ECM reads a voltage on that circuit when the VTEC system should not be operating, it will turn on the "check engine" light and set a code. This code will be a P1259 on a vehicle with OBD-II.

When the ECM energizes the VTEC solenoid valve to turn on the VTEC system, the ECM expects the VTEC oil pressure switch to open and see the voltage on the circuit. If there is a delay with oil pressure opening the switch, the ECM will set a trouble code and may limit fuel delivery, causing a driveability problem.

Reasons for no VTEC operation include low engine oil level, VTEC solenoid not opening or the screen behind it is restricted, an engine that has low oil pressure, or an oil pressure leak to the rocker arm assembly. In some cases, when engine work is performed, a missing or damaged O-ring can cause incorrect oil pressure to the VTEC system.

When diagnosing a trouble code P1259, always look at freeze-frame data. This data will tell you if the code is set at high or low engine rpm. If the code is set below 4,000 to 6,000 rpm (depending on the engine), check the oil pressure switch circuit for a faulty switch/connection or poor ground. When the code sets during VTEC operation, check for an oil pressure or mechanical problem with the VTEC system.

 

^ Thanks but I knew most of that. I am fearing a poor and failing oil pump is the issue. I am going to change back to a higher viscosity oil and check the pressure, if pressure is significant then I am going to test the assemble. Thanks to repiv aka xviper for his input on this.

 

If the 1259 is stored at idle it's not a oil pressure issue.

The oil pressure switch circuit is cause, since it's in a RPM range under VTEC operation the problem is electrical. Your e-manage and the splices can cause this.