So, I'm putting my old Accord back on the road, getting it ready for my youngest daughter. It's been sitting a couple years after loosing the clutch. I have to admit, I didn't realize I had neglected it as much as I had while out of work. Besides the clutch, it needed a CV joint, a front upper control arm, exhaust manifold pipe, master cylinder, brakes on the rear and all the wheels pulled to clean up corrosion and leaking wheels. AND, frigging mice got in and made a stinking mess of the trunk. Anyway, it's nickle and diming me to death and after getting it emissions passed and plated I was on the way home when I got the P1259 code. Reading up it seemed the usual culprit is the screen on the VTEC solenoid valve so I ordered new gaskets (screen) and also flushed the new 10-40 synt oil, replaced it with the "proper" weight 05-30 and tested both the sol and oil pres. switch which according to specs is all good. Another test run and at 4500 RPM she falls flat on her face and serves up another P1259 code. I figure the sol is getting weak but want to try adding another wire to limit voltage drop just to see what happens before popping another $160 for the valve and solenoid.. Does anyone know what pin on the PCM it comes from?

 

What year Accord? 4 cylinder?

 

http://engine-codes.com/p1259_honda.html

This gives a good description of what's happening. Like tech8 said, you have limited information so it's hard to find something more specific for you.

Looks like it would be your Oil Pressure Switch. I would assume that, as most Honda Accords did not come with VTEC Solenoids which is why Accord drivers don't usually get the VTEC Kick. (Correct me if I am wrong)

 

The VTEC only has the one wire feeding it, and i am trying to remember whether or not it is a full 12V. For soem reason I am thinking it is not a full 12V and that if you give it a full 12V youll fry it. But again, I am just thinking out loud. Im sure it is out there somewhere.

Have you pulled VTEC off...replaced the screen/gasket...and give it a good spray with cab cleaner? Perhaps the solenoid is gummed up.

 

DTC P1259: A problem in the VTEC Oil Pressure Switch circuit or VTEC Solenoid Valve circuit.

If it is a 6th generation Accord (98-02):

For both 4 and 6 cylinder:

• The VTEC Solenoid Valve wire is a Grn/Yel wire at terminal number 12 of the ECM/PCM Connector B (25P). Drives VTEC Solenoid Valve. With engine at low rpm: 0V. With engine at high rpm: battery voltage.

• The VTEC pressure switch signal wire is a Blu/Blk at terminal number 10 of the ECM/PCM Connector C (31P). Detects the VTEC pressure switch signal. With engine running at low speed: 0V. With engine at high engine speed (vehicle running): battery voltage.

 

Thanks All for your input...
Tech8, thank you for the info. Sounds like it would be prudent to put a volt meter on each line while driving to see what I have. Would revving it above 4500rpm in neutral engage the sol? At 170k miles that solenoid or switch could be going bad. Inside of the engine is clean as a whistle as was the valve and screen.

Car is VTEC 98 Accord Coupe 4cyl