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When driving the vehicle with the rpm high enough for VTEC operation, the engine control module (ECM) operates the variable valve timing solenoid to open the solenoid and allow oil pressure to be applied to the pistons in the intake rocker arms. This action causes the outer rocker arms to be pinned to the middle rocker arm and now the three rocker arms operate as a unit, using the high-lift camshaft lobe for improved high-end power. When the engine rpm drops below VTEC operation, the VTEC solenoid is not energized and hydraulic oil pressure is turned off. This allows the return spring to return the pistons to their rest position and lets the rocker arms operate independently again. The VTEC transition between low and high rpm is smooth and normally not felt by the driver.

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.
 

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Discussion Starter · #3 ·
When driving the vehicle with the rpm high enough for VTEC operation, the engine control module (ECM) operates the variable valve timing solenoid to open the solenoid and allow oil pressure to be applied to the pistons in the intake rocker arms. This action causes the outer rocker arms to be pinned to the middle rocker arm and now the three rocker arms operate as a unit, using the high-lift camshaft lobe for improved high-end power. When the engine rpm drops below VTEC operation, the VTEC solenoid is not energized and hydraulic oil pressure is turned off. This allows the return spring to return the pistons to their rest position and lets the rocker arms operate independently again. The VTEC transition between low and high rpm is smooth and normally not felt by the driver.

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.
When driving the vehicle with the rpm high enough for VTEC operation, the engine control module (ECM) operates the variable valve timing solenoid to open the solenoid and allow oil pressure to be applied to the pistons in the intake rocker arms. This action causes the outer rocker arms to be pinned to the middle rocker arm and now the three rocker arms operate as a unit, using the high-lift camshaft lobe for improved high-end power. When the engine rpm drops below VTEC operation, the VTEC solenoid is not energized and hydraulic oil pressure is turned off. This allows the return spring to return the pistons to their rest position and lets the rocker arms operate independently again. The VTEC transition between low and high rpm is smooth and normally not felt by the driver.

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.
Ummm so it could be the vtech solenoid right?
 

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Yes, could be. Get your codes read. And welcome to the forum.

 

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Discussion Starter · #7 ·
Yes, could be. Get your codes read. And welcome to the forum.

Ohok thanks you.
 

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Yes, could be. Get your codes read. And welcome to the forum.

Ahhhh, thanks, as Paul Harvey would have said, now we have "The rest of the story."
 

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Who knows about the vtech solenoid on a 2007 honda pilot??
What's your Milage? Do you have an engine code? I ask these question because this is an eventual problem for older high millage Honda equiped with Variable Valve Timing (VVT). Do not do a half job by just replacing the solinoid. Replace the gaskets and screens between the solinoids and between the spool and engine. There is a set on both sides of the engine. One set is found as part of your oil filter housing, the other is up by the head on the drivers side. These gaskets are known to leak oil and the screen filters get plugged.
Are you inclined to DIY?
 
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