2003 honda accord dx has a cel p2646 what cause this light to come on. is it the oil pressure switch bad or spool valve.

you replaced the solenoid but the code refers to the actuator A bank 1--performance problem or actuator stuck off====causes wiring---rocker arm actuator
have it professionally checked and if faulty replaced , then the code will be cancelled

code p 2646 refers to rocker arm actuator A bank 1---performance problem or actuator stuck off=== causes wiring--- rocker arm actuator
discuss the problem with a service dealer shop or an accredited service shop that has experience on your make of vehicle
with rocker arm problems , to stop rotation it may be bottoming out on a valve spring and not letting the cam shaft turn .
talk with a shop for a proper diagnosis and quote

Not related, first is a transmission output speed sensor code, check the connector, it's probably the reason you have slamming when it s cold.
second code is for low vtec oil pressure, usually caused by low engine oil or dirty/wrong viscosity oil being used.

Low oil or wrong oil will cause issues with the variable valve timing solenoid as it is a hydrolic valve that used the oil to work when commanded.

p2646 vtec oil pressure switch circuit low voltage - check wiring or change sensor

This is an error code related to VTEC related Honda engines. I am sending you a little reading on that error code.. Best of Luck..


The Check Engine Light (CEL) is on. Trouble code P1259. Tests/Procedures: 1. Locate the Variable Timing/Lift Control (VTEC) pressure switch, on the back of the cylinder block, by the oil filter.

2. The VTEC oil switch is normally closed and grounds the reference voltage from the Engine Control Module (ECM) on the Blue/Black (BLU/BLK) wire.

3. At approximately 4000 RPM, and when driving the vehicle, the VTEC system should turn on. To turn the system on, the ECM energizes the VTEC Solenoid valve and it allows oil pressure into the intake valve rocker arms, the oil pressure opens the VTEC oil pressure switch so the ECM can verify that VTEC did turn on correctly.

4. The code will set below 4000 RPM if the reference voltage is not grounded. The code will set above 4000 RPM if the VTEC oil switch does not open.

5. If the code sets at 4000 RPM or higher, the problem can be a low oil level or pressure, or a malfunction in the VTEC assembly. Potential Causes: Low Engine Oil
Plugged Oil Passage
Insufficient Oil Pressure
Plugged Oil Screen
Insufficient Oil Volume
Malfunctioning VTEC Oil Pressure Switch
Defective VTEC Solenoid
Tech Tips: When the P1259 code sets at 4,000 RPM or higher, always verify that the engine oil level is full. Also, if there is an oil pressure or volume problem, always verify that the oil pan is not pushed up and is too close to the oil pickup tube, causing an oil volume problem. Be very careful when supporting the engine with the oil pan.

P1259 is the code for the VTEC pressure switch.

1. Check your oil level first, if oil level is low the code will come on. Add oil and reset the light.
2.you might have a bad Vtec oil pressure switch, try replacing it.

try this link, i tried to list them but their were to many P2646 VTEC Oil Pressure Switch Circuit Low Voltage

*http://www.honda-tech.com/showthread.php?t=978933*

10 psi minimum at idle and 50psi at 3000 rpm are needed for the light to be off. If you have this check for a bad ground wire and reset the CEL.
Good luck...i hope this helps

the actuator is faulty and you could clean it, reset ECU error and check again