p2647 rocker arm control solenoid high voltage

[lethal804]

alright new here so don't know if its the right section working on a 2005 acura mdx with a code p2647 the car was in a accident the motor mount pushed into side of engine block so had to get a new block so far the customer has already replaced the pcm ive went through all the ground wires from g101 there all good checked the wires coming of the vtec solenoid and vtec oil pressure switch its good installed new spool valve assembly with the key on the wire from the oil pressure switch gets about 7 volts when unplugged from sensor my question is what else should I check before I tell this person they need a new pcm have another question could the head have gotten assembled wrong causing the rocker arm pin to stay in causing this code

[SuperTech]

How well does it run? If the rocker arms were locked together (as if VTEC is engaged), it would not run so smooth at idle. And you've have some pretty wacky fuel trim numbers.

[lethal804]

it runs fine has power idles good sometimes in the morning It will throw a misfire code for all cylinders had me leaning toward the ckp and cmp sensor but I wanted to fix the p2647 first and then check for fuel starvation and everything else that would cause a miss when I check it with the scanner I can see the vtpsw turning of and on so I know its working my question is what tells the pcm that the rocker arm is locked together or stuck on

[SuperTech]

All the misfire codes will most likely be from the valve clearance needing adjustment.

As far as I remember, there is no feedback system to tell the PCM the rockers have locked. It is just assumed that it works when the solenoid is commanded on.

[lethal804]

i was leaning towards the valves also but when the block was cracked the whole engine was assembled at the machine shop and that was less than 5k ago ii mean I know they can make mistakes.... so I guess my question is with the vtpsw unplugged does it suppose to get voltage with key on and if it were you after tracing all the wires would you go ahead and tell the person that the pcm that he replaced with a used one is also bad

[SuperTech]

I honestly don't know off the top of my head what is normal voltage for that circuit. And as I said in another thread, looking up part numbers, or in this case diagnosis procedures, is more time than I want to put in here on this forum.

If the procedures you have have been followed to the letter, and you're at the "substitute known good PCM" stage, then you're best off sending it to the dealer. Since even if the PCM gets replaced, the dealer has to program it for the Immobilizer keys.

[lethal804]

still working on this problem winter caught me so i havent been able to do anything just a update replaced pcm and all grounds are good i think my problem may be internal maybe a bad rocker arm piston spring or something along those lines will update as soon as i have time