I did the procedure in the attached image to test vtec. I got 3.7ohms so I need to replace the "spool valve." Does that mean I need to replace the entire unit or the solenoid that sits on top? Basically do I need part #13 or #9 in the second picture? I tested the single wire coming off of the solenoid (part #13) with the multimeter, but the troubleshooting guide makes it seems like I need the spool valve assembly and not the solenoid. Unless that was just made for a dealer who replaces the entire unit instead of just the solenoid? I also connected the solenoid to 12v+ and it clicks, but the testing says it is not in spec so replacing something is on the to-do list here.

 

Bump

 

You basically need all but the pressure switch. But honesty you might as well get that too. I'd just get a used whole assembly on eBay or somewhere.

 

First you should ignore me this is coming from experience troubleshooting sprinkler valves and other electric circuits, ultimately you should listen to an expert.

Now my .02
The only circuit that connects to the p1 connector, that is failing the resistance check is the solenoid. Solenoids are an electomagnet that generally pull a piston. When a solenoid is activated current passes through the coil and it heats up. That heat slowly burns off the insulation of the wire and causes the coil to begin to short across itself. When that happens it effectively shortens the coil: a)decreasing resistance b)decreasing the strength of the electromagnet c)increasing the amount of current and heat produced in turn increasing the rate of decay.

If this sounds like your issue and you've done the other troubleshooting steps likely your issue is the solenoid itself.

If you tested the valve (step on right side of the attached page) and it functions as described I don't get why you'd replace it. In fact I think replacing it with unknown used parts introduces additional failure points.

If it were me I'd recheck resistance and replace the solenoid assembly by itself with new if you can since all solenoids wear out this way and you might as well buy a full life.

 

Try cleaning it out and using a new screen/filter on the the top part of the solenoid if it still fails replace the top portion or just find another used one.

 

Part #13 is what you need as long as the rest of the spool valve is in working condition.

What prompted you to check the spool valve in the first place? Is VTEC not engaging?