4.2 RAV4 D4-D SCV Valves:
Ok, here goes with the details I know about the SCV valves and their replacement on the 4.2 RAV4 D4-D. Or at least this is how I did it, maybe not the best way but it worked for me! I have yet to look on the official Toyota technical website to see if there are any better instructions in their service manual.
The symptoms were fairly similar to others who have posted on the forum, ie: loss of power, especially at the top end of the rev range above 3000rpm. Sometimes it would be fairly intermittent and at others the RAV could not get out of its own way!! There was no MIL to start with but that soon changed..... It would come on and off but then it came on and stayed on. The DTC stored was P0627 relating mainly (as it says there could be something else causing the problem) to the SCV valves as below:
I also checked the electrical side of the valves, but mine were both in spec. You can check for continuity between the valves and the engine block and resistance across the valves themselves:
And if required the following shows the wiring between the SCV valves and the Engine ECU:
New valves were purchased from Kingo [aka Parts-King on the Forum] for £194.16 inc. VAT & p&p. Part # is: 04221-27011 and is described as: "Pump Kit, Supply". Ace service from him!
Firstly I undid the two nuts holding the coolant tank in place. Then carefully lifted the tank off the studs (and the locating spigot under the tank) and moved it to the left. I managed to fix the right hand hole onto the left hand stud (if that makes sense!) and could then hold it in place with a nut put on finger tight. Just kept it nicely out the way although you could achieve the same thig using a cable tie I guess. Then I removed the air intake pipe running between the front of the intercooler and the throttle body. This is the main, large diameter black pipe in the photo below (the location of the SCV valves is highlighted by the red circle):
Once this is done you should have something which looks like this:
I also removed the nut holding the wiring loom trunking in place (in the green circle) to gain better access. The red circle is where the SCV valves are.
To identify between the two valves, the front one is redish brown and is SCV 1, and the rearmost one is green and is SCV2. I did one valve at a time to ensure I didn't mix them up and started with the rear most one (closest to the engine block) as this is the most difficult to do because of the limited access. Always better to start with the hard one as when you're bored and tired the second one seems easier!
After undoing the electrical connectors to each valve I then removed the cap/allen head screws holding the valves themselves in place. I needed to use a small screwdriver between the flange and the fuel pump to carefully prise the valve out of it's housing as it was quite tight. Once removed you can push the new one into place. Due to the limited access I could not push the valve fully home so used the fixing screws by tightening each screw a few turns each, alternating between each one, to make sure that it went in square. The other valve was changed in the same way but was a little easier due to the better access.
The following photo shows the new rear (green) valve in place and the old front (red) one removed before fitting the new one:
Once both new valves were in place I wiped up as much of the spilt diesel as I could (not much came out when the valves were removed really), just helps to check for leaks if the area you're checking is already dry. Then I replaced all the components I'd taken off.
Not sure if it helped but I pressed the priming button on top of the fuel filter head until I felt resistance to make sure the fuel system was full.
That's it! The engine started almost immediately and ran fine. On the second ignition cycle the MIL went out and has been out since (keeping my fingers crossed here!).
I guess it will be a good idea to get the fault codes cleared at some point as the original DTC will still be present as a historic code. Always good practice to clear the fault codes once you have fixed the problem.
The following photo shows the old valves. The new ones didn't look any different to be honest, except cleaner!
All in it took about 1hour from start to finish.
Hope this helps someone else! :)