Turbo vacuum solenoid replacement?

krb · **Posted:** Sun Mar 17, 2024 5:07 am

Anyone know of options for the Mopar part number 4606226AC? EVERYWHERE I've checked for months on end they are back ordered or out of stock. I've been on the waiting list at IDParts for almost 2 years.

I've been in bypass mode and it seems to do OK but I hate having something "rigged" and the hissing noise for minutes after shutdown keeps reminding me...

Surely somebody has found some other part or application that works? I'd try and snag one at the junk yard but who knows when another CRD Liberty will show up around here, and even then it may or may not be a functional unit.

Any ideas???

WWDiesel · **Posted:** Sun Mar 17, 2024 11:48 am

Found some listed on eBay, kinda pricey, but probably high due to availability.
https://www.ebay.com/sch/i.html?_from=R ... =0&_sop=15

If you Google the part number, a few Mopar web sites still show them as available, I would call to confirm availability before ordering. :google:

Also, several people have posted about parting out a Liberty diesel, so you may be able to snag a good used one.
Search on the FaceBook diesel jeep group: > https://www.facebook.com/groups/libertydiesels/

You can also just bypass the vacuum solenoid. Its only function is to hold the vacuum in the small vacuum chamber for the turbo vane controls.
With it bypassed, just allow the engine to idle for a 30 seconds or so to build up some vacuum.

See this picture to bypass the solenoid:

krb · **Posted:** Sun Mar 17, 2024 12:13 pm

Those ebay ones are about twice what is listed on various Mopar sites. Everywhere I've checked they are out of stock or back ordered.

Guess I'll just live with it as is til another shows up at Pull-apart.

Thanks,

WWDiesel · **Posted:** Sun Mar 17, 2024 12:46 pm

krb wrote:

Those ebay ones are about twice what is listed on various Mopar sites. Everywhere I've checked they are out of stock or back ordered.
Guess I'll just live with it as is til another shows up at Pull-apart.
Thanks,

Why not bypass it?

There are plenty of 12v vacuum solenoids available on Amazon for cheap. https://www.amazon.com/vacuum-solenoid- ... noid+valve
You may could rig one of them up to work until you get the correct part? Just be sure and get one that is normally closed. :wink:

It is just a simple open/closed valve. Power is applied to it (open) when you turn the key to the on position.

Titan Joe · **Joined:** Sat Aug 20, 2022 2:08 pm **Posts:** 17

Has anyone tried an evap valve off a European turbocharged car. Seems like one of those could possibly work especially if it had the same impedance. Maybe something like this: https://www.fcpeuro.com/products/volvo- ... gJtSvD_BwE (Pierburg 9470775). Snatch one at your local junk yard with the pig tail. Of course make sure this makes sense, I don't want you burning out something in the ECM. I'd make sure the coil resistence is pretty close to the oirginal (unless that's the issue you are having).

krb · **Posted:** Mon Mar 18, 2024 5:19 am

Hmmm, I'm not opposed to making something else work. But, if all it does is store vacuum for instant turbo at startup then I'll not go to the trouble. I always let the engine warm up anyway. And since I live at the end of a gravel drive at the end of a deadend road, warm up is never an issue.

Can I just plug all the exposed ends then and go on my merry way with no worries? The hissing noise after shutdown annoys me...

Cheers,

SJBrooks · **Joined:** Tue Mar 11, 2014 11:01 am **Posts:** 95

Resurrecting this old thread…

I recently drove through some standing water and some splashed up under the hood. While there was no immediate problem, upon next engine start I got a CEL with codes P0700 and P0403. Now, while it will crank/start/move, there’s zero engine power and no shifting beyond (I think) 4th gear.

Years ago, I experienced the same combined codes and the fix was a new 4606226AC turbo vacuum solenoid and adding a little bit of fluid in the transmission. Now, of course, there are zero new solenoids to be found. I opened the hood and let it all dry out for a day and blew out the solenoid electrical connectors and various other connections. I also did the bypass shortcut WW mentions above, but there was zero improvement. I haven’t yet checked the transmission fluid level.

Does anybody know where to get a new solenoid from, or am I going to have to use eBay? Are there any other suggestions anybody can make on causes/fixes for these two codes?

Many thanks in advance for the help!

Steve

WWDiesel · **Posted:** Tue Sep 29, 2026 12:48 pm

1.You can bypass the vacuum solenoid if necessary, the system will work without it until you can find a suitable substitute. See picture 1. with instructions below:
2. There are some 12v vacuum solenoids used on other vehicles that could be used in place of the non-available factory solenoid with possible wiring/connector modification. See picture 2 The vacuum solenoids are on or off electrically controlled valves and do not perform any modulation.

Quote:

**Keep in mind, the only function of this solenoid is to maintain the vacuum in the small vacuum reservoir when the engine is shut down. Solenoid closes to hold vacuum so it will be available for the turbo modulator valve the next time the engine is started. With the solenoid bypassed, vacuum will not be maintained and will have to build back up when the engine is restarted.

1.

2.

SJBrooks · **Joined:** Tue Mar 11, 2014 11:01 am **Posts:** 95

Thanks WW, I’ve always appreciated your timely responses. I tried the bypass option you mentioned, but there was no change in performance (I didn’t plug off the one now-open hose though). Do you think that means the root of the P0403 lies somewhere other than the vacuum solenoid? If yes, where?

Many thanks,

Steve

flman · **Posted:** Tue Sep 29, 2026 1:42 pm

SJBrooks wrote:

Thanks WW, I’ve always appreciated your timely responses. I tried the bypass option you mentioned, but there was no change in performance (I didn’t plug off the one now-open hose though). Do you think that means the root of the P0403 lies somewhere other than the vacuum solenoid? If yes, where?

Many thanks,

Steve

EGR code?

SJBrooks · **Joined:** Tue Mar 11, 2014 11:01 am **Posts:** 95

Yes, I see where P0403 is listed as EGR-related, but the only other time I’ve dealt with that code the fix was a new turbo vacuum solenoid. Maybe that “fix” was a fluke? My whole EGR system’s been deleted/disabled/blocked off. The electrical connector that went on the old EGR cooler is capped off/siliconed over and does dangle (though ziptied off) down somewhat low on the driver’s side of the engine. I’ll check that out and report back…

In the meantime, are there any other suggestions on causes/fixes?

Steve

WWDiesel · **Posted:** Tue Sep 29, 2026 10:32 pm

IF the EGR valve is stuck open and allowing boost to leak backwards through the valve and be dumped into the exhaust manifold, bypassing the intake, that would cause some bad low boost issues.
A mechanical boost/pressure gauge connected to the intake manifold would go a long way in helping diagnose what your issue is.
Also,
IF the FCV is stuck partly closed, it too could limit air flow and boost entering the intake manifold. FCV's are known for the small metal operating gears stripping and hanging up keeping the FCV butterfly plate partly closed and preventing full air flow and boost pressure from entering the intake manifold.

Best option, put in a blank between the EGR valve and the exhaust feed tube to prevent any backflow leakby.
Second, remove the butterfly plate out of the FCV so it cannot affect air flow or boost pressure from entering the intake manifold.

A mechanical pressure is really your friend when trying to diagnose low boost issues.

flman · **Posted:** Wed Sep 30, 2026 9:05 am

I eliminated bother my EGRs with Sasquatch kit.

SJBrooks · **Joined:** Tue Mar 11, 2014 11:01 am **Posts:** 95

Well, finally, I’m able to provide an update on the CEL codes referenced above:

The P0700 was caused by mice chewing through a wire that leads out of the TCM. Once fixed, this cleared the limp-mode problem (which caused the slow acceleration I mistook for a turbo boost problem)…

The P0403 is just a “stored” code caused by the full EGR system delete…

My little tractor’s now running as good as ever, and I appreciate y’all’s help!

Steve

WWDiesel · **Posted:** Thu Nov 05, 2026 11:33 pm

Glad you got it figured out and repaired! Maybe you need to get some of mouse repellent spray before you have another chewed wire event?
There are plenty of brands to pick from, I have no idea which one is best.
But having some treated wires beats not having any.
I have also read that keeping a light under your engine at night keep the rodents away, don't know how well this works?

This is one example:

SJBrooks · **Joined:** Tue Mar 11, 2014 11:01 am **Posts:** 95

Yes indeed, WW! I live on the high plains of east NM in cattle country, and field mice have always been a HUGE problem here, but this was a first-ever event for me. As my CRD is a back-up vehicle now (but a great one at that) and sits a lot, I’ve already sprayed the engine compartment and whole underside with a strong repellent and put some battery-powered ultrasonic sound/flashing light thingamabobs (found on-line) under the hood and on the concrete under it. We’ll see how well this works…

This winter’s task is to finally install the in-tank pump setup (with a hatch to it in the floor of the cargo area). I know there are writeups of this here in the forum, but if you have any additional advice on this I’d be glad to heed it!

Steve

WWDiesel · **Posted:** Fri Nov 06, 2026 5:02 pm

Is yours an 05 or 06 Model? Makes a difference on the wiring you have to add to install an intank fuel pump.

Found some good photos of removing the access plate and put them together that shows what is involved in making an access to the top of the fuel tank.
**NOTE: Some models did not come with access panel in place as reported by some members in the past. So you may have to cut a hole in the metal rather than simply prying off the sealed access plate. :banghead:

Not sure what the year or model cutoff was for NOT having the removable access panel???

SJBrooks · **Joined:** Tue Mar 11, 2014 11:01 am **Posts:** 95

Hey WW,

Mine’s an ‘06 and doesn’t have a stock access panel, so I cut one out of a junkyard gasser model (with some extra sheet metal around the panel). I’m gonna lay the new panel over the cargo floor of mine, mark it out, then cut about 1” inside of that line. I plan to use body panel sealant to glue the new panel down (incl from underneath the vehicle) so it’ll be water-tight.

As far as the wiring, I bought the full harness from ID Parts along with the pump; it should just basically be plug-and-play from that point (right?). I have already installed a fuse in the previously-unused spot in the fuse panel (#17, I think…), so that should just about do it (again, right?).

Let me know if there’s anything more I need to know/do on this task and, as always, thanks so much for your in-depth and timely replies!

Steve

WWDiesel · **Posted:** Sat Nov 07, 2026 12:17 pm

Yes, since you have a new 2006 harness, it should already be wired correctly for simply plug & play.
Fuse #17 (10 amp) and install a relay in position #38 and you should be good to go. See enclosed photo.
Don't forget to clock the fuel pump module correctly and swap out the fuel gauge level arm (float) using the original one from the old module.
Swapping floats will ensure your fuel gauge reads correctly.

Watch/Review this slide show, it pretty much covers everything: https://www.auerbach.ca/kj/lift_pump/default.html
It is for an 05 and a tank drop, but all the basics are still there for what you are going to have to do.

Hint: Be careful, when cutting the metal out over the fuel tank, be sure and stay very shallow, as there is not a lot of clearance between the top of the tank and the body panel.
You don't want to cut or nick any of the hoses or wiring while cutting out the panel. :juggle:

Good luck in your project! :rockon:

SJBrooks · **Joined:** Tue Mar 11, 2014 11:01 am **Posts:** 95

Awesome! Will let ‘ya know how it turns out…

Steve

Turbo vacuum solenoid replacement?

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