P1764 Code - Direct Clutch Solenoid Valve

S

shadow191

Premium Member
Premium
Location
Atlanta, GA
Car
2007 FX35
Anyone have any ideas on this? Couple of nights ago, I was in stop and go traffic and while inching forward, I gave the throttle a tap and nothing happened, it felt like something was slipping. CEL immediately came on and the FX felt like it was in limp mode. I go another couple of hundred feet until I can pull over and the entire time the car is struggling, like it's pulling a heavy load. After pulling over, I shut it off and checked for leaks, I thought I blew a transmission hose and lost all fluid. But that wasn't the case. And as soon as I crank the car back up, it's fine, but has the CEL. Long story short, I drove to dinner and home, another 10 miles and then pull the code which is P1764.

Not a lot of info on this code, but it's the direct clutch solenoid valve. If it's not working, the transmission won't shift and you are basically stuck in 4th gear. I found that out today when the code came back. On the highway, the car won't go above 4th and it starts in 4th as well, hence the sluggishness. I can replicate the problem anytime if I'm in stop and go traffic and I let off the brake and the car moves forward without throttle input. The instant I step on the gas, CEL comes on. If I come to a full stop and then step on the gas, it's fine and the problem won't come back until I idle again while moving. Once the car is moving, it won't happen. It's not mileage dependent, I can drive on the highway forever.

So after looking it up, it seems as if I have either a bad solenoid or it's an electrical issue. I'm leaning toward electrical because the problem goes away every time I shut the car off and restart. Something is happening at low speeds to trigger the problem. And coincidentally, I took the car in the day after this started happening to get new wheels mounted and when I went to pick it up, it was DOA. The battery cable apparently had come loose and I had no power. The shop showed me the positive connector was loose even though the bolt was bottomed out. Googling this, a lot of the Titan guys throw this code after their batteries died.

Anyone have any insight on this? I'm hoping it's just a little electrical issue that's making this happen. I'd really rather not have to swap the valve body. I have my old spare one since I swapped for Stillen, but it's a hassle and messy. And if I have to swap the VB, will that resolve my issue? I'm guessing it will since the TCM and all electrical connectors and solenoids that can cause this issue would be replaced. I saw some other posts here about other codes, but those were ABS sensors. I thought maybe the Stillen VB is incompatible since it came from a Z, but it's been working for 6 months and all my research said they were compatible down to the high/low ohm solenoids.
 
Yeah, I saw that so I'm going to check them soon and hope for the best. There was a ton of gravel and salt recently so maybe...And I don't have my rear splash guard on, the little one. The transmission is mostly covered by the front shield, it would be nice if that were it.
 
Hope thats the problem as well, as it would be a huge shame to have to swap back your factory VB.

Hope you find an easy fix...
 
Thanks, but I'm leaning toward swapping the factory VB back in just for peace of mind. It drove to work fine this morning, no CEL and no codes. But I was very aware and made sure not to coast and then give it throttle at low speeds. It seems that if it shifts to second, it's fine.

So doing some more research, I wonder if maybe the solenoids on the VB are acting up. For a while now, I've had a mild issue where there's a mild delay when shifting from drive to reverse. If I don't wait a couple of seconds, the car will rev up in neutral and then slam into reverse. If I wait, it's normal. And every once in a while, going from reverse to drive is the same problem. Never an issue if I'm going from park to drive or reverse. And sometimes if I'm slowing down for a light and then the light turns, if I'm going below maybe 10mph, and then give it gas, it will free rev for a second then slam into gear. I read up and apparently it's not abnormal for G35's to do this, so I never gave it much thought. But now that this is happening, I'm wondering if the low/coast solenoid is acting up. I'm only having issues in a coast situation; like the car is forgetting to re-engage the gear.

Fluid is still perfect, no burnt smell. Once the car is moving, it shifts perfectly and at WOT, snaps off clean gear changes as it should, no slip. If I get the code even one more time, I think I'm just going to pull the VB. I originally got it thinking I may boost the FX down the line, but I'm leaning toward not. And it doesn't really do much with just bolt ons. I'm AWD, so I can't chirp the tires or anything. I may just get Uprev and have the shifts tuned that way.
 
The Stillen valve body for the Z will work in our FX. No doubts at all! Do you know the history of the Stillen valve body you put in? If you need to put your stock valve body in, its a old time to install the transgo then. I've always hesitated to use a foreign.
 
Yeah, I'm not doubting the compatibility. The only thing I was worried about was whether the FX had the high or low resistance solenoid and mine should be high since it's a later model. All Nissans were high. VB supposedly was used ~3K after it was rebuilt by Stillen and car had ~46K.

I thought about putting a Transgo into my OEM VB, but I honestly think I'll just keep it stock. I know some people love it, but I've been on the fence about it since I installed it. I only did it because I got it for cheap and I was seriously considering boost. But with just basic bolt ons, it doesn't really do anything. I also don't like the sometimes harsh shifting at 3/4 throttle.

---------- Post added at 11:15 AM ---------- Previous post was at 07:08 AM ----------

And one more thing I noticed, the AT light doesn't flash. I read that for some similar issues like ABS sensor the AT light will flash before the tranny goes into limp mode. Not doing that on mine, just CEL and no shifting.
 
So I'm basically just keeping this updated for future people since I found almost no information on this code when it happened to me. Yesterday morning to work no problems at all, but the traffic was flowing pretty well. But on the way home, traffic was bad because someone called in another bomb scare and they had to block off some streets. If I stay stopped for more than 30 seconds or so, it will throw the code and start in 4th and tranny won't shift. If I stop briefly and start again, it will work. So it was irritating to say the least to keep shutting off and restarting the car at lights.

I thought maybe it had to do with the car warming up and hitting readiness before the CEL would come back on, but that's not it. Yesterday morning after I cleared the code I drove enough to hit all the readiness checks and the car was warmed up and no code. But in the afternoon as soon as I stayed stopped too long, it would limp. I'm wondering if staying stopped too long is shorting out that solenoid and then cutting the car off resets it. If I go into reverse and then drive, it will sometimes fix the problem. So for whatever reason, that solenoid is cutting out if I stay stopped too long. I checked the connector on the side, but that didn't fix it and I didn't think it would since it's the TCM and all the connections are on the valve body. If that connector was shorting out or dirty, I'd probably have more codes.

Well, just pulled my old valve body off the shelf and fortunately it looks to be in perfect condition (very glad I didn't get rid of it). I also happened to have enough fluid to do this so at least I'm not out of pocket any money for this. Just really not looking forward to dropping the pan and wasting 3 hours of my weekend.
 
Ok, swapping the VB did resolve the issue. Stillen looks fine, no idea what's wrong with that solenoid. When I had both of them off, I considered swapping just the solenoid from my OEM one to Stillen, but I didn't want to risk any more down time in case that wasn't it. If I had more time to play around, I would have done it and tested it. I did this at my FIL's because my building frowns on transmission work in the parking deck (I know from first hand experience) so I had to get the car back up and running to go home.

I do miss the crisp shifts from the modded VB, but I think I prefer the OEM for my setup right now. The shifts are smoother and it doesn't jump forward on every shift. That's fun sometimes, but not when you're just cruising in traffic. If I do ever boost the FX, I'll swap a Transgo in.

And if anyone wants a really cheap Stillen VB (for 06-08) that needs a solenoid replaced, PM me. They don't sell solenoids separately, but if you have your OEM VB and some down time, you could swap that over. It's just taking up space on a shelf now.
 
Glad you got it back up and running. As this issue only presents itself in stop and go traffic, it sounds like a temperature related issue. Not saying your temps are too high, its possible that it affects a component that is failing when it hits a certain temperature.

Its possible the solenoid fails at a certain temp, so when that happens the solenoid doesn't work as its intended to be and causes the transmission to go into fail safe mode.

This is a theory, I could be wrong but worth mentioning it..
 
That is one of my guesses as well. It only happens after the car is warmed up and in stop and go traffic. So maybe once it hits operating temp, solenoid sticks and causes something to short. If I shut the car off, it fixes itself, but if the car is warm it comes back very quickly. I believe that solenoid is the one that transitions between neutral and drive so that's why it doesn't happen if I'm in gear.
 
I don't know if the Stillen did or not. It's effectively the same thing as a Transgo, so maybe guys who have done that would know. I'm not sure how it impacts shifting so I don't know if it's modded. The VB mod should only modify the valves/springs for the fluid paths that impact the 1-2-3-4 shifts. I don't believe the 4-5 is touched at all. So I don't know if anything was done to this valve/solenoid.

I thought maybe it was a wiring/connector issue, but all of the connections from TCM to solenoids are internal and I didn't crack the VB open to check.
 
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