2005 G 35X and it has a Automatic transmission which works fine in Drive, but when you push the shiftier handle to manual the transmission stays in Drive and works fine downshifting and upshifting Automatically

 

Yep

 

Whatchu talkin' about Willis??

 

 

99% it's either valve body or the actual switch inside the shifter assembly. Verify that the manual mode switch is actually activating, it'll be a tiny little *click* as it goes from D to manual mode (taking offer the shifter assembly cover may help to hear it; lower silver trim on shift handle, remove gold colored pin shaped like a "U", remove ****, use a trim remover to pry the shifter assembly cover off. It'll be attached to the car via two wires, but you can just put it on the passenger side, those wires control cigarette lighter and IIRC illumination on the cover itself). If it's clicking fine then either the processor is broken or your valve body has a solenoid going out (could be either at this point). On a cold start, go to D and then quickly (within a second) to manual mode, while the transmission is cold (AFTER RPM has dropped to under 1100 in P, no need to shock the system). If the transmission consistently lets you do that but refuses after driving for a bit (hot fluid, especially in city driving), it's most likely your valve body solenoid, as they act up more as temperature goes up. On a hot start, go from P to D to manual mode in under two seconds within five seconds of starting; if the transmission lets you do that, even more evidence for a valve body problem (IIRC the car takes a few seconds to run temperature/sensor checks upon startup and if you can get into manual mode before it checks transmission temperature, it'll let you go in. If you go back to D and stay there for more than a few seconds though, you'll be locked out. It also won't let you downshift, but it should let you upshift (transmission trying to protect itself from potentially damaging RPM levels)).

In either case, it can't hurt to grab some compressed air and give the inside of the shifter assembly a good blast; sometimes the grease down there/debris can interfere with operation. Unfortunately, dealerships and transmission shops can't test for bad valve body solenoids without physically taking the valve body apart and testing resistances. The car should run an invisible code (no SEL light) P1815 if the manual mode switch itself isn't working, but from what I remember when I had this problem, that code can come and go randomly. The valve body runs around $1800 from most dealerships; I'd honestly go aftermarket with a shift kit if you're going to replace it.

EDIT: Important! I totally forgot, check your ATF level before any of that, and if it's low fill up with Nissan J-matic or S-matic. Google the correct way to check the level, it's a tiny bit more complicated than checking oil. Low fluid can cause all sorts of issues.

I suspect valve body solenoids overall, but it could be the manual mode switch itself. You can't get that by itself unless you visit a junkyard and pry it out of another car's shifter assembly, but then you're playing roulette with if that car's assembly works. The assembly is $500 from most places and about a 20-30 minute install with basic hand tools

 

So is it the consensus that the valve body is the issue with these cars. Next question is if i pulled the valve body out of another tranny will i have to get that valve body reprogrammed to my car or is it a direct swap as long as it is the same year?

 

Hopefully its just a direct swap and not needed to reprogram

 

Both the Valve Body and Shifter Assmebly require reprogramming!

2005 G35x Manual Mode/M intermittent / works 20-30% of the time ....Been through hell and back with this issue. I just want to finalize it as nothing else major is wrong my 05 G35x ... It's got high KM, 230+, but runs like a dream!Sometimes it will stay in M-mode the whole trip, but MOST of time its kicks back into D after about 5-10 seconds after starting the car and driving. Once it fails, it will not register M mode until you the next time you drive, potentially lol. Occasionally, you can turn off the car and restart it and it will fix it. Also, the downshift/upshift doesn't register sometimes and may take several taps to actually shift, but it's the downshift really 99% of the time... it also very rarely will shift own its own in M-Mode, down shifts only, without human input, which is very annoying, but this is rare. Outside tempature also seems to affect its oeprtion of working or not. I'm sure all the issues are related to one thing... I hope! Because it does work fine sometimes...

Work done already to address this issue:
- Replaced shifter assembly - as suggested by Infiniti ( Did not work ) Cost: $1000.00
- New valve body/TCM - as suggested by Infiniti , was covered under my used car warranty ( IT DID NOT WORK ! ) only had to pay $700 under warranty, would've been $2,800 otherwise..

Now Infiniti is saying it's my combination meter ( Guage Cluster ) , showing code: P1815 Manual Mode Switch - I'm RELUCTANT to listen to them anymore... Quote on the Combination is $2000, but I’ve been looking into used ones or refurbishing my current one for much, much cheap than that. My warranty might cover it, but I hate to waste it on issues like this! It does make sense that this could be the issue though, but why wouldn't they diagnose this in the first place?? Dealerships are total rip off! but most places say they are your best bet for this issue...

Some other research I've done, people say it could be a cam sensor, but I don't see how that could cause all these issues...Could it be a speed/wheel sensor? Tranny fluid?
????????

It does have a minor electrical issues in the combination meter - left turn signal on dash is faint inside most of the time, and sometimes work normal, and the gas gauge gives a faulty reading. I don't think this is this all connected to the M-mode issue and the combination meter? Am I going to just keep wasting money, or, have I eliminated all possible causes and the combination meter ( Gauge Cluster ) is the fix?? I need this fixed now!! LOL! The Transmission seems to work fine otherwise, I hope it's not the tranny!

Please help!!!

 

No they don't REQUIRE programming but it probably had an older software installed so they updated it to the latest. Either that or they didn't actually give you a 2004.5 transmission. Also, the valve body is just a bunch of solenoids, the shifter assembly is just linkage and a couple contact switches, the programming is done on the TCM. Shifter assembly is 100% plug and play, no programming required. There is a lengthy DIAGNOSTIC procedure they follow though when trying to determine the problem but that's NOT programming.

Did they replace the MM switch when they did the shifter assembly.

Did they clean the transmission ground on the front of the timing chain cover.

When was transmission fluid changed and what is it's condition.

Usually these problems are the contacts on the MM switch itself getting corroded, however it can also be caused by low line pressure on the transmission or many other reasons, since you're throwing the MM switch DTC then you either have a failing switch or possibly damaged wire/harness.

 

Thanks for your quick response!

I know the shifter assembly needed to be (flashed) at the dealership, once intsalled, the assmeby was installed at a tranny shop and they sent it to infiniti to be flashed.. is that not programming?

Infiniti said the M-Mode swtich is operating normally, and they checked all other connections, No LAN/CAN faultslogged in any system.

Tranny fluid was replaced when the valve body was done, in the beginning of 2018, just had an oil change last month and they said all fluids were great.

Thoughts? do you think it could be the gauge cluster?

thank you !!

 

Here is the last report from Infiniti after I got the Valve Body replaced...... See what you think?? thanks again!

 

Combination meter failure won't cause that problem, it just reads CAN data and displays. They found a constantly open wire in the MM circuit but the switch functions, that means a wiring or harness issue.

 

Yea, I thought it seemed strange the issue would be in the meter.. I'll go get the wiring and harness checked out, and post an update. Really appreciate your help!

Thank you!!!

 

Wait, somebody else with the faint/not working left turn signal on dash and bad gas gauge? Tell me, is your parking brake light also iffy? Sorry to thread hijack, but I had to take apart my gauges last year and have had those problems since.

I've also got the issue with the car not wanting to downshift sometimes, yet will always upshift in MM (don't have the issue with the car not wanting to go into MM anymore since my transmission replacement, although it has happened once or twice in a year). Seems like we have very similar issues; for what it's worth, I've replaced both the entire transmission/valve body and shifter assembly with no true fix for the no-downshift problem. My guess is it's an electrical problem SOMEWHERE in the line (already cleaned every ground in the car)

 

Hey Mag,

Yes! Very similar problems.

Also, my reverse lights do NOT work on occasion... but work 70-80% of the time. But for your parking brake light issue ( on the gauge you mean, correct?) .. I had that happen to me to! The parking light brake can mean low brake fluid I beleive , I had that flashing before and that was my fix. If it gets really low, the brake, SLIP and other VDC will all come on at once .( to my knowledge )

If I had known this manual mode issue would be such a headache and $$$, I would've never got an A/T, but I wanted the AWD to drive year round .( Really regretting it now, espescially to gear down in winter, etc.) I thought I would be able to fix the issue with some of the quick fix methods. ( yea, maybe your down shift issue is something in your wiring to , if it is still happeing even after your new tranmsisson ). Did your car have the same issue as mine before the tranny replacement, M-Mode would stop working and only work 20-30% of the time? because if that will help... I would do it.. love this car, but it's a fnn drag with no M-mode... it's really getting to me! Losing sleep over it! LOL! . I still think for my issue it has to be the wiring/harness etc, as "Cleric670" has informed me of and seems to make the most sense. I will get that wiring/harness checked and post updates. """"""@ MAG and "CLERIC670" : I will also see if they replaced the MM swtich when they installed my shifter assembly, as you mentioned, but is that not part of the assmebly, or is it a seperate part? That would be a very logical explantion for these typese of issues I'm having if that''s the case...?????? """"

Where did you get your gauges done? Or, did you just take it apart yourself... I was looking into shpping my off for refurbishing in Toronto ( I live in Vancouver, BC) they said they can fix the singal and gas guage 100%, but when I asked him about the M-mode indicator on the gauge, he said he's never done that, and I said infiniti told me this could be the issue, he said can't promise anything and doesn't think that would be the problem anways.. I've learned where my tank goes empty (the hard way, only one time) at 1/4, so I always keep it above 1/2..and I'm so used to the left signal not working most of the time that i don't really want to have it taken out and redone, the car would be off the road I beleive and costs would be between 200-400$ with shipping and repair... So if it's not going to fix my shift problem, I might just live with these smaller issues on the gauge.

Side note: I just popped on a MagnaFlow catback exhaust and lowered it! picking it up tomrrow. I need this M-Mode problem delt with now..I can live with the occasional missed down shift if that's as good as it can get! lol!

Thank you for sharing your VERY similar story MAGNEU... any comments, updates or recommendations would be greatly appreciated!

CHEERS!