ok so in the mornings when cold (florida cold, so we're are talking at worst 50 degrees), the trans shifts REAL hard going up and down(throws the codes), until it warms up, then it behaves.

so P1716 is the turbine revolution sensor, which is the first sensor (closest to front of car) on the tcm (Transmission Control Module - on the valve body itself)...not replaceable by itself. Don't know what the second sensor is called that is right next to it(again on the tcm)

Someone I spoke with who sells remanufactured valve bodies says the sensors need to protrude through the tcm's plastic housing the thickness of two nickels. If it is 1mm short of that the sensor might not read the speed and throw the code.

P1815 is the manual switch circuit...now when you use your shift lever and push it to the right to go into Manual Mode that depresses a micro switch and tells the tcm that you are in manual mode, when you push up on the lever it momentarily presses another micro switch and tells the tcm to up shift, and when pulling back on the lever there is yet a third micro switch to tell the tcm to downshift.

My problem is I don't know if P1815 is referring to the shift lever's switches or the switches inside the tcm. I suspect it is inside the tcm

I have a nice scanner that reads live data from various systems, and under the transmission system I can read live data from the micro switches and see that the micro switches does indeed tell the tcm that the switch is on or off .

My gut is NOW telling me that when the TCM can't properly read the Turbine revolution Sensor's speed, it puts the transmission in Limp Mode (or similar) and prevents Manual mode (when the transmission acts up the display on the dash stays as D even if I try to go to manual) and throws P1815 too.


has anyone drop the valve body, taken off the TCM and inspect the two sensors to see if the amount they protrude can be adjusted?

Two places I found that remanufactures valve bodies are
https://streetsmarttransmission.com/rem ... alve-body/ - and will cost $740 (in Tampa, Florida)
www.softelectronic.com (out of Bulgaria of all places) and will cost $400...I don't think I'll go that route
(the valve bodies need to be flashed properly for your specific vehicle so be careful with that....both companies will do that)

https://www.nicoclub.com/FSM/G35/Coupe/2005/at.pdf

Don't know if you have looked through the FSM for this but it's linked above. This could be anything from faulty switches and components to bad electrical connections. Unfortunately I don't work on transmissions and can't help too much. Based on what you are seeing it seems to not be the micro switches but I would check proper continuity anyhow.

Good luck, hope you figure it out.

Thanks for the reply , yep read the sections over and over again.

I've come to the conclusion that the TCM is putting the transmission into a mode that Manual Shifting is disabled when it throws the 1716. So concur that the microswitches in the shifter is NOT the problem.

So here is our new SOP (standard of operation).
We warm up the car to operating temp for about 5-7 minutes, before we attempt to drive it. AND surprisingly that DOES IT!!

Using my new scanner and reading live data of the engine rpm compared to input shaft rpm....I can see that ONCE warmed the RPM are close to being even, which is what the FSM says it should be....when cold the numbers are WAY off and when the CEL will come on and shifting acting poorly.


SOOOOOOO at this point I believe it IS an electrical connection on the TCM that makes a proper connection once the fluid is warm.

Just haven't dropped the valve body yet to inspect the TCM....and not sure I would find something either....

It is a messy job...but a couple of hrs to drop could lead me to finding the bad connection....but it could also NOT.....I am 99.99% a NEW-to-me remanufactured valve body would resolve everything...


I'll keep this thread updated.

UPDATE: So we've been living with the TCM/Valve body issues since Feb, byt simply warming up the engine, and driving it around the block in Gear 1. Once warmed up it shifted fine for the remainder of the day until cooled down enough.

Saturday we had our first issue whilst driving. We were on a highway and wife driving and knew the tranny threw the p1716 code as it was reving more than 3K at 75mph....(when I drive I perdioscally put it into M mode and see what number gear it is in if it says D I know it has to be turned off and back on to reset...)....so at speed it just slips out of gear out of nowhere and revs up to 7k...woman didn't know NOT to keep reving.

turned on hazard lights on and pulled over. Had her turn off the car wait 5 seconds and then restart the car. Put it into D and it drove fine for the remainder of the trip with the RPMs coming back down to 3K.

The next day (coldish day for FLorida mid 50s)) we did our normal warm up procedure then when to the grocery store....the tranny didn't want to shift pass 2md gear. Got to the store did our shopping and same thing on the way back...including the car starting to overheat.


using my new scanner, after the gear slippage I have WAY more codes now...some are related to Tire Pressure monitor, but most have to do with the tranny and valve body.
they are :
tranny related
P1730 - turbine rev s/circ
P1730 - Interlock
P1774 - L C brake solenoid
P1731 - 1gr e/braking

TPMS related
C1109 - Battery Voltage (abnormal)
C1709 - FR (this is the front right TPM sensor)
C1724 - batt volt low FL (front left TPM sensor)

ABS related
C1132 - engine signal 3
P1212 - TCS/Circ

Misc
P0455 - EVAP gross leak
U1000 - cam comm circuit
B2013 - strg comm1

Sounds very much like that TCM is dying. The ABS codes are residual, from not getting proper speed signals from other ECU's when they go limp (in this case the TCM). By the way, Nissan TCM's that live inside the tranny all have a nasty habit of crashing the entire CANbus when they finally die. You put a scanner on it and only one or two ECU's show up, or maybe none at all. You disconnect the tranny and shazam, everything else wakes up and says hello with "U" codes everywhere. Bite the bullet and replace it before it bites your butt.

VStar650CL wrote: ↑

Mon Jan 11, 2021 12:59 pm

Sounds very much like that TCM is dying. The ABS codes are residual, from not getting proper speed signals from other ECU's when they go limp (in this case the TCM). By the way, Nissan TCM's that live inside the tranny all have a nasty habit of crashing the entire CANbus when they finally die. You put a scanner on it and only one or two ECU's show up, or maybe none at all. You disconnect the tranny and shazam, everything else wakes up and says hello with "U" codes everywhere. Bite the bullet and replace it before it bites your butt.

Thank you for the reply and knowledge... I like it when people explain the whys ...I am child like that ' but why?'

yeah biting the bullet...cheaper than a new car.

I hope I don't have the dreaded coolant in the tranny syndrome. I'd prefer a separate tranny cooler...but I guess they want it internal to the radiator to warm up the ATF.

I'm going to go with these guys.
https://streetsmarttransmission.com/rem ... alve-body/

You're most welcome. Coolant in the tranny is easy to check, just pull the stick. If it's milky and opaque, it's too late. If it's slightly-milky but still translucent and pink, you can probably save it with a complete flush. Just have it towed if that's the case, don't put one more mile on it. The fluid will need a near-complete exchange, so a running power-flush is required to clear out the fluid in the torque converter. Merely dropping the pan won't do it.

VStar650CL wrote: ↑

Mon Jan 11, 2021 2:35 pm

You're most welcome. Coolant in the tranny is easy to check, just pull the stick. If it's milky and opaque, it's too late. If it's slightly-milky but still translucent and pink, you can probably save it with a complete flush. Just have it towed if that's the case, don't put one more mile on it. The fluid will need a near-complete exchange, so a running power-flush is required to clear out the fluid in the torque converter. Merely dropping the pan won't do it.

Good news...the the ATF is perfectly clear.

cfauvel wrote: ↑

Mon Jan 11, 2021 3:08 pm

Good news...the the ATF is perfectly clear.

Sweet. New VB and you should be fine.

VStar650CL wrote: ↑

Mon Jan 11, 2021 3:39 pm

cfauvel wrote: ↑

Mon Jan 11, 2021 3:08 pm

Good news...the the ATF is perfectly clear.

Sweet. New VB and you should be fine.

UPDATE: today I tackled the Valve Body replacement....wasn't too bad but very messy...not fun doing it on your back.

The bad news is....I think it might have been a wasted effort or will only work for a short period of time...here's why I say that.
The ATF that came out, on a dipstick looked fine ...no milkyness and no signs of coolant in the pan or on the TCM, BUT the two magnets were pretty fluffy..no metal chips or anything but definitely something on there. Also when the ATF was poured into a clear container, the fluid was damn near black.

I bought 5 quarts of the Nissan Matic-S ATF, but counted 6 quarts captured. I have another 2 quarts coming in tomorrow and tomorrow I will start the car.

With the remanufactured Valve Body came instructions to do the following re-learn procedures
1 - Accelerator Pedal Released Position Learning
2 - Throttle Valve Closed Position Learning
3 - Idle Air Volume Learning.

We'll see tomorrow

I think the dry capacity on those is 11. If it's that dark but behaves itself after you fire it up, you might want to give it another change on a very short interval to remove some of what was left in the torque converter.

VStar650CL wrote: ↑

Sat Jan 16, 2021 7:06 pm

I think the dry capacity on those is 11. If it's that dark but behaves itself after you fire it up, you might want to give it another change on a very short interval to remove some of what was left in the torque converter.

Just looked it up indeed and indeed it is 11 quarts...i thought it was 17 quarts...but nope 11...

Yeah good idea on doing another change in short order. the damn ATF is 15$ per quart

UPDATE: Ladies and Gentlemen,
WE HAVE A WORKING TRANSMISSION!!

I got my extra two quarts in today. Put the 6th bottle in and took it down the block...Already could tell the shifts were pleasant...(2-3 was a little harsh, but NOTHING like it was before).

Took it on a faster road and the shift were all smooth and went into to 5th. Took it easy for a good 15 minutes. The onto another fast road and put the throttle down enough to make it rev in the 3k area to get away from the traffic that were coming up behind me and all shifts were smooth.

Got home and checked the fluid and it was reading low for being hot...ended up putting in another 1/2 quart.

Tomorrow will be a good test...drive it with out the requisite warmup drive in 1st down the street... fingers crossed.

I'm having same issues now. So you also didn't replace the shift selector that controls the manual mode?

Are you saying only replacing the transmission fluid solved this problem?

No did not change the manual mode switches. I believe that when the TCM throws the code P1716 it turns off the ability to use the manual modes in order to protect itself.

The fix was NOT just transmission fluid...it WAS the valve body...so far STILL so good. Optimistic that it will last at least a year. I think the valve body has a 3 year warranty...have to double check that

So I thought I'd give an update as the new valve body was just a temporary fix, sadly.

on 12/31/2021 I was on my way to see to Miami to get my mother to the ER (250 miles away) when at highway speeds the transmission felt like it went into neutral. Turned around, parked the car and took another car down to Miami, where I stayed for 2 months to take care of her.

While I was down there I had my wife have the car towed to the transmission shop that had a relationship with the company that sold me the rebuilt valve body. The code that it was throwing was the same P1716 and U100 Can communication circuit fault. I had them rebuild the transmission to the tune of $3185.00. Included a new torque converter ($279.00), soft parts/overhaul kit($489.00) , Hard parts (electronics, direct drum, forward drum, reverse drum, planetary gears, case bearings, shafts, pump, and valve body (as needed....$289.00)

Re reviewing the invoice I am starting to suspect that they reused my valve body.

well on 12/8/2022, less than a year the transmission throws P1767 HLR Clutch Solenoid Circuit Fault and P1212 TCS communication line circuit (the latter deals with ABS, so unrelated). The symptoms were: Not go forward when in D and foot off the brake, and creep slowly when pressing on throttle. They found a faulty ground somewhere on the valve body and replaced the valve body under warranty. I have until 1/12/2023 in case something else happens.

So far so good, but has only been 4 days.

whooo doggy another update

So on January 4th 2023 things started getting funky. Service engine light comes on and I see CAN bus codes.
No driveability issues YET, then jan 7th I take it the car wash and come home, it sits for several hours and we try to go to dinner with friends and it doesn't start. Just cranks and ALL the lights on the dash come on and headlights come on and off by themselves. WTF I say to myself.

this time my scanner reports 12 different faults, most of which are c1000 and c1001. SLIP and VDC OFF lights are one

A few days go by, I'm trying to get the car to the place that repaired it last time, but AAA fails me (which is actually ok) and the car starts just fine and the only light that is on is the expected Service Engine Light. I cancel my appointment with the previous repair shop, which is good as they are SO FAR away.

Now I am suspecting that it is a short related to water, from the car wash. The car wash has an undercarriage spray nozzle.

on Jan 9th, I decide to test that theory. Driving to the car wash no issues, only service engine light is on.
Drive back from car wash, no issue.
Let it sit for a little over an hour and try again, and sure as s***, all the dash lights light up, headlights do their own thing.
After an a few more hours I try again and the car won't go past 1200 rpm...so I take another car to the gym.
At midnight, I play with the car and I can get past 1200 but MPH and RPM don't read, VDC OFF and SLIP are still on, but car shifts.
As it warms up more, the MPH and RPM come back.

yesterday I found a shop that is familiar with CAN bus issues and driving there the only dash light on was the Service Engine.

Damn it...did the car wash undercarriage nozzle the reason that I was getting the P1716 all along? At 230K miles the transmission NEEDED to be done...so I'm ok with it....but damn a lot of money has been spent on what ultimately is a water short on CAN HIGH/CAN LOW around the transmission.

Could be Sun roof drain problems from under dash been having issues with my 07 but it's a little different set up. Check harness connections grounds and bcm mine was very corroded up but I think it may have been ok. Turned out the ipdm was the starting issue. But after getting wet one time everything went crazy. Now having transmission problems ever since.

Jeremy5619 wrote: ↑

Tue Jan 31, 2023 7:38 pm

Could be Sun roof drain problems from under dash been having issues with my 07 but it's a little different set up. Check harness connections grounds and bcm mine was very corroded up but I think it may have been ok. Turned out the ipdm was the starting issue. But after getting wet one time everything went crazy. Now having transmission problems ever since.

You could absolutely be right....I just thought it was something around the transmission as that has been an issue in 2022.
But ANY module or its wire loom that is getting wet can be the culprit. The car has been in the shop for 3 weeks today...I don't think he's doing anything...so will probably pick it up this week. I going to get a PICO scope and try to reproduce/diagnose the problem myself.

UPDATE: Holy F'ing s***!! the mechanic found the issue. He spent hours in and around the transmission and found nothing (that is going to cost me a chunk). Then he poured water down the windshield and it happened for him!!.... The area where the IPDm sits would fill with water from a blocked drain and literally sit in a bath !! He took it apart and cleaned everything and unclogged the drain. He seems to think water was coming up through the wiring harness opening not from the top where the plastic cover is.

Doh!

VStar650CL wrote: ↑

Wed Feb 01, 2023 1:04 pm

Doh!

what are your thoughts Vstar?

I'm not an Infiniti guy, but I recall one gent in the forum here who had exactly the same situation on a Quest van. I've seen a couple over the years as well. It only happens on certain models, but it's a hard nut to track down without getting yourself wet. Big kudos to your technician.

VStar650CL wrote: ↑

Wed Feb 01, 2023 1:21 pm

I'm not an Infiniti guy, but I recall one gent in the forum here who had exactly the same situation on a Quest van. I've seen a couple over the years as well. It only happens on certain models, but it's a hard nut to track down without getting yourself wet. Big kudos to your technician.

Big Kudos indeed, especially as I steered him towards the transmission because of all the work done. I feel like a jerk..but I'm sure I'll be paying for the diagnostic. Thinking of getting him a bottle of champagne above the fee.

when you did the DOH I thought you meant "yeah of course, dummy"

Not at all, but if you're the tech, you feel that way when you finally see the puddle and figure it out. Like, "Well, crap, why didn't I put a hose on it 4 hours ago?" So the "Doh!" was for me and not you. Been there, done that.

VStar650CL wrote: ↑

Wed Feb 01, 2023 2:07 pm

Not at all, but if you're the tech, you feel that way when you finally see the puddle and figure it out. Like, "Well, crap, why didn't I put a hose on it 4 hours ago?" So the "Doh!" was for me and not you. Been there, done that.

ahh ...yeah never would have thought to look there....I was going to get the car back, buy a PICO oscilloscope and find a module to back probe CAN hi/lo and start splashing water around the transmission to see if this was a Can Hi short to ground, Can Lo short to ground, Can Hi resistive short to ground, etc....and still wouldn't have caught what it was.

Your Pico would have seen some nutty behavior if you discovered the IPDM puddle, one of the two CAN terminators is inside the IP. Add a water short and who knows what would come out. As the sub commander quipped in Red October, could be measurements for Playmate of the Month. Your guess is as good as mine.

VStar650CL wrote: ↑

Wed Feb 01, 2023 4:55 pm

Your Pico would have seen some nutty behavior if you discovered the IPDM puddle, one of the two CAN terminators is inside the IP. Add a water short and who knows what would come out. As the sub commander quipped in Red October, could be measurements for Playmate of the Month. Your guess is as good as mine.

Right?! it wouldn't have shown up as a known BAD waveform (I don't think)

Just some crazy waveform...and I guess would be true ANYWHERE on the bus or any other bus that goes through the IPDM

...I've signed up to Mechanics Mindset (an online course) courses and I'll post what my mech found and see if he can reproduce the issue or at least see what HE thinks the waveform would have looked like or maybe some tips for future pinpointing. I think my mech got lucky....I got lucky.

Oh and this AM...the 350z won't start....good battery, I can hear the fuel pump go....just no crank...the car started and ran fine last night....ugh.