Hello guys, new here, first of all sorry if this is in the wrong area

2003 G35 coupe, 215,000 miles
Just a few days ago during a heavy rain my G left me stranded. I started the car, reversed out of my spot, and then I put it into drive and felt a huge clunk coming from what I believe is the transmission. This happens in reverse as wel and you can feel the whole car jump when it does this.
As I put it in drive and started to accelerate, I had almost no torque and seemed to be stuck in a higher gear(4th I believe) so I put it into manual mode and the gear indicator on my dash said I was in first, so I drove it to see if I could shift it up but it changed from 1 to D while still in manual mode. I restarted the car, same problem but this time my AT check light flashed for 8 seconds. I scanned a code and got p0720, p0740, and p1564. Never had any problems with these. read that this could be a speed sensor issue but after resetting the battery and unplugging and plugging back the TCM I was given a new set of codes, u1000, u1001 and c1136, which are related to the CAN and ABS. I’m believing my IPDM or TCM got wet because I found water on my wires leading to the TCM from the ECU, and there was also a small puddle where my IPDM is located. Idk where to start besides replacing my TCM with another one to try and see if this fixes it. Any other suggestions? Thanks

 

Was the puddle simply in the battery compartment or was is actually inside of the PDM? The drains for the battery compartment often get clogged and is an easy fix. Nissan did a terrible job on their design when routing the main wiring harness into the car. Under the cowling, you could see how standing water can easily form around the harness. I used RTV as a temporary fix when the seal was leaking. Unplug all of the connectors to the ECU and see if they are wet or have any sign of corrosion on the contacts. There is a possibility that something was shorted with the electronics and unfortunately a shop would be better prepared to diagnose that. Since the IPDM is the hub for everything, I would start looking there for corrosion or water leaks.

 

I meant there was a puddle right underneath it in the cowel, and yeah I unclogged it yesterday trying to see if it would dry up and fix itself but it didn’t. I’ll check all connections around the ecu and IPDM when I get back home from work, thanks for giving me a starting point. If anyone else has experienced this please let me know any symptoms/fixes you’ve dealt with

 

do you think it’s possible the TCM if fried? That’s my first idea because the harness that plugs into that was wet and had water on the connectors. I Sealed the seal by the windshield wiper motor area with silicone in hopes of stopping the leak

 

Buuump someone anyone help pls

 

When my IPDM got flooded with water everything was happening. The horn wouldn't stop blaring, reverse lights always on. Really check it isn't all corroded. I had to clean mine out.

 

yeah I haven’t had anything like that happen which is leading me to think it’s something with the tcm, but it probably wouldn’t hurt to check and consider the ipdm

 

My suggestion would be the same, start where you found the water and get a good contact cleaner, a fine brass brush and start cleaning things up. You might have a dead player in there but cleaning things carefully might get you running again too. Good luck!

 

I don’t see any rust or burns from the water contacting anything so I’m just going to try a new relay for the TCM and then a TCM, if I do notice anything I definitely will, thanks for the pointer

 

SOLVED

I left my g alone over the course of 4 days, 2 rainy days(covered) and then 2 days with no rain, and something seems to have fixed itself. This proves something was most likely wet, considering a similar issue has happened before, during the rain, but also fixed itself after sitting or “drying out” hope this helps someone else, if it didn’t fix itself, my next order operations was going to involve me replacing the Relay by the TCM(in 03-04 models the tcm and relay are in the right side kick panel under the glove box), and after I would examine and try to manually dry or clean any damage on the wires leading to or the ECU/ibdm/tcm themselves, and if that didn’t work, replace the TCM with the same model, drive/tow it to a Nissan dealership and have them reprogram it in hopes of it being fixed. If that didn’t do it then I knew it was something electrical. If that wouldn’t do it I’d try a transmission last resort. After that I’d sell it

 

After another heavy rain my car went back into fail-safe mode and the tranny wouldn’t move out of 4th gear. It actually started running fine until I swung a u turn kind of hard(missed my car, been driving a 4cylinder) right after that I knew my car was in fourth gear because
my acceleration decreased majorly. I got back home and tried resetting the car to see if it was just a fluke. AT Check light flashed about 8 times and so I swapped the relay by my TCM(on 03-04 g35 it’s not located in the trans but under the glovebox on the right side wall) with the same type relay I found under the hood near the battery(the left-most blue relay in the pic) started back up, AT light still flashed but my car seems to drive normal again. Just have to replace the reverse lamp fuse now (the one I swapped with)


Blue relay

 

I’m having the same issue noticed it one night driving in the rain my gear indicator went blank and didn’t know what happened got home turned the car off tried to start but got nothing only hear the starter going left it alone next morning car was fine. 3 months later it’s snowing, I was driving with VDC off and the right side of my G drive over a puddle that’s mixed with snow and my gear indicator went blank. This time my Gs transmission didn’t know which gear to be in and shifted late CEL came on, I made it home car was stuck in 2nd gear the whole way and turned the car off and tried starting again same symptoms no crank nothing just the starter. I left it for 2 days it didn’t start I restarted the ECU and drove it around the block the car was stuck in 4th gear to get some codes to pop. Got P1762 and the crank sensor probably from the car not starting. Checked my fuses and relays there all good. Car has 113k on it 04 Coupe OEM everything.

 

I’m thinking your problem has something to do with it being wet as well, check underneath the fuses by the battery to see if waters puddling up, the IPDM/ECU are right there I believe and if those get wet, then certain important components aren’t getting the power they need. Also read my posts and check the TCM relay and try swapping it out with the relay used for reverse lights and see if it runs normally. to me it sounds like an ECU Problem since your display isn’t signaling which gear you’re in, theres a ton of threads on here explaining how to reset the TCM or ECU without having to have the dealer flash it for you. If none of those work I still believe it’s something to do with the ECU getting wet. Look everywhere for signs of water/dust/rust and maybe that’ll lead you to your solution as it did me. Is there a wet spot on the carpet of your passenger side in the very far front right corner? If so then most likely something in that area is the culprit. I believe most codes thrown when this area gets wet are just generic codes due to the computer not knowing what’s actually not working

 

if there is a puddle then take a long philips screwdriver or something similar and feel around for gunk and try to push your way through, I would remove the battery if you do see water puddles up to make sure you clear up that area to eliminate the possibility of it being something there getting wet

 

P1762 is the direct clutch solenoid on the TCM however I don't think that's the root issue, that can show up anytime the ECM has a fault from the CKP or CMP sensors.

Your CKP sensor code is there for a reason, the ECM didn't get a signal from it.

Do you have the undercarriage cover on the vehicle? If not then you're pouring water into your computer and will have a TON of problems in the future. If you do have the undercover installed then you're probably just experiencing a failing CKP sensor and the TCM went limp mode as a failsafe.

CKP sensor code doesn't show up "when the engine fails to start" it shows up when "the engine is trying to start but the sensor is sending back no data to the ECM".