Alright so this car was bought back in 09 with the story that it was owned by a guy cheating on his wife and when she found out she put a hose in the sunroof and filled the car with water. Supposedly explaining the rebuild title fast forward a few months the engine started to rap A lot ended up replacing the short block using my rev up top end parts while replacing the engine noticed that the radiator shroud had a perfect line of rust about half way up making me realize the car mustve been driven into a pool of water instead of the story I was given after a lot of work and testing and trying ive been unable to figure out these last remaining issues and was wondering if anyone had some clues. First off since ive had the car the VDC slip abs cel and airbag light have not turned off once. The nav system intermittently decided to get a purple hue but otherwise works fine the radio has since developed a slight whine with rpm assuming its interference from something. The radio controls on the steering wheel have never worked but the horn and cruise all function. The oddest issue is the speedo it reads completely accurately until 60mph then it wont go above 60 no matter how much faster I go. So im wondering if anyone has experinced any of these issues or has any idea of maybe something that could be shorted or damaged that would cause this as for changing the brakes and checking the fluid for the lights neither has fixed the lights and with oem rims and tires the lights still remain on. Other then that car makes great power runs smooth shifts fine just thinking something electronic is wrong.

 

I'd start by thoroughly cleaning up the grounding system throughout the car. Water corrosion causes a LOT of damage to them and the car is basically a giant sensitive computer.

ILSCO De-Ox and a wire brush will be your best friend.

Your nav probably is going out due to age, that's usually what happens when displays are about to go out. Speedometer you can plug in an OBD2 scanner and go for a drive to see if the computer is reporting the correct speed. If it's reporting it correctly then the instrument cluster (combination meter) is probably failing. If it's only reporting 60mph then it's probably an issue with the wheel speed sensors mounted on the rear differential. Very easy to replace those if they end up being the culprit.

 

I appreciate the feedback I have been brushing the engine bay grounds most of the day today which during inspection while swapping the block the engine harness semmed relatively clean and free of major corrosion I believe the problem lies in the interior but am unsure where exactly most of the ground points are but during a close look several connectors have green corrosion in them leading me to beleive the harness in the car may be failing. The speed sensor makes aense I beleive it would also potential cause the vdc abs and slip light issue as well. Im actually glad to hear that about the nav because I couldnt find any problems with the connections or anything in it when I had it apart. I appreciate the response any help is good at this point im more used to working on mitsu than infiniti/nissan so im a little lost with this car atm