So I was driving down the freeway today cruising at about 90 when my car downshifted to 4th for no reason, then shifted back up a few seconds later. When it did this, the RAS, service engine, slip, and VDC all came on and stayed on. ok well I already had VDC off while driving but the button became non-respnsive and the VDC was locked off.

I *think* the entire stability control was off. All other parts of the car worked fine and nothing seemed wrong except for the lights. During this time, the car shifted pretty much instantly, no delay of any kind when I mashed on the gas pedal. SO thats kinda cool to see I suppose. I was driving on side streets after the freeway and wanted to test if it was the stability control computer or not, so I floored it at a stop sign and had the tires spinning without the car trying to stop the spin at all so this also leads me to believe it is something with the stability control.

Does anyone know what could cause this? And how much it might be to fix it? If I have to replace the entire computer system ill probably just dump the car as it would be too expensive for me to fix. Especially since both the DVD player and CD Changer are both going bad already anyway. Im hoping it could be just some sensor though?

My 2007 M35x did the same thing back in June or July. Still have my warranty, took it to the dealer. They ran a diagnostic said it was a sensor error, they reset it and it hasn't happened since. Somebody told me it may be a sign the battery is dying, it's the original, 4 years old so it may be getting time to replace it.

Odly enough, I thought my battery might have something wrong with it just recently. It seemed like it has a bit of hesitation starting up lately, but the battery was just replaced less than 2 years ago. So maybe it has to do with that, I hope my alternator isnt going bad or something and causing the battery to not charge properly.

My buddy's '08 G did the same thing, I looked up on the G forum for him and found that with the Gs, that is a warning that the brake fluid is running low. He checked and he was low, topped it off and lights went out and haven't come back on since. Not sure if that's the same with the M's

Well, it happened again while I was driving to the dealership today. So I doubt its just a sensor malfunction that can be reset. I hope it something simple though, maybe like the brake fluid. lol Well see tomorrow... For now Im in a G25, its too slow

hope its somthin simple!

Just got a call about the problem, it is one of the overhead camshaft sensors going bad. So like your buddy had phillyM35, but mine has done it more than once now so resetting the error codes wouldnt fix anything, just cover up the problem. Costs $315 to fix. Not bad I suppose, considering what it could have been. I was preparing myself all morning for the news it was going to be a couple thousand to fix something either with the engine or the computer, all the while hoping it was going to be a simple sensor. Guess all that hoping and praying paid off

so it seems the best thing to do is to take it to the dealership and have them diagnose it to see which sensors are bad? if i took this approach, would that diagnosis be able to tell me if it's a bad battery, bad brakes, low brake fluids, etc? I know I'm able to check most of these things by just eying it (i.e. brake fluid) but all my fluid levels and car parts are running fine. I just dont want to pay for 50 checks, when only 1 check would have fixed my problem.

They would be able to diagnose whatever the problem is, Id guess though that in your situation it is not going to be something simple like low brake fluid. It is probably a sensor malfunction like some of us have had. That you would not be able to find yourself and a small time mechanic may not be able to catch it either unless he has the right electronic computer reading equipment for our car. He can probably pull an error code or two or three, but IDK if a small time mechanic without equipment designed to read our computer would be able to tell exactly which sensor is not performing properly. From what I have seen (may not be true) an error code is a bit more general like "hey the camshaft is not performing properly" or "a sensor in this section of the engine is not getting a proper signal". Thats why with things like this I always take it to the dealer to diagnose.

Riverside Infiniti has always been able to tell exactly what the problem is the first time through no matter how odd or complex the problem. They even helped another east coast dealer not long ago for one of the members here. That guy was given a big run around with all sorts of things and not able to find the issue, then Riverside Infiniti told the other place where to look and they found the problem right away and he got a whole new short block from it.

I'm actually going to try my luck with a small shop mechanic. When my car was still under Infinity warranty, I was shocked to see how much they were charging for (should I have been billed for it). That's why I am very hesitant to go straight to the dealership. I will definitly keep everyone posted in regards to what was wrong and if the small-shop mechanics were able to diagnose the problem.