So I'm having an issue with my g35 every couple of times I drive it.

Today for instance, I was driving on the highway and all of a sudden the car stopped accelerating and then seemed to shift hard. When that happened, my Slip and VDC Off lights came on and I was then able to accelerate again. These lights have been going on and off like this for the past week.

Here's a little quick history on my car and maybe this will help:

It's approaching 131k miles and sometime in the summer, my Service Engine Soon light went off. I didn't notice any driving issues with the car, but I took it to autozone and got a P0327 code - knock sensor. Not long after that, the light went off so I thought nothing of it, and I did not come across this issue again up until recently. I'll get to that in a second....

I live in Michigan and it's now winter where it can get cold as hell. When the cold hits and I get up in the morning to warm up my car for work, it would hesitate to turn over. After a couple of cranks, it would then fully turn and everything would be okay, but I still had a SES light come up. The car wouldn't have a problem turning over if the engine was still warm (like after going to get groceries for a few minutes or something)....anyway, I researched this issue and found out that this can be due to a faulty camshaft sensor and/or crankshaft sensor. With that said, I bought all 3 sensors and changed them on my own (saved hundreds by doing this from what I understood!). The car had no problem turning over since I changed them, even in freezing whether...I figured that the issue was resolved, but noticed the the RPMs were jumpy upon acceleration, deceleration, and breaking. I will add that while I replaced the sensors, I cleaned out the throttle body as well.

After changing the sensors out and cleaning the throttle body, I reset the lights and they stayed out for around 20 miles or so, then the SES light came back on. I took the car back to Autozone to get checked and two codes came up:

P0327 - Knock sensor circuit low input - bank 1 (again - this might have been the issue all along since I never checked it when the SES light came back at the beginning of the cold).....It gave a few probable causes, but to play it safe, I ordered a knock sensor and knock sensor harness and will have them changed on Friday or Saturday when I get my intake manifold gasket to replace since the intake plenum must be removed to do this.

The second code was P0507 - Idle speed control system RPM higher than expected... It also gave a few probable causes, one of them being throttle body damage and the only thing I think it can be from regarding the throttle body, is a bad gasket since I opened it up to give it a good clean with the cleaner. I plan on adding a throttle body spacer in the coming month, and I hope it solves that code issue....but my RPM is still jumping a bit.

Getting back to the VDC and Slip lights that has recently been an problem for me....this issue typically comes up if I drive somewhere, make a stop and then start the car again a few minutes later. When I do crank it at that point, it hesitates to turn and I have to give it a little gas to get it to fully fire. It doesn't hesitate to turn over like it did prior to changing the sensors - it's a different type of hesitation this time around. After getting the car to turn over when it hesitates to, the Slip and VDC Off lights will stay on.

The lights will not come on and the car will turn normally if the car hasn't ran for a half hour or so. Just like today though, even when the lights didn't come on and the car turned normally, they eventually came on while I was driving. This is odd to me.

I'm hoping that when I change out the knock sensor and harness that this will help resolve the issue. I would attempt to do this myself as there are good directions on DIY replacements, but it's too cold outside here and I don't have a garage to work out of.

Sorry for rambling on, but many of you seem to know what you're talking about and I want to paint as many clear pictures for you guys as I can to help you better understand what I am dealing with. I fear that I can be making my car worse, but Friday is pay day and I'm still waiting for a part to come in before I take it to my mechanic...

Any information helps and I am grateful. Thanks!

 

My car was doin some pretty weird stuff when my alternator was dying.
Does your ebrake light also come on? That would indicate low voltage.

If your battery is low, your car will not drive. The transmission will go into limp mode. My new battery lasted a week then it was alternator time. What a pain in the rear that was....

 

Thanks for the response.

My battery is probably just north of a year old, and upon taking the car to get the code checked at autozone, it made no mention of any alternator issues. All the electrical works fine, even when the car stopped accelerating and hard shifted, prompting the VDC and Slip lights to go off.

Would the code reader notify you of a possible shitty alternator?

 

I dont believe the alt throws a code. At least mine didnt. It just died.

Best bet is check the voltage. Should be over 14v

Mine was about 14.2 v but it still intermittently would not charge for a few weeks. Then it just died for good.

The new/used one from an 06 is chargin at 14.6

I may be chasin ghosts here but you might as well check the easiest/not to obvious first. Sometimes a bad ground can mess things up.

Good luck

 

Thanks for that, I will definitely give that a look. I think all of these problems stemmed from a flood we had over here back in the summer time. I was trying to get home and we got hit with the worst flood we had in years. Fortunately, my car was a soldier and was able to drive through the waters while I witnessed pickup trucks and SUVS get their engines flooded and die. Some water got into the back of my car and I had to get it the carpet and padding drained and deodorized, my radio was a little shot (still goes out for a second every now and again) and the horn was flooded but dried out....I'm assuming in the midst of all of that, some components got jacked up...maybe starting with the sensors, and then the knock sensor and yada yada...

So when you say check the voltage of the alternator, how do I do that? I'm sure I can find a youtube video. Thanks again!

 

Alternator checked out good....got the proper readings, I also did all reset procedures for my CEL and I'm sure it will illuminate again, but hopefully the throttle body and RPMs are handled.

 

Hey man, My car's vdc and brake and slip lights also came on a couple of weeks ago and it turned out I needed brakes all around. Just a thought.

 

Just to be safe I topped off my brake fluid and took a look at my pads and rotors....they got at least a couple or months left on them....if I change out the pads before they get horrible, I'll be able to probably keep my rotors. Plus I am not hearing snd screeching sounds or grinding as I break which are typical signs that they need to be changed.

I actually had my knock sensor changed and I changed my cam sesnor again. The mechanic reset my codes and now I havent had any issues for about a hundred miles or so, lets hope it stays that way!

Thanks for the input!

 

My car has the same issue the vdc &slip light comes on the accelerator won't work and if you turn of the engine the car won't start for maybe 5 time trying and if you try to but on the drive mode the engine goes off and fuel smell is there please anyone can advice i have change recently the camshaft sensor bank(a) .please help .its g35 2007 sedan .