THROTTLE POSITION CODES

[wklovell]

Took my G37 in yesterday because it was sputtering and the SES light came on. If I turn it off and on like 4 times it will run fine...........The dealer said that "Throttle position codes found due to malfunctioning T-bodys." It runs fine for a day or so and then does it again.

Well, to replace both Throttle bodies is $1766.00!! How can the throttle bodies be bad when there is only 22,500 on the car??

Which throttle position codes say that the throttle bodies are bad - there are many of them? And BOTH T-bodies are bad?

Please help.

Love the Car - when it isn't sputtering!!

[Poyzinous]

That should be warranty work. And I've yet to see throttle bodies fail on the V36 models. It may be you have that one in a million issue. However, the Throttle bodies ARE expensive. I still think thats a warranty issue though. More than likely only one is bad, that or there is another fault triggering the issue, but I dont know what else besides the MAF sensor.

[SteveTheTech]

Welcome to Nico wklovell,

As Poyzinous mentioned this type of repair should be covered under powertrain warranty. If you have no basic warranty is there a reason? Is there some reason the electrical wiring harness may be damaged?

If you are still under warranty and depending on the code numbers I would look closely at the accelerator pedal. It is extremely rare that both throttles would require replacement.

[wklovell]

Thanks guys for your help. The car had minimal damage near the front left headlight/fender when someone else owned it. The insurance company wrote it off as a total loss, it was fixed beautifully and I got a GREAT deal. But, as you probably know, I don't have a warranty because of it. I'm OK with that because I got such a great deal. I love the car and plan on keeping it a long time!

I took it to our Infinity dealer and because it has a rebuilt title they just automatically snubbed me and just blamed the way it was running on the fact that it was in an accident. I've driven it a few thousand miles with zero problems though. My wife's family is in the business of restoring cars so we know we got a good deal. It is just unfortunate that instead of treating me like I am someone with a legitimate complaint that needs service and they want to fix it for me, they act as if they are too good for me. And, I don't mind paying for it either. You would think they would want to keep my business instead of making me feel that I have a crappy car. Anyway..........that is why I need help diagnosing and also just because I want to learn everything I can about the car. Its kind of like when someone insults your kid, it really bothers you, but in this case it is my car!

When you push the button to start the engine, it turns over and starts. The tach appears as if it is idling fine. When you try to push the throttle and give it some gas, the tach drops and it sounds like it is coughing. It seems to sound or act as if it is trying to "flood" like back in the carburetor days. From the time I started it, ALL the warning lights stayed lit.

After it did this I turned it off. I tried to restart. This time it acted basically the same way, but only the VBS and SES lights stayed on. I turned the car off again.

I started it a third time, it is still running bad, but only the SES light stayed on. I turned it off.

I started it the fourth time, SES stays lit, but the car coughs a bit and then starts running normally.

It ran fine for about 10 start-ups, took it to dealer, they reset codes and told me both throttle bodies were bad because the TP sensors came on. I didn't have them fix it because it was really expensive (no warranty) and I wanted to make sure that was it before I spent that much. It was running fine, but did the coughing episode again two days later - the EXACT same thing with it taking four starts to get it back to "normal" again.

Any and all of your expertise is appreciated. I can ask them what specific codes, but I'm not sure they know since they are not on the computer print out either.

Thank you so much!Ken

[SteveTheTech]

Here is a link to the FSM, you will need to familiarize yourself with this. Repaired cars tend to exhibit some strange issues and many dealers do not want to commit their time or technicians to these projects. As long as the owner understands there is only so much we can do and all bets are off as it pertains to guaranteeing any repairs.

Personally I willingly take on projects like this they offer a break from the monotony that can occur at the dealer. If you go in there knowing and expecting to pay for their diagnosis I do not understand why they want nothing to do with you and shotgun two throttle bodies. I find that a little extreme.

[SteveTheTech]

The basic rule of thumb when starting with a random or CAN related issue with this type of car. Visually inspect every inch of the wiring harnesses to look for any damaged wires, missing grounds or "modified" connectors.

[wklovell]

Update and a new question on my strange starting behavior problem.

Its been a week since the last time it did its funky thing, and last night the SES light reset itself. I'm assuming that after a certain number of times that a problem doesn't show up, the ECU decides the car is happy again?

Also, local offered up the theory that it could be a bad mass air flow sensor. I know that without more infomation that is tough to pin down, but any ideas on that one?

Thanks,Ken

[wklovell]

OK, we are now no longer intermittent. Right after my last post, I walked out to the car and it did the same thing, but this time it did not resolve itself.

We also have some additional symptoms. The SES light is on - no surprise there. I also have a VDC light and slip light that come on at start, turn off like it is settling down and then come back on again and stay lit.

Also, the car will throttle up, but there is a huge hesitation before it goes. Its like a full second delay when I push the throttle before it jumps up. And when it comes down, there is a kind of "puff puff" exhaust note at the end.

When it starts, the tach jumps up above 1K then falls down between 500 and 750 and sputters for a second before catching and staying at around 1K. But all the lights stay on and it has the huge hesitation problem described above.

I haven't tried to move it yet, so I don't know what it will do under load.

Ideas?

[wklovell]

Problem is resolved. Turns out it was a broken connecting wire to the throttle body. Specifically, it was a the b-2 throttle chamber harness connector that was damaged and the wiring going from the connector was damaged also.

Found an honest tech in Hardeeville, South Carolina. He checked the thing over all the way, found the problem and gave the whole car a once over.

Can't recommend the guy enough. If you need something done and are in the area, go see Jay at Key Infiniti in Hardeeville, SC just outside Savannah, GA.

Nice to find honest people. Worth driving two hours to work with.

Thanks to all of you guys for helping think it through.

- Ken

[SteveTheTech]

That is great news,

Sorry I've been delinquent in replying.

I first saw that you drove to SC to get this resolve and was like , if that is what it takes to save yourself the money of two shotgunned throttles that would have had no resolution.

Since the CEL and VDC lights were on I would strongly have leaned toward either a signal or CAN line to one of them. The only way to narrow that down is to break out the trusty ole multimeter and have at it.

Again on the repair, if you ever have any other concerns or issues with your car email me if I miss the thread.