Hi everyone,
I have a 2005 G35 and as I was driving home, I suddenly lost power. I pulled to the side and turned off the engine. Then I started it back up and I had the check engine light, VDC, and slip lights on. The engine went into limp-mode and I had a long ride back home going like 5-10 mph max with no more than 1500 rpms.

I checked to see what was wrong with the car and got these 3 codes:

P2122 - accelerator pedal pisition sensor 1 circuit - low imput
P2138 - accelerator sensor circuit performance
P1229 - Sensor power supply circuit short

Thinking it was the accelerator pedal sensor, I went ahead and bought a new one. Installed it, did the Pedal Position Learning reset and still got the same results.

I have checked the continuity of all the wires in the APP sensor and all 6 of the wires from the sensor are fine. Then I did a voltage test on the sensor and got this: PIN 6 had 2.1v while PIN 4 had 4.46v.

Am I missing something here? Is there a relay or something that might have blown causing low voltage to one of the sensors?

This problem has been driving me crazy. The nearest dealer is quite a ways away so I can't just take the car to a dealer.

Any help would be greatly appreciated.

 

I have the same problem... You ever figure it out?

 

We have experienced this problem SEVERAL times, It is almost always a dead Throttle Body. It can also happen when voltage is very low (bad battery) but more than likely you need a new TB. It may start begin working but it will happen again and inevitably completely fail.

You can go by just about any Autoparts store and they can make sure its not just the battery.

If you need to order a TB feel free to give us a call or PM me.

-Rob

 

^^^ what he said as im on my 3rd one.

 

Actually no! Throttle body is not only the problem!
Actually it was no where near the throttle body.
Here's what I did. I got a voltage checker and did a test of every single sensor that was affected and trust me P1229 Power Supply runs a bunch of sensors...

After many hours of testing i discovered my problem. There was a short in the one of the sensors... Had to get it replaced and reset. I don't know what the two APP sensors were all about... The APP was working perfectly fine... That's what threw me off...

But yeah a lot of continuity testing and voltage testing got me to the right place.

 

Yaro - great description. So interesting add:

Last night I had the identical conditions to Yaro's problems. VDC OFF, SLIP, and SES indications; negative throttle response. I left the car parked where it was, and got a ride home. This morning I went to grab my car... VDC OFF & SLIP indications were GONE! SES remains; but throttle response was normal (I didn't try pushing it).

I've driven it to a friend's so he can pull the codes for me. Any advice on trouble shooting?

Yaro - you said you found a shorted sensor. Which one did it end up being?

 

A couple weeks ago my G35 6MT died at a stop sign. Felt like it had stalled out but when I went to turn it on the "check engine light" light was on. It also said "slip". Would only start randomly and idle was unusually low. The car will die while I'm driving, but more often when I depress the clutch or stop. The code read p2138, so I bought a new Pedal Position sensor and had it installed. Car ran well for about five minutes and then died again. Code still says P2138 Throttle/Pedal Positions/ Sensor/ Switch "D"/ "E" voltage", Correlation... mechanics have no idea what it is. Any ideas???

 

Hey ajaffe8...

I'm glad you posted this, b/c I ended up figuring out my problem but never posted. I ended up flooding my fusebox. No joke, it had been raining and I had driven through a puddle so forcibly (and/or my fusebox is not sealed properly) that it was filled with water. In April (when I wrote the previous post), I did not realize this... the fusebox had drained and the car started that 2nd day.

However, at the end of 2012, the same problem happened. This time I used my truck to tow my car to my house. While investigating the issue, I pulled my fusebox open and a significant amount of water came out. I pat-dried it with towels and waited till the next day to crank the motor. It worked perfectly.

Best of luck!

 

Replaced my pedal position sensor, checked for water or moisture and there is no sign of any. The car was running fine for about two weeks with me clearing the code when it appeared however now I can't make it past three or four lights before the car dies. Any cheap way to check for shorts? I need to go another 600 miles before my warranty kicks in.

 

which sensor had the short???!!!