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Jay
Jay, Nissan Technician
Category: Nissan
Satisfied Customers: 19659
Experience:  20+yrs experience with Nissan & Infiniti Trained & Certified.Currently still working for Dealer
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I own a 2006 maxima 3.5 sl, the car is in "limp mode". The

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I own a 2006 maxima 3.5 sl, the car is in "limp mode". The TCS OFF and SLIP lights come on together with the SES light. I have noticed that this happens when its raining outside.Here's the codes in order displayed:P0451
P2138
P0643Do I have a short or do I need to replace APP sensor? I will need your help guiding me through the process of troubleshooting and replacing APP sensor if necessary. The fact that this only happens when it's raining makes this a curious problem.Thanks!

Hello my name is ***** ***** thank you for your question.

Does the radiator fans come on as soon as the ignition is turned on?

Customer: replied 1 month ago.
No sir.

Give me a few to review all these codes.. I have some thoughts.. but would like to review this before I say my thoughts.. Hang on please...

The P0451 is a Evap pressure sensor code. The Evap pressure sensor shares a 5 volt reference with the APP sensor. Try unplugging the Evap pressure sensor and see if throttle operation returns.

That could also be causing the APP sensor code as well...

and the P643 for power supply for App sensor..

Do you know where this sensor is located?

Customer: replied 1 month ago.
Take a look at this photo of wiring attached to Accelerator pedal. Looks like electrical tape is wrapped around bundle of wires. Could this come factory with tape wrapped around wires, or do you think this is suspect.I bought this car used ~3 years ago.BTW, I don't know where evap sensor is located. I'll ask google, but maybe you can help me locate.

That is the APP sensor.. Do not touch that. Start with the Evap pressure sensor. That is located on the Evap canister which is in the center of the rear of the car. Right above the sub frame.

That could be factory

The tape..

App sensors I don't see go often. Most cases the AC pressure sensor or the Evap pressure sensor which shares the APP 5 volt reference causing the App codes and throttle issues.

Since you have a Evap Pressure sensor code, that is where I would start. It mounts up high on the canister, above the vent control valve.

Customer: replied 1 month ago.
As you could imagine, I don't have a full blown garage with lift.I just got the car up on a jack stand. I got a look around and now equipped with your photo. I hope I can find and release sensor. I will report back shortly.

Sure take your time. You may need to lower the rear sway bar to get your hand up there..

If I remember right..

Customer: replied 1 month ago.
Alright. I unplugged it. It's a light gray harness that gave me a fit pulling it out. I may have even damaged the piece it plugs in to as it seemed to wiggle out a bit.Result... still "SLIP", "TCS" and "SES" light on.
Customer: replied 1 month ago.
Should I try to get a multimeter under there?

The codes wont' clear.. But take it for a ride and see if throttle response returned..

Customer: replied 1 month ago.
It's still in limp mode. Going for a ride is out of the question.

Then tests need to be done to see if your getting the 5 volt reference at the APP sensor.

Are you sure you unplugged the Evap pressure sensor? There is vent control valve back there also that is on the canister.

It should be a 3 wire connector at the evap pressure sensor. The vent control valve is only a 2 wire connector.

Customer: replied 1 month ago.
I just confirmed it's the 3 wire that's unplugged.Where should I test APP sensor?
Customer: replied 1 month ago.
Leave evap sensor unplugged?

Yes.. Leave it unplugged for now.. Do you have a volt meter and can you follow diagnostic steps?

Customer: replied 1 month ago.
It's a low-end model from Radio Shack, but it seems to be pretty accurate.

Give me a few and I will put together all the diagnostic steps for the codes you have.. Hang on please.. Give me a few..

https://www.dropbox.com/s/e12voctrepv203m/ECMAX.pdf?dl=0

I put all the Idle relearn steps on the last page of the info.

That is all the diagnostic steps for all 3 codes you have...

If you have any more questions on this, please feel free to ask.

If not, and you're satisfied with my help, please Rate me. That is how I get credit for my work. I hope I have provided you with Excellent Service.

Thanks Jay!

Customer: replied 1 month ago.
When they say instrument panel... where exactly are they talking about? Behind gauges or console (ac/radio)?see attached

That means with Dash removed.

Do you have any more questions on this?

Jay and 2 other Nissan Specialists are ready to help you