I'm in need of some help...my wifes 04 G sedan has gone into limp mode. I am a do it your self kind of guy, but not so much with the these fancy new cars.

The codes I'm getting on my scanner are P2128 (Pedal Pos Validation switch 2Hi) and P2138 (Throttle Pedal Pos Sens/Switch D/E voltage correlation)

The Service engine light is on, as well as the VDC off, Slip and AWD light. The car has no power to accelerate.

I tried clearing the codes with the scanner but they came back right away.

I've googled the net several times over and have found people with a similar problem, but no one ever posts how they fixed it or what was wrong.

Can anyone help??

I've heard 2 suggestions, replace the TPS and or replace the gas pedal sensor/switch....


Help...I can't afford the $500 to $1000 bill at the stealership to get this fixed! Any help greatly appreciated and I promise to post what the problem turned out to be in the end.

 

update:

I managed to reset all the lights and codes by disconnecting the battery and doing the key on/off thing. The car idles fine, and I backed it out of the drive way at idle speed, put it in drive and moved about a car length with my foot on the gas when the car sort of stalled, the VDC off light, SLIP light and SES light came on. I pushed the pedal to the floor and the car barely moved forward.

Went round the block and repeatedly mashing the pedal to the floor made the car go a bit quicker on accelleration, but still very unresponsive.

Back in the driveway I did the key on/key off thing again and it reset the lights (minus the SES light) and the car started up and ran good. I put it in drive and one foot on the brake the other on the gas and boom the lights came back on.

I've read through the service manual i found online, and I'm thinking the Accellerator Pedal Position sensor is bad

Anyone?

 

Might wanna post this down in the tech section shaun. Im sure someone down there can help ya out.

 

probably needs a throttle body.

 

Ordered a new APP sensor (gas pedal) and a throttle body today. Should be in on weds.

The dealership told me it would cost about $130 just for diagnostic, which is about the price of the throttle body...so I figure I'll just give it a whirl myself.

 

havent replaced any pedals on the v35s. however, I have done a few throttle bodies.

 

The dealership had throttle body's in stock, and had to order the pedal...so I was kinda thinking I'd start with the throttle body and go from there. Its also the cheaper of the 2 parts.

 

Here is what I found....

1. Replaced the throttle body, did all the resets/relearns in the shop manual, drove the car and the problem came back right away.

2. I then replaced the gas pedal with the accelerator positioning switch, did all the resets/relearns and poof, problem is gone.

So I spent $411 CDN on parts and fixed the problem, versus paying the delership $130 to diagnose, $$ for the part, and another $130 or more to install. If I had done the pedal first, it would have been half the price...oh well.

So with my codes the problem was the accelerator positioning switch, or a combination of.

Thanks to those that replied to my original post.

Cheers

 

I appriciate someone acctually coming back and saying how their problem was fixed! Props!!

 

I have the same problem.. TPS... maybe this is the cure for me as well..

 

no problem...everyone can offer advice, but often the results are the best indicator of the original problem and no one ever posts them because we all come to the forums for help in the first place and once the problem is fixed no one ever logs back in what happened.

Glad I could maybe help out.

No problems since replacing the pedle position sensor 3 months ago.

Cheers

 

Good job!

 

Hey did you replace the app switch yourself and if so how hard was it? I am having the same issues, p2128 and 2138! Cruise control set light started flashing then ses light, slip and vdc came on. Cleaned my tb about a month ago and haven't had any issues since I got my idle right. Both times it rained really hard when I've had issues with my car going into limp mode. Could it be the battery also I did have it checked and they said it was bad. Any advice would be appreciated....

 

Old thread revived! I replaced the switch myself. Couple of small bolts and a harness if i remember right. Took only a couple minutes. I have since sold this car long time ago and bought an Audi Q7.

Good luck!

 

2008 G35 p2127 and p2138 no throttle response.. new pedal and TPS sensor @throttle body.. HELP!