DetroitAllroad

Last time I drove to work in the rain I got three dash lights. ABS EPC and ESP. I pulled off the highway and turned the car off, then they went away.

Its been a few weeks now since this happened, and today after getting out of the car wash I got the same lights and lost a ton of engine power. This time it also threw a fault code P2138 for TPS/Pedal Position Sensor/Switch D/E Voltage Correlation.

Does anyone know what this means or what causing it? It seems to happen every time there's a considerable amount of water on the car.
Thanks, I appreciate any help.

John535is

There is a switch on the brake pedal.
When it starts giving false readings you get the 3 light combination ABS, EPC & ESP.
You will probably find you have no rear brake lights either.

The good news is they are only about $15 to replace from your preferred supplier and double that from the dealer. I think mine was P/N 1K2945511 but there are different part numbers for pre and post 2002.

There is a small 'trick' to installing the switch. Remove the panel in the footwell where the brake pedal is. On top of the brake pedal lever you will see the switch which you twist 90 degrees to remove (no tools). When you get the new switch, don't be compelled to play with it and push the trigger in, there is a small cam inside and it will reset itself to a high setting. Just leave the trigger at it's full extent, push the brake lever down away from the switch trigger so you can install it and twist 90 degrees without it contacting the brake lever. Release the brake pedal gently and it will locate against the plastic trigger on the switch and the internal cam will take up the correct height. Plenty of people brake the brand new switch by just trying to jam it in with the brake pedal in its full extension and the little plastic trigger snaps off or gets pushed in so far it does not contact the brake lever properly.

Otherwise it's a 10 minute job with no special tools. I found the new switch was a lot stronger looking than the one I removed which was pleasing to see.

I did not experience the loss of power and was not due to water. I have heard of some AR's go to 'limp' mode when this fault occurred, which could explain the loss of power you experienced.
You may have a second issue causing an electrical fault when it rains. I would replace the switch and look at the rear brake lights are not getting water in them.

Kneale Brownson

Since this is moisture related, I'd guess the brake switch is OK (unless you got water in the driver footwell) and the problem is corrosion on the wiring of the ESP module in the passenger footwell, below the opening from the cabin air filter.