cyaford

I'm hoping this helps someone else who has a similar issue:

Last Saturday, I was out for a joy ride. I briefly toyed with a C6 before realizing that my car had almost no power. I got off the interstate and then found out that the car would barely pull away from a stop. Fully floored, it took about 3 seconds for the tires to even start moving. Even then, it was slower than any modern day production car. Heading back home, I thought the car would return to normal soon. Nope, so I pulled into a parking lot and restarted the car. Everything went back to normal. About 1/4 mi away from the house, I went WOT to see if it was just a hiccup. Same thing as before. Limp home mode. After researching on this forum, and emailing a few members, all fingers pointed to a faulty IC pump. That was my bet, as I recalled reading several posts here about the SL55 falling on it's face from a bad IC pump. I was then pissed at Bosch, since I recently (2 months ago) had their updated IC pump installed to prevent this issue. Later that night, I bought a cheap OBD 2 reader from Amazon for $20. On Tuesday, I found code P0123. When I searched for that code, I then realized that it was not the IC pump, but rather the pedal position sensor. Since I didn't want to wait any further, I paid the dealer markup for the part and installed it the same day. BINGO! No more code and FULL power again. I took a few pictures of the install, but I doubt anyone needs them. I have the bare minimum of tools and it took me 15 minutes from start to finish, mainly because I was looking for a 10mm socket and taking pics. It's probably a true 5 minute job.

So, it sounds like 95% of the time this issue happens, it will be due to a faulty IC pump. Hopefully this post will save someone the headache of buying and installing a new IC pump only to discover the problem is still there. I could be wrong, but I'm guessing with a faulty IC pump the car will get power back after the supercharger temp drops from driving around. With a bad pedal position sensor, the only way to get power back is to restart the car. I'm sure there's more issues that could cause a similar situation, but now you have a good starting point.....

WHTEVO

Good post.

cal1

Thanks for the info. Since my SL has experienced just about every malady known to the R230 except for this one, I just might pick up a sensor and toss it in the trunk. I am sure it is just a matter of time before mine craps out.

Because our cars are "throttle by wire" and no throttle cable, they have a number of safeties built in. The throttle body also has a positioning sensor and the ECU compares the throttle pedal position to the throttle body position. If anything is out of whack, it is no go. My 80 mm TB sucked a gasket once. The throttle could not completely close so on startup, I got red ESP warnings on the MFD. The car would not move. Once we got the gasket out, everything went back to normal.

As far as a bad IC pump shutting down the SC, you are exactly correct. The car will feel like a dog, but you could still walk a Prius . I recall reading the HP drops to around 300 when the SC is down.

hopefully you will see that C6 again.

cyaford

Mine has 48k miles. The sensor is actually built into the gas pedal. Dealer price is $310, although online prices are around $80 cheaper. The good news is that you only need a 10mm socket to remove/replace the pedal, along with disconnecting/reconnecting the wiring harness.... A Prius would've walked me BAD that day. Thats how lousy the power was. lol