demfis

Dear all,

I have a 2007 SL550. Today the car won't change gears and the check engine light went off. Of course the car went out of warranty few weeks ago and today is a saturday. i am trying to figure out what can be causing this. Thanks.

Regards,
Demfis Fyssicopulos

mleskovar

Your car has gone into limp home mode. Get an OBD II tester ($40?) and check what code is causing the CEL (write all codes down for future reference). Clear it, and see if it comes back when you drive again.

demfis

Dear Sir, thank you VERY much for the reply. Where can I get a OBD tester?

mleskovar

Any auto parts store. Just make sure it can clear codes as well as read them. It plugs into a port usually underneath the dash around the steering column.

demfis

Thank you again. I just did the test and the result is P0178 - Pressure Control Solenoid Electrical. Clearing the error did not help. You seem quiet knowledgeable., would you have an insight of the severity of this repair?. Thanks again.

Regards,
df

mleskovar

I'm not familiar with that code, it appears to be something in the fuel pressure regulation from what I read. The codes can be generic, like a bad oxygen sensor, or specific for a manufacturer/model. To decipher a specific/non generic code you often need the right equipment like SDS (expensive). Anyone familiar with this code on an SL550?

demfis

We tried two different testers. The other tester (not specific for MB) gave a code of P2734 which had the same description - Pressure Control Solenoid Electrical.