Members....

Requesting feedback on a relative recent experience of the fuel cap red dash light illuminating which initially occurred last summer. My fix was to stop the benz and recheck the cap, start the engine and there would be no other concerns. This same concern occured twice this summer 06 in which I was unable to access the emergency lane and/or get to the side of the road due to intense traffic and subsequently had the CEL come on. Read through the owners manual in how to proceed which there were no positive results for this issue. Also noticed in the odometer, malfunction message had caputured one malfunction. Had benz scanned @ a local autozone which revealed a P0455 code which indicates Emissions Eveporative System detected a gross leak ,and cleared code. Proceeded in my travel of more than 300 miles and within 25 miles on a 90 plus day, the dash indicator red flash illuminated and indicated coolant system and to have serviced @ workshop and also stored this code. No other concerns were indicated for remainder of trip.

Upon return home scanned using pernal tool and benz maintained the P0455 code. Conatcted Mercedes and it was suggested to check gas cap and i explained these procedures had been performed including a scan with the above code and coolant concern. My service advisor replied there is no scantool out there capable of diagnosing/scanning your car. Informed them that I would clear the code and to reflect concern in my service records. Recently within 2 weeks same code reappeared. I did not clear code and contacted my advisor and scheduled an appointment and had service performed yesterday. It was determined it was code P0455 with a purge valve concerns all SDS diagnostic test were done and new software was installed. My question is my advisor related to me not use my scantool because it will disorient the benz software creating problems and just bring benz back as it is still under warranty. However, once you are out of warranty to use my scanntool.

 

I don't know what anyone else would say, but if your car is still under warranty, you should just use the scan tool to read the DTC's and not clear anything. This way, you can determine if it's OK to still drive the car until you can get it in for repairs. For example, if you were getting a ton of P030x DTC's which is for misfiring in cylinder "x", you would probably not want to drive the car as there's a chance that raw gas is entering your catalytic converter -- replacing one of those is big bucks. You would want to DTCs to stay in the system for the dealer to diagnose/fix the problem. The SDS that MB uses provides more detail of the malfunctioning subsystem so the faulty component can be identified.

Hope this helps.

Regards,
paul....

 

What does SDS and DTC stand for?

 

Sorry......

SDS = Star Diagnostics System. This is the computer that MB service hooks up to your car for troubleshooting problems. These are very expensive units and the software needs to updated periodically. Some people have bought the cables and software on eBay and converted their laptop. I haven't heard what the success rate is on trying to do this, though.

DTC = Diagnostic Trouble Code. These are the codes you check to see when your Check Engine Light (CEL) comes on. These codes are part of the On-Board Diagnostics generation 2 (OBD-II) that's in all cars sold in the US from 1996+. The common DTC's are the powertrain/engine management system codes which start off with P0xxx or P1xxx. The P0xxx is a generic code standardized by the SAE (Society of Auto Engineers), and the P1xxx codes are manufacturer specific. If you do a google serch on "DTC" you can find a bunch of info telling you about all the "P0xxx" DTC's.

You can buy OBD-II readers/scanners and they come either in a handheld or a small unit that hooks up to your laptop with seperate software. These both have their advantages/disadvantages. IF you're looking to buy one, buy a scanner and not a reader, and make sure the scanner can read the CAN protocol. CAN = Controller Area Network.

Regards,
paul...