MAS replacement - PeachParts Mercedes-Benz Forum

richunters · #1 03-04-2003, 05:03 PM

In another thread I talked about how my Check Engine Electronics light came on several times. I took the advice offerred here to change my gas cap, and took it to Autozone to have the OBD2 code read. The code was P0100, and Autozone printed out the following for me : " The PCH has determined that a malfunction exist in the electrical circuit for the Mass air flow or volume air flow sensor. This code points to possible wiring problem, ie, short to ground, short to power, or an open circuit"

Do I need to replace the MAS? Is this a easy do-it-yourself job with no special tools or procedures to follow?

mbdoc · #2 03-04-2003, 05:18 PM

Yes the air mass sensor is defective. Common fault, MB part number is 000-094-12-48 & list price is $ 240. OF course that is for your 1998 E300DT!

richunters · #3 03-04-2003, 05:54 PM

Wow that was a quick response MBDoc. yes, that was for my 98 E300d. I just called one local MB dealer and they quoted $319 ! What is your source and is it oem?

Do I need to have special eqipment or follow special procedures to install? Thanks in advance

#4 03-05-2003, 08:35 AM

Unless cash is no issue with you, I would strongly suggest checking the circuitry and functionality of the unit before buying a new one. Really easy to do with a volt meter.

richunters · #5 03-05-2003, 11:38 AM

Inspector are you suggesting there's an easy way to test the MAS to make sure it is not working? How do I check using voltmeter, is there a post you can refer me to? Thanks

#6 03-05-2003, 11:52 AM

This is a silly question, but to be sure, I'm guessing that this is the 98?

CarolinaMBZ · #7 03-05-2003, 12:18 PM

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diesel1mercedes · #8 03-05-2003, 12:36 PM

hi i can get you a new one for 200 dollars

richunters · #9 03-05-2003, 04:12 PM

CarolinaMBZ and Diesel1M : I am definitely buying from Fastlane.
Inspector : yes, for my 98 E300D.

richunters · #10 03-06-2003, 07:01 PM

Well I got the part and installed the new MAS.
The MAS unit (122) is bolted onto the intake air filter cover on one end, and connects to the hose (127) going into the intake manifold on the other end.

A simple job: Pull out the electrical connector. Loosen the screw on the o-ring clamp (133). Open the air filter cover so you can twist the cover/MAS unit away from the hose. Remove the 2 screws holding the MAS to the Air filter cover, then pull MAS off. Remove, clean, and re-insert the the rubber seal ring (114) on to the air filter cover. Screw on new MAS. Insert open end of MAS into hose. Replace and clamp down the Air Filter Cover. Tighten the o-ring clamp to secure the connection to the hose. Re-connect the electrical connector. A 10 minute job done in 20 minutes.

Rather than waiting for the Check Engine light to reset (which probably takes a week) I drove to the local Autozone to have them Read and Erase the OBD2 code. The guy there knew only how to Read the code, so he thanked me for teaching him how to Erase. Heck, all I did was pointing out the Erase button on his tool!

I hope the attached image makes it clear to newbies like me DIY for the first time.

pesuazo · #11 03-06-2003, 07:20 PM

I just wished the price and installation was the same for my car.
We have to buy the whole intake unit.