BenzWorld Junior Member
Date registered: Jan 2018
Vehicle: 99 E430, 08 E63 AMG
Location: Kamuela, Hawaii
Mentioned: 0 Post(s)
Quoted: 1 Post(s)
Fuel economy drops by 40%, CEL on
Sudden loss of fuel economy and CEL on. Hooked up the OBDII reader to discover code 0171 (bank 2). Bank running lean.
Researched to discover PROBABLE MAF sensor failure. Replacement part is available for about $200.
I didn't know how a MAF sensor worked, so began searches. During to search I discovered a post where it was explained that the sensor CAN get dirty, and it was suggested that a thorough cleaning would be the first step.
With a screwdriver, I gingerly removed the upper and lower clips that held the sensor in the airbox. I carefully withdrew the sensor then gave it a good spraying with MAF cleaner, then re-installed it. I cleared the DTC through my OBDII reader. I was concerned that there might be a little cleaner remaining inside the sensor, and considering there is a wire that heats up contained within the sensor, I gave it overnight to dry out, the cleaner being flammable.
Took the car for a 20 mile run. Fuel economy back up to >20 mpg.
Happy camper here.
Now I do understand that this might not be a long term fix, that the problem could return. If that happens I'll replace the sensor at that time.