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DIY Cleaning MAF sensor & Throttle Body
Thread Starter
Member
Joined: Nov 2011
Posts: 99
Likes: 4
From: Ann Arbor, MI
2008 c300 sport 4matic
DIY Cleaning MAF sensor & Throttle Body
This DIY guide will outline the steps I took to clean my MAF sensor and throttle body on my 2008 c300 sport 4matic m272 engine.
**As usual, this is for entertainment purposes only. I nor Mbworld.org are not responsible for any damage done to your own vehicle.
Tools:
Flat-head screwdriver
MAF sensor cleaner
Throttle Body cleaner (not carburetor cleaner)
Time to complete: Less than 1 Hour
1. Remove negative wire to battery terminal. Remove engine covers. The smaller one towards the front of the vehicle simply pops off. The second larger one requires you to wiggle the two big air hoses free. There is a small hose near the center of the engine cover that also must be removed. These all wiggle free, no removing of any clips or screws are necessary.
2. Locate the MAF. The MAF has a circular opening and is located in the center, closer towards the back (top) of the engine. It is impossible to miss, the engine cover seats flush with this opening when reinstalled.
3. Remove MAF sensor. There is one electrical connection. Push the grey holding clip back with a flat head screw driver, once it snaps back it's easy to remove. (This the the same type of electrical connection you will find all over the vehicle) There are three clips holding the MAF sensor in place. Image 1 shows the two plastic clips (in black), and Image 2 shows the third clip (after MAF is removed). The metal clips in the back must be pushed out of the way first (Image2). Simply use your finger, or flat head to push the clip towards the rear of the engine compartment. The clip will stay out of the way, but does not come completely out. In red (Image 1) shows the direction you must push the two black plastic clips - first outward, the backward (towards the back of the engine compartment). In Image 1, you can see I removed one clip first (right side of image), then the left side. I don't suggest trying them both at the same time.
4. Use an appropriate MAF sensor cleaner. Directions are on the bottle. Simply spray a handful of times. Make sure to spray the sensor (small, paperclip, thin metal type looking thing). The cleaner is quite volatile and evaporates quickly. Place sensor somewhere clean to dry.
5. Next we must remove the black plastic elbow. Image 2 shows what things will look like once the MAF sensor is removed. This elbow is not held in very hard at all. Two easy-to-remove black plastic clips hold this in place. One clips is on top, the other on the bottom. Bottom clip is accessible from the passanger side of the vehicle. There is also a rubber hose connected to this elbow, but it is flexible and doesn't need to be removed. I simply pushed the elbow to the passenger side of the engine compartment to access the throttle body (hose still attached).
6. Image 3 shows what things look like with the elbow removed. This image is looking directly down from above the engine. I did not remove the throttle body, you can clean this while it is still installed. Image 4 shows what the mouth and butterfly valve of the throttle body look like (dirty). This is what we will be cleaning. Use throttle body cleaner (not carburetor cleaner). I placed a rag underneath the throttle body opening just so any drippings would be caught. Spray and wipe down with clean rag until clean. You can manually open the butterfly valve by pushing on the bottom half of the valve. The valve will be flat once completely open. You must hold the valve open to clean, it will want to close on its own (not too much force is required to open the valve--you cannot push the top of the valve to open, that's the wrong rotation)
7. Once everything is dry and clean simply reinstall in reverse order. There are no hiccups reinstalling. When reinstalling the MAF sensor I attached the metal clip first, then again, one at a time, slide the two black plastic clips in place. When reinstalling your engine cover, make sure its seated completely flush on the MAF sensor. You should NOT be able to wiggle your engine cover at all, it will be firmly in place when installed correctly. If this is not seated correctly, it could throw error codes.
8. Once finished, insert key and turn to position 2, do not start engine. You may hear your the actuator clicking and other electrical noises. Wait a few moments until the noises stop. This step may be unnecessary, but is to ensure the throttle body valve is correctly "re-calibrated".
*Note: In the event you do not install engine cover correctly, and you do get a CEL, simply remove the engine cover and reinstall correctly ensuring all hoses are correctly connected and CEL will remove on its own after enough miles/engine starts
Please don't hesitate to ask any questions. This is an easy and inexpensive project to accomplish. (Less than $20). First time you start your engine it may take one or two seconds longer to start and idle roughly for a few seconds. This is normal, the engine is simply processing the cleaner and will idle smoothly after a few moments.
**As usual, this is for entertainment purposes only. I nor Mbworld.org are not responsible for any damage done to your own vehicle.
Tools:
Flat-head screwdriver
MAF sensor cleaner
Throttle Body cleaner (not carburetor cleaner)
Time to complete: Less than 1 Hour
1. Remove negative wire to battery terminal. Remove engine covers. The smaller one towards the front of the vehicle simply pops off. The second larger one requires you to wiggle the two big air hoses free. There is a small hose near the center of the engine cover that also must be removed. These all wiggle free, no removing of any clips or screws are necessary.
2. Locate the MAF. The MAF has a circular opening and is located in the center, closer towards the back (top) of the engine. It is impossible to miss, the engine cover seats flush with this opening when reinstalled.
3. Remove MAF sensor. There is one electrical connection. Push the grey holding clip back with a flat head screw driver, once it snaps back it's easy to remove. (This the the same type of electrical connection you will find all over the vehicle) There are three clips holding the MAF sensor in place. Image 1 shows the two plastic clips (in black), and Image 2 shows the third clip (after MAF is removed). The metal clips in the back must be pushed out of the way first (Image2). Simply use your finger, or flat head to push the clip towards the rear of the engine compartment. The clip will stay out of the way, but does not come completely out. In red (Image 1) shows the direction you must push the two black plastic clips - first outward, the backward (towards the back of the engine compartment). In Image 1, you can see I removed one clip first (right side of image), then the left side. I don't suggest trying them both at the same time.
4. Use an appropriate MAF sensor cleaner. Directions are on the bottle. Simply spray a handful of times. Make sure to spray the sensor (small, paperclip, thin metal type looking thing). The cleaner is quite volatile and evaporates quickly. Place sensor somewhere clean to dry.
5. Next we must remove the black plastic elbow. Image 2 shows what things will look like once the MAF sensor is removed. This elbow is not held in very hard at all. Two easy-to-remove black plastic clips hold this in place. One clips is on top, the other on the bottom. Bottom clip is accessible from the passanger side of the vehicle. There is also a rubber hose connected to this elbow, but it is flexible and doesn't need to be removed. I simply pushed the elbow to the passenger side of the engine compartment to access the throttle body (hose still attached).
6. Image 3 shows what things look like with the elbow removed. This image is looking directly down from above the engine. I did not remove the throttle body, you can clean this while it is still installed. Image 4 shows what the mouth and butterfly valve of the throttle body look like (dirty). This is what we will be cleaning. Use throttle body cleaner (not carburetor cleaner). I placed a rag underneath the throttle body opening just so any drippings would be caught. Spray and wipe down with clean rag until clean. You can manually open the butterfly valve by pushing on the bottom half of the valve. The valve will be flat once completely open. You must hold the valve open to clean, it will want to close on its own (not too much force is required to open the valve--you cannot push the top of the valve to open, that's the wrong rotation)
7. Once everything is dry and clean simply reinstall in reverse order. There are no hiccups reinstalling. When reinstalling the MAF sensor I attached the metal clip first, then again, one at a time, slide the two black plastic clips in place. When reinstalling your engine cover, make sure its seated completely flush on the MAF sensor. You should NOT be able to wiggle your engine cover at all, it will be firmly in place when installed correctly. If this is not seated correctly, it could throw error codes.
8. Once finished, insert key and turn to position 2, do not start engine. You may hear your the actuator clicking and other electrical noises. Wait a few moments until the noises stop. This step may be unnecessary, but is to ensure the throttle body valve is correctly "re-calibrated".
*Note: In the event you do not install engine cover correctly, and you do get a CEL, simply remove the engine cover and reinstall correctly ensuring all hoses are correctly connected and CEL will remove on its own after enough miles/engine starts
Please don't hesitate to ask any questions. This is an easy and inexpensive project to accomplish. (Less than $20). First time you start your engine it may take one or two seconds longer to start and idle roughly for a few seconds. This is normal, the engine is simply processing the cleaner and will idle smoothly after a few moments.
Last edited by tpdietz; Mar 12, 2013 at 05:47 PM.
Super Member
Joined: Oct 2014
Posts: 701
Likes: 103
From: Ontario, Canada
2009 C63 AMG, 2010 C250 4Matic Sport
Thanks for this guide.
As an FIY to anyone else having issues with rough idling at a stoplight, this may be your answer. I did both the MAF and throttle body at the same time obviously. Engine seems to be running much more smoothly now!
As an FIY to anyone else having issues with rough idling at a stoplight, this may be your answer. I did both the MAF and throttle body at the same time obviously. Engine seems to be running much more smoothly now!
