interpreter

How do I replace a MAF sensor in 2001 S430? Is it a DIY job? Thanks in advance.

Skylaw

Welcome to the forum.

See post #36 in the the W220 S-Class Owners Start Here sticky at the top of the W220 forum. Download the pdf file (the "Encyclopedia), and look under the "Engine" heading. Save the pdf, and check for updates every so often.

It's a DIY and there is a link to it.

interpreter

Thank you for replying so quickly. I will check out the messages that you suggested and will follow the "engine" heading.
have a great holiday!

interpreter

Hi,
I did change the MAF sensor but the problem is that there was a plastic harness around the old MAF which the new MAF did not have (even though it is the genuine Borsch MAF and all the numbers on it are the same). When I tried to remove the harness in order to put it on the new MAF sensor I broke it. I still managed to put everything back the way it was supposed to be and it seems pretty steady and the car runs, but I am still uneasy about this plastic harness. Is it OK to use the MAF without it or should I go to the dealer and buy it?
Thank you in advance.

xexpo

I would buy a new one and replace it.

ohlord

like this it was an oem bosch maf and would have fit.
$146 free delivery www.autohausaz.com
if you bought it on ebay for less it won't matter if it had bosch numbers it is a fake clone and not worth the powder to blow it up.

interpreter

The MAF sensor fits perfectly (it is OEM item). I was saying that there was a sort of plastic ring around it which supports the sensor in place. It does not effect the performance of the sensor. I was only thinking that since there was this plastic support maybe I should buy and install it? But even without it the car runs perfectly. I still have the CEL on but I simply did not have time to have the codes erased. Will go to Autozone tomorrow morning.

ohlord

had the typical maf codes of p0170 and p0173
you won't need to erase the codes the light will go out on its own when the ecu adapts to the new maf.
Erasing the codes does not clear the issue if the issue is not truly remedied.
How many days since installed?

interpreter

Thank you for the advice. I replaced it just today (drove 15 miles home). How many miles do I need to drive before the CEL goes out?

ohlord

take several drive cycles. And they are sometimes a bit*h to achieve.
You could try a short cut idle adaptation and start the car in the morning and let it idle in park for 20 minutes(keep an eye on it, you don't want it stolen)
then just drive it like normal a few days cel should clear in that time or less.
Were the 70 and 73 the codes you pulled?

interpreter

I just came back from Autozone. They checked the code: PO410 - secondary air injection malfunction. So I guess I changed the MAF sensor for nothing. Will try to figure out what is wrong with the air injection system. Can be lots of stuff: Air pump, air pump relay, open or
short circuit condition, blocked hoses, etc. Will work slowly to eliminate one by one. Well, live and learn. At least I had the code erased (for now).

ohlord

to read codes first and post them here before tossing parts in
You can pick up a scanner for 70bucks or less on sale at harborfreight tools
item 94169 that way you have it handy. Reads clears reads I/M readiness and pending codes stored in the ecu.

On the secondary air it won't affect performance unless a broken vac line.
So inspect all vac hoses to the sec air pump.
Make sure the pump comes on when you start the car from cold in the morning.
Pump is black electric motor on the front of the engine when you pop off the engine cover and look at the top center front of engine.
Keep body parts clear of moving belt when examining things !!!!!

interpreter

You are absolutely right. I thought it was MAF since my mechanic mentioned it when looking at the code. I guess I should buy the scanner that you suggest and use it in the future. Meanwhile, I will check the sec air pump and hoses. Is it possible to check the pump during daytime or only when it is cold?

ohlord

when starting from cold and also runs the self test.
It injects air to fire up the cat converters quicker.
If it comes on then you know the pump motor is operating and that the issue is most likely a plugged valve or valves or a corroded reed valve.
How long has the light been on?
Do you live in a cold area and the light came on when the temp dropped?

interpreter

I live in NY. The problem developed about 2 weeks ago when it started to get a little colder. I will check the pump first. What is the location of valves and how many are there?
Now I have to run, so will post tomorrow. Thank you again.

ohlord

the two brass colored flattened canisters on either side of the pump.
If pump does not come on at start up cold check fuses and relay.
Don't have my w210 with me or I would check what # fuse. and relay.
If pump comes on you will need to inspect all vac lines to valves and pump
then if aok clean them with cleaner.
When you get back post what you discover
before cleaning the 2 valves ask what to use and how to clean them on this thread or pm me

interpreter

This morning I checked the pump and valves on a cold engine. The pump seems OK because you can feel suction of air when you disconnect hoses (black rubber tubes) leading from the pump to the valves. What was interesting, when I would disconnect one hose from either valve the motor would become real quiet, but when I reconnected the hose it became rough like a tractor. But after 30 seconds the pump switched off and the idle became normal sounding (no loud rough noise). The hoses also look OK. I noticed one interesting thing: near the right valve I saw a connector (like a plug) but the wire was very short and there are no other sockets or loose wires around it. Can it be for some diagnostic purposes (maybe there was a cap and now it is missing)? I am positive there is no place or wire to hook it up with. That is all I could find.