As some of you know I bought my first W124 (E320) a few months ago. When I went to register it about 4 weeks ago, it didn't pass emissions probably because the fuel had sat with the car for too long when the seller had it on the market. It was almost empty anyway. So, I bought some 'guaranteed to pass' and put it with a full tank of premium fuel. I passed without issue. Shortly later, my 'check engine' light came on and I've been getting really crappy gas mileage since then (gone from about 21 to 16 approx).
I took it in the the local German repair shop today and the old German fellow said it sounded like it was a bad O2 censor (my thought initially). He said to bring it in on Monday and have it checked.
3 questions:
1. How expensive are O2 censors to replace? (ie how much is the actual part and how much should labor run)
2. Is this something I can DIY (if so, does anyone have instructions)?
3. Does it sound like an censor problem to you, or something totally different?
its a cheap part sort of, you can do it yourself if you know wat your dooing, but there can be alot of other variables. check the thodel body and even though in a bottle of Lucas fuel injector cleaner in there. that stuff cleans your entire fuel system and has worked many times for me. i use it 2wice a year for reg, maintenence.
Before you go throwing parts at the car, why don't you read the code?
On my car, it is VERY easy. Next to the battery, there's a rectangular plastic box. Remove the cover. With the ignition ON, push the button inside this box for 3 seconds and count the number of times the red LED flashes. Repeat this procedure until all codes are read (if it flashes 3 times, it means code #3).
Then let us know what codes we read or you can do a search on the archives to interpret these codes.
The O2 sensor should be cheap ($100-$150) and very easy to replace.
Before you go throwing parts at the car, why don't you read the code?
On my car, it is VERY easy. Next to the battery, there's a rectangular plastic box. Remove the cover. With the ignition ON, push the button inside this box for 3 seconds and count the number of times the red LED flashes. Repeat this procedure until all codes are read (if it flashes 3 times, it means code #3).
Then let us know what codes we read or you can do a search on the archives to interpret these codes.
The O2 sensor should be cheap ($100-$150) and very easy to replace.
Sergio
'95 E320 167K miles
Sergio do you know what code a bad O2 Sensor will throw out??
I did this coding check right now and after holding the button for 4 seconds I just get 1 blink , do you knwo what 1 is??
Thanks
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In the world of roads, there are those who travel and those who own it. The choice is yours.
i had a similar problem in my car. i was getting bad gas mileage and didn't know why. i figured out it was the o2 sensor. i paid around 150 and replaced it. my gas mileage went back to normal. i don't think my check engine light went on though. it was a while ago so i don't remember.
iv just bought some of the above mentioned lucas injector cleaner
i will post my results when i have some
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merc 300 ce, amg bodykit, 17" amg alloys, lowered, Azul Azurite blue 98000 on the clock and two tone leather!!! (click a picture to see a larger image)
I found this on a search " fault codes " / "check eng. light " It think it was Kestas's post
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Why don't you check which Code is set. The car has self-diagnostic ability with a built-in led/sw at the diagnostic plug for code retieval... you don't ground/jump anything... Turn on key and push button - hold for 3 secs, release and count the reply code flashes--- continue on until all are flashed and original repeats.
One flash is No Codes Stored.. [that will not be the case on yours as the CE is on, meaning a fault has been detected]
The system is next to the right corner of the battery. It's on the right-side firewall that separates the battery from the engine. It's a little black box with white numbers from 1 to 16.
On number two, there is a button. That is the button you press down and hold for 4 seconds.
To the right of this button is a a little round light. That is the LED that will flash.
This is the code list for an E320. I don't know how different it is for an E420:
Code List
1 No malfunction in system monitored
2 Heated O2 sensor inoperative
3 Lambda control inoperative
4 Air injection inoperative
5 Exhaust gas recirculation inoperative
6 Idle speed control inoperative
7 Ignition system defective
8 Engine coolant temp. sensor, open/short circuit
9 Intake air temp. sensor, open/short circuit
10 Voltage at hot wire mass air flow sensor too high/low
11 TN-signal (rpm) at engine control module (N3/4) defective
12 Heated O2 sensor heater, open/short circuit
15 Wide open throttle information defective
21 Bad Purge Switch-Over Valve
22 Cam posistion sens. signal defect
23 Intake man. pressure low
24 Starter ring gear segments defect
25 Knock sens
26 Upshift delay SOV (switchover) valve open/shorted
27 Deviation between coolant temp sensor circuits 1 &2
28 Coolant temp sens.
Linear Mode
