I drove home from work, and there were no problems. Next morning I turn the car on and have a "check engine" light on. The car drives normally, like before. I also have 'Service B 135 days ago' message on. Does that have anything to do with check engine?

What should I do? What can be the problem? Is it serious?

Car: 2002 C230k Sportcoupe

 

Get hold of an OBDII/CAN scanner & download codes. You will not know until you do this. Some auto parts stores will do this free if you don't want to buy one.

 

What is that? Where can I borrow scanner? Is that something I can do myself? Would my mechanic have that scanner?

 

Someone stole mine i think.. im so mad or i just miss placed it

 

http://www.harborfreight.com/cpi/cta...emnumber=98568

Then whatever code it tells you post it here and we will help you. Maybe an auto parts store might have and you can borrow it. I know Kragen use to lend tools but now they got bought out and policy changed.

 

My mechanic did it for free. It was 128 (or 138) and 141.
He said it was O2 sensors, and he shut the light off, he said if it repeats come back and clean it.

 

i googled it:
P0138 O2 Sensor Circuit High Voltage (Bank 1 Sensor 2)
P0141 O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)

 

The light came back on. Are those censors a serious problem? Is that something I can fix myself?

Car is a little bit more shake and jerky than usual, but not significantly.

 

If the car's not operating normally, why would you continue to drive it?

 

replace the front o2 sensor and you should be good.

 

+1 make sure you buy the genuine OE heated sensors. No generics even if they are Bosch. They don't work. This does not mean buying from a dealer. Shop around for the best price.

 

Thanx alot guys.

How do I know which one to buy? Is there a number, or do I have to pull it first?

 

Draze - You should have a M111 engine - yes?

If so P/N is 0015400517 for the upstream O2 sensor. Let me know if you need the downstream or if you have an M271 engine

 

I think I have M111. It's 2002 C230 kompressor soprstcoupe, 6 speed.
How do I know which one I need?

 

Yes, you have the M111. They've already said it's the upstream one you need and given you a part # - you're good to go on what you need.

 

I meant upstream or downstream? What is the price range?

Is that something I can do myself, or do I need to go to mechanic?

 

Yes, you can do it by yourself,
I can't find the right link for you
Try to search for O2 sensor

 

here is the link: https://mbworld.org/forums/c-class-w...placement.html , DIY: M271 O2 sensor replacement

 

would DIY for M271 be simmilar to M111

 

I would say yes, as long as all O2 sensors are the same, and I have done on my car too(2002 C230 coupe M111) so when you get under the car it's the same. You should look for a sensor that is located on the exhaust on the begining, it's next to the oil drain. But first of all take the plastic cover from the bottom off, if you wont you can take bouth of them off to chekc the status of your engine from underneath.
About the price: chek for oxigen sensor on the web, on specification you wiil find wich one you need.

 

Draze - sorry for the late reply - I started replying & my ADSL line went down yesterday - now back in action.

This can be a little confusing because Benz don't state which sensor is 1 & which is 2. Logic would dictate that 1 is the upstream sensor. The upstream O2 sensor (lambda sensor) feeds the ECU, along with the MAF - to ensure proper mixture control while the downstream sensor reads the effectiveness of the Cat at cleaning up the exhaust gas.

You are getting a sensor 2 reading but no cat code & if sensor 1 is the upstream unit you should throw a fuel trim code if it is defective but you are not.

At the age of your vehicle - you don't state mileage - I recommend you replace both sensors. O2 sensors have a very rough design life of approx 80,000 miles before they start cycling too slowly.

The downstream sensor P/N is 0015404717

 

P0138 O2 Sensor Circuit High Voltage (Bank 1 Sensor 2)
P0141 O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)

Does that message says sensor 2?
I'm at 210000km.

 

Yes - The message says sensor 2. At that mileage replace both. They are WAY over the hill.

 

Thanx, I will try to do so, but the sensors are pretty expensive.

 

Yeah I know - should improve your fuel consumption though. The joys of running a modern car. The good thing is that your Benz will do huge mileage.