I've had the dreaded CEL for a couple of years. Coded P0170.

I cleaned the MAS with MAS cleaner, the EGR tube, later replaced the OEM MAS sensor with a knock-off. (then did a total Topend rebuild last year and replaced EGR tube, vacuum tubes, ...)

The P0170 and CEL are back. My independent has given it a few shots but comes back with explaining fuel blends...

I'm about the pull the trigger on a new OEM Bosch MAS 0280217500. I found for $160 on Amazon vs $300+ at stealership and $200 at most online sites.

Any other suggestions?

Thanks in advance!

CigarXO

I think "P0170" refers to the fuel trim or something related to the fuel/air mixture saved in the ECU memory..!,,

maybe ECU catch something wrong with fuel>>air>>O2 sensors..?!!?

,,ZAYED,,

P0170 Fuel Trim Malfunction. Check link below for some info and explaination:

http://www.autocodes.com/p0170_mercedes-benz.html

Zayed & DRB...
Thanks for the replies. Having experienced this CEL and Code before, I've climbed the threads and found they almost always point back to the Mass Airflow Sensor. The other causes mentioned in the link usually also send another code or indication on the reader - O2 sensor, etc. I think I'm just going to have to replace the MAS with OEM quality part and see if that gets rid of it.

Highly recommend you get a genuine Bosch MAF, despite the price. Getting the cheapo ones, you'll pay just as much as a Bosch after you have changed once or twice the crappy imitations. The MAF will die much sooner than other parts of the engine, so guess you have to live with this and replace when necessary.

Buy a Star Machine. I'm going to post a new thread about it now. But expect to spend 600-1500 for a clone, you will save many many dollars over the long run instead of replacing $200+ sensors that are OK. Also, if the cash is that tight, you can advertise locally on CL to diagnose MBZ cars at $50/pop. You'll get the cost back in no time.

Sometimes oxygen sensors can cause that code too. When is the last time you replaced your primary oxygen sensors?

Good idea. Just in case, I have Carsoft which is a good Star clone IMO

I have a few links for StarClone. It is important to get it with developer tools and also the ability to return if developer is not working. You will definitely have to do some programming with it right away to check. I am thinking I will change the setting on mine to RON93 since all that's all I really use anyway. Any suggestions on other changes that can be made to the C43 to test the developer tools? Not as easy as changing the suspension settings on the newer models lol.

Things to look at:

1. Wires, on another forum someone makes a distinction between good clone wires and bad clone wires. They mention something about military grade wires. not really sure what that means, guessing some are thinker and have better rubber/plastic connectors.

2. Multiplexer. C3/C4/Wireless. They are saying that MBZ trucks are 24v opposed to cars that have 12v. They claim many multiplexers will not survive the higher voltage. So good idea to plug it into the 24v vehicle if possible, thinking that a clone that survives the higher voltage is a better quality clone.

3. Harddrive. The only other thing I can remember is that the MBStar software is highly reliant on the HDD, so it is much better to get a SSD as they are much faster. Many people also claim that buying the HDD alone (without computer) is difficult to set up and relies on compatibility software, I would guess that one of these emulators will also slow down the system because I have used emulators on different applications and they are slow and glitchy. I think the emulator has to be used because MBZ Star will only run on particular computer models, one being an IBM and the other a DELL. I believe people seem to like the DELL better.



A few of the links I found:

Selecting the right Star

http://www.mbstarshop.com/

AliExpress (My understanding is that everything bought at AliExpress can be returned, please verify for yourself.

Ebay


I emailed some guy off ebay asking if developer tools were enabled and he emailed me back with his telephone number. I never called him but it is a good sign, I will wait maybe another week or two and try calling him them.




DRB, was interested if your carsoft pulls abs/bas/esp/srs codes?

Yes and erased. I'm leaving for 2 weeks vacation at the end of the month and will do a complete scan before leaving TP check if everything is OK. I'll keep you posted.