Mercedes

Have Mercedes Questions? Ask a Mechanic for Answers ASAP

Ask an Expert,
Get an Answer ASAP!

Mercedes

98 ML320: Check engine light..OBD2 codes p300, P0304..MAF..O2 sensor

Customer Question
98 ML320 w/ 130k....
98 ML320 w/ 130k. Check engine light with OBD2 codes P0300, P0304, P0305, P0306. suspect MAF or O2 sensor. Drives fine until accelerate too quickly, then pulls codes. Can reset codes and it's fine until same situation occurs again. Seems like truck is going into limp mode. Have cleaned MAF with no change, but hope there is a way to identify more specifically which sensor is responsible or which of the 4 oxygen sensors would be most likely. Had been great until 2 days ago and started all of a sudden. Would think o2 sensor or MAF would pull different codes in addition to random misfires.
Submitted: 6 years ago.Category: Mercedes
Show More
Show Less
Ask Your Own Mercedes Question
Answered in 1 minute by:
7/12/2011
Mercedes Mechanic: Marty, Mercedes Technician replied 6 years ago
Marty
Marty, Mercedes Technician
Category: Mercedes
Satisfied Customers: 54,174
Experience: Bosch Certified Master Tech. Over 35 years experience.
Verified

eurotec :

Hi, this sounds more like a restricted catalytic converter for cylinders 4, 5 and 6.

eurotec :

I'd perform a converter back pressure test or just loosen the converter and road test the car and see if that solves the problem.

eurotec :

If it were a maf or O2 sensor you would have fuel trim codes or oxygen sensor codes.

eurotec :

Your symptoms are typical of a plugged converter.

eurotec :

Let me know if you have any questions or if you need more help with it.

eurotec :

And please remember to click Accept so I receive credit for my help.

Ask Your Own Mercedes Question
Ask Marty Your Own Question
Marty
Marty
Marty, Mercedes Technician
Category: Mercedes
Satisfied Customers: 54,174
54,174 Satisfied Customers
Experience: Bosch Certified Master Tech. Over 35 years experience.

Marty is online now

A new question is answered every 9 seconds

How JustAnswer works:

  • Ask an ExpertExperts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional AnswerVia email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction GuaranteeRate the answer you receive.

JustAnswer in the News:

Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.

What Customers are Saying:

I would (and have) recommend your site to others I was quite satisfied with the quality of the information received, the professional with whom I interacted, and the quick response time. Thanks, and be sure that I'll be back whenever I need a question answered in a hurry.

Stephanie PElm City, NC

used your service this weekend with "Trecers" help. thank you ,thank you, thank you. replaced an A/C fan motor. Local Auto Zone had part. $15.00 "tracer" fee and $40.00 for parts, I saved several hundreds of dollers at a shop. i will recommend you and use you in the future.

David L.Richmond, TX

9 dollars, 2 hours of my time, and I drove away. Your diagnosis was right on the mark. Thank you so much.

PhilMarysville, CA

Lurch. Thank you very much. I had real doubts about this website but your promptness of response, quick followup and to the point answer with picture was incredible.

CharlesWalnut Creek, CA

As a single woman, I really appreciate an excellent and affordable opinion.
Thank you Geordie, I will not hesitate to contact justanswer in the future!

SueCharleston, WV

Another great insight to what may be the problem. I will have my mechanic take a look at it tomorrow. Thanks again, Frank...you do indeed know your stuff.

JimCastleberry, FL

Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help.

Mary C.Freshfield, Liverpool, UK

< Previous | Next >

Meet the Experts:

MB Paul

MB Paul

Mercedes Technician

3,567 satisfied customers

Qualified Mercedes Benz Diagnostic Technician - 20+ years experience - Workshop Foreman for Mercedes

Marty

Marty

Mercedes Technician

54,174 satisfied customers

Bosch Certified Master Tech. Over 35 years experience.

Lou P. master tech

Lou P. master tech

Mercedes Technician

3,502 satisfied customers

15 years master certified 100% fix rate and have access to factory radio codes, wiring, and instructions.

Michael Warfield

Michael Warfield

Factory Mercedes-Benz Technician

3,131 satisfied customers

Mercedes-Benz Master Certified technician

Matt

Matt

Engineer

591 satisfied customers

Mechanical Engineer with 23 years experience in the auto industry, 8 yrs in formula 1 engine testing

promerc

promerc

mercedes diagnostic technician

553 satisfied customers

Qualified mercedes diagnostic technician & service team manager , ATA registered Master tech

Hipo64

Hipo64

Mercedes Technician

443 satisfied customers

Work and diagnose electronics on daily basis.

< Previous | Next >

Related Mercedes Questions
Have a code P22a1 oxygen sensor bank1 sensor2. Vehicle runs
Have a code P22a1 oxygen sensor bank1 sensor2. Vehicle runs fine when cold but after it heats up has a hesitation with an squeal ( like its sucking air) around 1800-1900rpm. Any ideas? … read more
Eurocar Inc
Eurocar Inc
Master Audi/VW Tech
Associate Degree
1,773 satisfied customers
Misfiring cylinders 1 2 3. Random. 1999 ml320. Nothing yet.
only one side of the cylinder bank misfires, passengers side… read more
Marty
Marty
Mercedes Technician
54,174 satisfied customers
Lou i have recorded the Live data i had a scanner but i
Lou i have recorded the Live data i had a scanner but i didn't know that is can show the data. however here is video.. maybe its can help somehow .. because i have no clue how to red this data and whe… read more
Lou P. master tech
Lou P. master tech
Mercedes Technician
Bachelor's Degree
3,502 satisfied customers
We have a 2002 C230 coupe with a P0174 code on a dash check
we have a 2002 C230 coupe with a P0174 code on a dash check engine light. how can we fix it so we can get our emmission check off? … read more
BOBBYSS
BOBBYSS
TECHNICIAN/ADVISOR
Associate Degree
8,343 satisfied customers
Marty, Having an issue with my 2007 Mercedes E350, it is
Marty,Having an issue with my 2007 Mercedes E350, it is throwing codes for the heating side of the front two oxygen sensors. I just replaced both front oxygen sensors w/ bosch units and 10 minutes dow… read more
Lou P. master tech
Lou P. master tech
Mercedes Technician
Bachelor's Degree
3,502 satisfied customers
What could it be? 1993 300E 2.8 6CYL. I'm fixing it myself.
Yes I'm fixing it myself. So far new plugs and new ignition coil and oxygen sensor … read more
Matt
Matt
Engineer
Bachelor's Degree
591 satisfied customers
Just wonder if w210 has oxygen sensor fuse ?? Becouse i have
Just wonder if w210 has oxygen sensor fuse ?? Becouse i have faulty oxygen sesnors (Upstream) both.. I am curious what can cause them go bad.. iv just cleaned MAF with electrical connector.. but I sti… read more
Pete
Pete
Independent Auto Technician
Vocational, Technical or Trade Scho
138 satisfied customers
E430 runs great except when weather gets hot. After about
e430 runs great except when weather gets hot. After about one hour in hot weather the engine will stall out when gas pedal is depressed after stop. Check engine light comes on and then goes off. … read more
sprinkles08
sprinkles08
Technician
High School or GED
11 satisfied customers
I cannot find anyone to work on my 2009 Smart Car. The
I cannot find anyone to work on my 2009 Smart Car. The closest dealership is in Charleston, SC and I took it there but they do not have the parts to fix the blower for the air conditioner or the oxyge… read more
David Craig
David Craig
OWNER/MECHANIC
Associates
3,943 satisfied customers
Marty.. i have a question about my rattle.... its like
Hi Marty.. i have a question about my rattle.... its like shaking and rattling... Here in Binghamton NY where i live..i ask auto shop Precision to check my front suspension.. and the told me that susp… read more
Marty
Marty
Mercedes Technician
54,174 satisfied customers
I own mercede ML 320 model 2000, 3.2. My car performance is
I own mercede ML 320 model 2000 , 3.2 . My car performance is not good and random stall . Having , following error codeP0173 , P0170 ,P0130 +random cylinder mis fire I have replace 02 sensor bank 1 bu… read more
Matt
Matt
Engineer
Bachelor's Degree
591 satisfied customers
On E430 4matic its 722.6 Transmission.. how to check level?
On E430 4matic its 722.6 Transmission.. how to check level ? Some people saying that you should put in "Park" or "Neutral" and some saying put in "Drive".. Which is best Option?… read more
Marty
Marty
Mercedes Technician
54,174 satisfied customers
2000 E430 LEFT BANK SHUTS DOWN AFTER HARD ACCELERATION NEW
2000 E430 LEFT BANK SHUTS DOWN AFTER HARD ACCELERATION NEW CAT ON THAT BANK AND PLUGS SWAPPED COILS FROM BANK TO BANK NEW PLUG WIRES … read more
Marty
Marty
Mercedes Technician
54,174 satisfied customers
I had my car tuned up. Two days latter I fueled it with
I had my car tuned up. Two days latter I fueled it with Shell premium gas and my engine light came on. I have had it reset by a shop twice and put in a lower grade gas , but it is still on. I do not k… read more
Michael Warfield
Michael Warfield
Factory Mercedes-Benz Technician
Vocational, Technical or Trade Scho
3,131 satisfied customers
I have a 2008 c300 and it sometimes hesitate taking off, and
I have a 2008 c300 and it sometimes hesitate taking off, and the tachometer moves a little during driving. Took to Autozone to be checked, and the code came up as if there was a problem with the oxyge… read more
Pete
Pete
Independent Auto Technician
Vocational, Technical or Trade Scho
138 satisfied customers
Second opinion] I have 2005 CLS 350 which i dont use oftenly
I have 2005 CLS 350 which i dont use oftenly it is only passed 53000 mile, i noticed a black smoke from exhust with noticable drop in power. I took it to my mechanic which they are experts in Benz and changed first the sparkles then it runs good for 2 days and then the problem returned after that i have changed the air mas sensor the car run soomthly again for 2 days then the problem returned then i have changed the injectors but no difference … read more
Marty
Marty
Mercedes Technician
54,174 satisfied customers
I have a 2009 mercedes benz c63amg and I keep getting a code
I have a 2009 mercedes benz c63amg and I keep getting a code p0050 what do I have to replace or fix to get rid of this code… read more
Marty
Marty
Mercedes Technician
54,174 satisfied customers
I just bought a 2007 s550, and the check engine light turned
Hi, I just bought a 2007 s550, and the check engine light turned on reading for 3 codes … read more
Marty
Marty
Mercedes Technician
54,174 satisfied customers
Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Show MoreShow Less

Ask Your Question

x