Check engine light on
 

I have a 200 ML 320 with about 120K miles. After a 1000 mile road trip my check engine light came on and stays illuminated. The car feels like it is miss firing. At times it will run so rough that I cannot accelarate. When this happens I shut the engine down and restart it and it runs much better it will still miss fire slightly but I can accelarate normally.

I have three questions:

1. Any ideas as to what the problem may be?
2. Can I hook up a standard OBD 2 to the on-board computer to get a read out of the check engine codes?
3. Where can I find a list of all trouble codes and their meanings

Thanks,

Dan

Went and bought an OBD 2 scanner and the following Trouble codes Popped up:

P0300 -----> Random Multiple Cylinder Misfire
P0301 -----> Cylinder 1 Misfire
P0302 -----> Cylinder 2 Misfire
P0303 -----> Cylinder 3 Misfire
P0306 -----> Clylinder 6 Misfire

Also someother codes Under the "Mill" on indicator popped up saying there were 9 possible emission problems:

Misfire
Fuel
Comp
Catylast
Evap
Sec Air
O2 sensor
O2 HTR
EGR

Does this make sense to anyone?

I have a similar problem on my '01 ML320, although at only 55K miles - check engine light came on, the engine stalls when accelerate, although only when cold, other than that it runs ok. Then last week I took the car to the dealership for the scheduled service A maintenance, and ask them to diagnose a problem, and they said it's the 'air mass sensor' (part # MB112-094-00-48). They estimated the total cost of parts and labor at about $800.

Ned

Thanks for the infor Ned. I'm hoping that is all it is. I took the Mass Air flow unit out yesterday and cleaned it with some electronic contact cleaner and reinstalled it. At that point I used my newly purchased OBD scanner from Auto Zone ($49.00) and cleared the codes. I fired up the motor and took it for a test run and so far the car seems to be running fine and no check engine light so far. I'm hoping that I solved the problem. In regards to your car Ned to change the Mas Air flow sensor with take you about ten minutes and probably save you a ton of money on Labor. It's very simple.

MAF should cost no more than $450 installed at the dealer. $150 if you do it yourself. Mechanical skill level 1 on a scale of 1 to 100. Do not buy from E-Bay - they are all junk. Buy MAF from reputable parts supplier like German Star or Autohaus AZ. No computer resetting needed, code will clear in a few cycles of driving. $800 is an absolute rip-off.
Cleaning the MAF is a temporary fix at best. Cleaning, if successful, will only last for a few weeks or days.
Mike

Mine is '02 ML 320 A/T and I experienced the same symptom/indications you have described here. OBD-II indicated that one of my spark plug wires was defective. So I replaced the affected wire and ran the OBD-II again to clear the fault and since then that same light never came on. I hope this answers your questions.

misfiring codes
 

I also have a 2002 ml320 with 127k miles. Engine lights on sometimes. stalls sometimes on idle. codes are p2043, p2046, p2050,p2056,p2055,p2054, these all are mifire codes for different cylinders. most of the time it runs fine. any ideas?

2002 ML320 150+K check engine light on
 

My check engine light came yesterday, the vehicle is running normally.
Any suggestions appreciated. Thanks.

The complete veh. must be scanned for codes. Cannot help you unless this is done.

code P0446 Evaporative system vent control circuit

code P0455 Evaporative Emission system leak Detected (gross leak/no flow

code P0446 Evaporative Emission system Vent control Circuit

Remove the gas cap and flip the gasket and re-tighten the cap until you hear the clicks.

If this does not correct the condition you will have to have a smoke test done on the Evaporative System to find the location of the leak.

Hi , should I expect the light to go off immediately after flipping the gasket? because it's still on but all I did was start it and checked the light. Thanks

Why didn't you try clearing the codes and see if any or all of the codes returned?

How do I clear codes on a 2002 Ml320?

With a scanner. I'm assuming you have one since you posted codes.

Thank you! check engine light is off :)

Standard OBD2 scanner use for check engine code that support below fuction:

Read & Clear DTCs
Read Live Data
Identify VIN information
Views freeze frame data
Turns off Malfunction indicator Light(MIL)
Display monitor test(mode 6)
Read pending fault code
DTC code look up

The point to check emission-relate test,I recommend nice DIY auto diagnsotic tool ,just $26!

On my 1999 ML430 with 200K miles I had P0446 code it was the purge valve not holding vacuum.
After replacing the purge valve and once the PCM was able to actually test the EVAP system..... code P0455 Large EVAP Leak came on..With a smoke machine I found the leak at the Fuel Filter vent hose.
What helped me a lot was watching videos on how EVAP works and what each component does.