Oneslip

I have read through all the disconnected battery issues and I know how to resync the windows,sunroof, esp etc. My question is this, I do not drive my car very often and the state I live in requires an emissions inspection: the shop was unable to get a reading and asked if my battery had been dead and it has in the past as I don't drive the car enough. They said the computer had to recycle and then it would read and they said I had to drive the car to get it to do this. I drove it on the hwy for bout an hour and drove around town a bit and let the car sit for an hour then I took it back to the shop and they still could not get a reading, they said let it sit overnight and a cool cycle should correct it. I asked them if the computer could be shot and they said the computer was Ok it just needed to cycle and suggested I just drive the car. Apparently BMW and Volkswagons do the same thing??? Anyone heard of this and is there a driving technique that could get this to recycle quicker? I've had the cars for a number of years and have not had an issue like this before when getting it inspected.

Tangerine

From the sticky up top....

https://mbworld.org/forums/c-class-w...g-battery.html

Oneslip

Thanks for the link Tangerine. I did not read anything specific to what my car is doing, I was hoping there was a way to reset the computer for emission inspections. I understand these really are not the resets a driver would notice like windows etc.

jokerswld34

my car did the same thing for my last inspection. although i drive my car, i had my a/c unit serviced the day before the inspection and the computer wasn't reading either so i got a rejection sticker. i was told to drive 150 miles and come back and it would be all good. to be on the safe side i went for a nice long drive and returned the next day and the computer read everything just fine. i wouldnt worry about it but you do need to turn the car out every once in awhile.

Oneslip

Thanks Joker, I guess I'm going for a nice Sunday drive this weekend. I had driven it about 60 miles today and at high rates of speed as well to help warm up the catalytic converter. I knew somone out there had to of had this happen to them & had a solution. It just sucks because I really like my car and when this s*** happens I think about sellin.

jokerswld34

you're welcome mate. i wouldn't think about selling just yet my friend. my mercedes has been the most reliable car i've ever owned or been around. ill take these stupid little quirks any day compared to major problems commonly found in Audi, VW and BMW. The trick to the Benz is driving it hard now and again as if you were turning out a horse. the harder you push it, the less problems you'll encounter (i drive hard every day with lots of work done and have experienced zero engine problems aside from a/c compressor). you just have to expect some silly problems to arise and that your car is finicky. enjoy the drive and good luck. cheers!

Oneslip

Here is the procedure I found. However, be aware that conditions must be exactly right to reset. It may take several tries over many days.
The OBDII drive cycle begins with a cold start (coolant temperature below 122 degrees F and the coolant and air temperature sensors within 11 degrees of one another).

NOTE: The ignition key must not be on prior to the cold start otherwise the heated oxygen sensor diagnostic may not run.

1. As soon as the engine starts, idle the engine in drive for two and a half minutes with the A/C and rear defrost on. OBDII checks oxygen sensor heater circuits, air pump and EVAP purge.

2. Turn the A/C and rear defrost off, and accelerate to 55 mph at half throttle. OBDII checks for ignition misfire, fuel trim and canister purge.

3. Hold at a steady state speed of 55 mph for three minutes.

OBDII monitors EGR, air pump, O2 sensors and canister purge.

4. Decelerate (coast down) to 20 mph without braking or depressing the clutch. OBDII checks EGR and purge functions.

5. Accelerate back to 55 to 60 mph at æ throttle. OBDII checks misfire, fuel trim and purge again.

6. Hold at a steady speed of 55 to 60 mph for five minutes.

OBDII monitors catalytic converter efficiency, misfire, EGR, fuel trim, oxygen sensors and purge functions.

7. Decelerate (coast down) to a stop without braking. OBDII makes a final check of EGR and canister purge.
Here is the procedure I found. However, be aware that conditions must be exactly right to reset. It may take several tries over many days.

I also read something to that the RPMs cannot exceed 3K and the MPH needs to be below 60 for the duration of the test. I'm gonna give this a try and hopefully will be the OBD to be read and get my passing inspection.