OBD 2 trouble
Thread Starter
Junior Member
Joined: Nov 2014
Posts: 36
Likes: 2
From: Los Angeles, CA
2025 GLE 580, 2015 ML400
OBD 2 trouble
I need to get my 2015 ML400 smog checked. The ECU appears to reset itself every time the engine is turned off, however. This causes it to fail the check unless I drive it for 25 - 30 miles first and then go straight to the smog check place without turning off the engine, which is ... impractical. Has anyone else experienced this issue? Any tips? I can take it to my mechanic and have him try to fix the resetting, but I have low confidence in that working.
Out Of Control!!
Joined: Apr 2019
Posts: 11,923
Likes: 6,776
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
FAILING SMOG CHECK
I need to get my 2015 ML400 smog checked.
The ECU appears to reset itself every time the engine is turned off, however.
This causes it to fail the check unless I drive it for 25 - 30 miles first and then go straight to the smog check place without turning off the engine, which is ... impractical.
Has anyone else experienced this issue?
Any tips? I can take it to my mechanic and have him try to fix the resetting, but I have low confidence in that working.
The ECU appears to reset itself every time the engine is turned off, however.
This causes it to fail the check unless I drive it for 25 - 30 miles first and then go straight to the smog check place without turning off the engine, which is ... impractical.
Has anyone else experienced this issue?
Any tips? I can take it to my mechanic and have him try to fix the resetting, but I have low confidence in that working.
I can't believe your ECU is "resetting itself" at key off. It must retains all monitors data... if not it is faulty.
However if ECU is manually reset using an OBD scanner, then ECU need multiple driving-cycles to refresh "monitors ready" status.
Your engine may have combustion issues requiring repairs before it can pass SMOG check (spark plugs, coils, lambda sensors...)
You can help cleanup the engine smog components by driving at Hwy speed for 20mn.
If your engine has been using stock oil, it.won't get fixed overnight.
