Emissions - I/m Dynamometer Emissions Testing
Date: February 1, 2013Order No: S-B-14.00/31
Supersedes: S-SI-MBNA-14/12A, May 1998
Group: 14
Revision a:
Updated to include model application guide for I/M 240 dynamometer testing
SUBJECT:
MY-All, Models All
I/M 240 Emissions Testing on Dynamometer
The enhanced Inspection/Maintenance emission testing program (I/M 240) is in effect in several states.
It is recommended that all vehicles be tested on a 4-wheel dynamometer.
The following vehicle may be tested on a 2-wheel dynamometer:
^ Mercedes-Benz vehicles that are 2WD and not equipped with Acceleration Slip Regulation (ASR)
^ Mercedes-Benz Maybach and smart vehicles that are 2WD and have "Dyno-Mode" capability (must be activated)
The following vehicles must be tested on a 4-wheel dynamometer:
^ Mercedes-Benz vehicles equipped with ASR
^ Mercedes-Benz vehicles equipped with 4MATIC
^ Mercedes-Benz vehicles that are 2WD and do not have "Dyno-Mode" capability
Please see Attachment 1 for a list of vehicles that must be tested on a 4-wheel dynamometer.
Please see Attachment 2 for a list of vehicles with "Dyno-Mode" capability and the activation procedure.
According to US Environmental Protection Agency (EPA) procedures, if an emissions inspector has difficulty performing the I/M 240 test on a 2-wheel dynamometer, the following should be considered:
^ Test the vehicle on a 4-wheel dynamometer, or
^ Perform an optional emission test at idle +2500 rpm
An emissions inspector should also consider the options above if they are uncertain about the Dyno-M ode activation procedure or is uncertain about which vehicles can operate on a 2-wheel dynamometer.
Attachment 1: Vehicles That Must be Tested on a 4-Wheel Dynamometer
Please refer to the Vehicles Operator's Manual for details regarding ASR and 4MATIC.
Attachment 2: Dyno-Mode Activation Procedure for Operation of a 2WD Vehicle on a 2- Wheel Dynamometer