Mercedes 722.9 ISM Intelligent Servo Module A0002701752

The ISM (intelligent servo module) is the electric unit bolted to the side of the Mercedes 722.9 7G-Tronic transmission that physically moves the selector shaft into Park, Reverse, Neutral and Drive on cars with the column or console direct-select shifter. This replacement references OE numbers A0002701752 and A0002701852. Listed fitment covers 722.9-equipped models including the W212 E-Class, W164 M-Class, X164 GL, X166 GLS, W251 R-Class, CLS and S-Class coupe. Match the number on your old module before ordering.

A failing ISM shows up as the car refusing to go into Park, a flashing or missing gear indicator on the dash, a transmission malfunction or "Visit workshop" warning, or the shifter selecting a gear the transmission never engages. Before replacing it, scan for ISM and CAN communication codes and check battery voltage, since a weak battery can set the same faults.

The module mounts outside the case, so the transmission stays in the car. Disconnect the battery, unplug the connector, unbolt the module from the selector shaft, and note the linkage position as it comes off. The new module has to be coded to the vehicle (SCN coding or initialization with a Mercedes-capable scan tool) and the Park position taught before it will shift correctly. Plan for that step before you start.