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2004-2014 Mercedes-Benz C-Class: 7G-Tronic (722.9) conductor plate

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specific things to inspect and negotiate

What goes wrong

The 7-speed automatic used across nearly the whole lineup this era has a documented conductor-plate (internal sensor/computer) failure, harsh shifts, limp mode, no-start-in-gear. Repairable without replacing the whole transmission, but real money.

Federal record for the 2009 Mercedes-Benz C-Class, pulled from NHTSA when this page was built:
670 owner complaints on file , most-reported: AIR BAGS (195) · STEERING (158) · ELECTRICAL SYSTEM (147).
0 safety recalls listed.
Complaint volume tracks how many were sold as well as how they held up , read it as a pattern, not a score. Counts change; confirm live at nhtsa.gov or by running the free check below.
Rough cost: $1,200-$2,500 conductor plate/valve body. Broad estimates , labor rates and parts vary widely by region and shop.

What to do about it

Before you hand over cash: Test drive through all gears, cold. Harsh 2-3 or 4-5 shifts, or any limp-mode history = get the transmission scanned before money moves. Fluid service records matter, “sealed for life” isn’t.

Whatever you find, a $100-150 pre-purchase inspection by an independent mechanic is the cheapest money you’ll spend on any used car , including this one.

Run the full free check on this C-Class →

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General reference information only , not a mechanical inspection, appraisal, or vehicle history report, and not specific to any individual car. Failure patterns describe documented tendencies across many vehicles; any single car may be better or worse. Cost figures are rough estimates , verify locally. The absence of a warning is not a statement that a car is safe or problem-free. Always verify recalls directly with NHTSA and get a pre-purchase inspection. Not affiliated with any manufacturer, dealer, or reporting service. No affiliate links, no commissions, no ads. © Used Car Informer, operated by MCC LLC · v6.6