Fitment notes: AGM battery required for start-stop system; located in trunk; vented to exterior
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Every control module on the 2022-2025 Mercedes-Benz CLS — where it lives, replacement time, and what it takes to program a replacement. Modules marked dealer / factory tool won't work after a part swap alone — budget for programming.
Transmission Control Unit (TCU)3.5 hr R&Rsecurity gateway +1.0 hr▸ programming details
📍 Transmission bell housing or valve body (internal on 9G-TRONIC)
🔧 Xentry Diagnostics + SCN online
⚠️ 9G-TRONIC transmission; TCU integrated into valve body, requires transmission oil service after replacement.
Hybrid Control Unit / Battery Management System (HCU/BMS)2.5 hr R&Rsecurity gateway +1.5 hr▸ programming details
📍 Trunk, left or right side panel, or under rear shelf
🔧 Xentry Diagnostics
⚠️ Handles Mercedes me connect services; requires SIM activation and account linking. 4G/LTE capable.
Fuel Pump Control Module (FPCM)0.6 hr R&Rrelearn only +0.2 hr▸ programming details
📍 Trunk, right side panel or near fuel tank
🔧 Xentry Diagnostics or Autel
⚠️ Simple adaptation after replacement; no VIN-lock.
Aftermarket tool coverage varies by software version and vehicle build — treat "aftermarket tool" rows as "usually possible" and verify against your tool maker's coverage list before promising a customer. Spot a wrong location or hour? Tell us — corrections ship fast here.
Size-standard part numbers — verify your connector type before buying. Rear blades are model-specific; check the package's vehicle list.
Fuel economy figures are EPA data via fueleconomy.gov (median across matching trims). Performance figures are compiled estimates for the 2025 Mercedes-Benz CLS 3.0L Turbo I6 and can vary by trim.
🔧 Database maintained under the daily editorial review of Chris Hackleman · Master Technician · 20+ years and Jeff Moore · Master Mechanic · 20+ years.