Fitment notes: OEM size: 12V 12Ah AGM auxiliary/support battery (Mercedes-Benz AUX-type, e.g. A000 906 xx xx) · Location: engine compartment near the main battery/firewall area (some MFA2 platform cars locate it under a front seat or behind side trim — exact position not confirmed for this build) · Purpose: Voltage stabilization and electrical system backup during ECO start/stop restarts, maintaining power to electronics when main battery voltage dips
As an Amazon Associate and Autel/ANCEL partner, OLP earns from qualifying purchases — how we link. This never changes the specs we publish.
Every control module on the 2020-2026 Mercedes-Benz CLA45 AMG — 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)2.5 hr R&Rsecurity gateway +1.2 hr▸ programming details
⚠️ Memory seat and AMG performance seats. Basic adaptation possible with high-end aftermarket tools.
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 CLA45 AMG 2.0L I4 Turbo M139 and can vary by trim.
🔧 Database maintained under the daily editorial review of Chris Hackleman · Master Technician · 20+ years.