Every control module on the 2021-2026 Mercedes-Benz Maybach GLS — 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&R security gateway +1.0 hr ▸ programming details
📍 Transmission bell housing, driver side
🔧 Xentry Diagnostics + SCN online
⚠️ 9G-TRONIC transmission. Requires transmission fluid change after replacement. VIN-locked SCN coding required.
Climate Control Unit (CCU) 2.5 hr R&R dealer / factory tool +0.5 hr ▸ programming details
📍 Behind center dashboard, above transmission tunnel
🔧 Xentry Diagnostics
⚠️ Requires HVAC system recalibration and zone configuration after replacement.
Electric Power Steering Control Unit (EPS) 2.0 hr R&R security gateway +1.0 hr ▸ programming details
📍 Steering column, integrated with steering gear
🔧 Xentry Diagnostics + SCN online
⚠️ Steering angle sensor calibration required after replacement. VIN-locked.
4MATIC Control Unit (4M) 2.0 hr R&R security gateway +1.0 hr ▸ programming details
📍 Under vehicle, mounted on transfer case
🔧 Xentry Diagnostics + SCN online
⚠️ All-wheel drive system. VIN-locked. Requires drivetrain relearn after replacement.
Signal Acquisition and Actuation Module - Rear (SAM-R) 1.8 hr R&R security gateway +1.5 hr ▸ programming details
📍 Right rear cargo area, behind trim panel
🔧 Xentry Diagnostics + SCN online
⚠️ Controls rear electrical functions. VIN-locked SCN coding required.
Central Gateway Module (CGW) 1.5 hr R&R security gateway +2.0 hr ▸ programming details
📍 Under dashboard, center above transmission tunnel
🔧 Xentry Diagnostics + SCN online
⚠️ Security gateway. Replacement requires all modules to be re-paired. Critical security component.
Active Multicontour Seat Module (AMSM) 1.5 hr R&R dealer / factory tool +0.5 hr ▸ programming details
📍 Under front seats, integrated with seat frame
🔧 Xentry Diagnostics
⚠️ Energizing comfort massage seats. Calibration and pressure sensor learning required.
MBUX Head Unit (MBUX/HU) 1.5 hr R&R dealer / factory tool +1.0 hr ▸ programming details
📍 Center dashboard, integrated with display screen
🔧 Xentry Diagnostics + SCN online
⚠️ Requires online activation and user profile transfer. Navigation and media settings must be reconfigured.
Airmatic / Active Body Control Module (ABC/ADS) 1.5 hr R&R security gateway +1.0 hr ▸ programming details
📍 Front left engine compartment, near shock tower
🔧 Xentry Diagnostics + SCN online
⚠️ E-Active Body Control system. Ride height calibration and sensor learning required. VIN-locked.
Motor Electronics / Engine Control Unit (ME/ECU) 1.2 hr R&R security gateway +1.0 hr ▸ programming details
📍 Engine compartment, left side firewall behind air filter housing
🔧 Xentry Diagnostics + SCN online
⚠️ VIN-locked, requires online SCN authorization from Mercedes servers. EIS security triangle pairing mandatory.
Electronic Ignition Switch (EIS) 1.2 hr R&R security gateway +1.5 hr ▸ programming details
📍 Steering column, integrated with ignition lock
🔧 Xentry Diagnostics + SCN online
⚠️ Part of security triangle with ECM and cluster. All keys must be reprogrammed. VIN-locked.
Rear Seat Control Module (RSCM) 1.2 hr R&R dealer / factory tool +0.5 hr ▸ programming details
📍 Under rear executive seats (2 modules for Maybach)
🔧 Xentry Diagnostics
⚠️ Maybach executive seating package. Controls recline, massage, heating, ventilation.
Electronic Stability Program Control Unit (ESP/ABS) 1.0 hr R&R security gateway +1.0 hr ▸ programming details
📍 Engine compartment, left front near brake master cylinder
🔧 Xentry Diagnostics + SCN online
⚠️ Integrated hydraulic unit. Brake bleeding required after replacement. VIN-locked.
Camera Control Unit / Surround View (CCU) 1.0 hr R&R dealer / factory tool +0.8 hr ▸ programming details
📍 Behind rearview mirror, integrated with camera
🔧 Xentry Diagnostics
⚠️ 360-degree camera system. Camera calibration and alignment required after replacement.
Instrument Cluster (IC) 1.0 hr R&R security gateway +1.0 hr ▸ programming details
📍 Dashboard, behind steering wheel
🔧 Xentry Diagnostics + SCN online
⚠️ VIN-locked, part of EIS security triangle. Mileage programming requires dealer authorization.
Door Control Module (DCM) 1.0 hr R&R dealer / factory tool +0.3 hr ▸ programming details
📍 Inside each door (4 modules total)
🔧 Xentry Diagnostics
⚠️ Window and mirror calibration required after replacement. One module per door.
Fuel Pump Control Module (FPCM) 1.0 hr R&R aftermarket tool +0.3 hr ▸ programming details
📍 Under vehicle, mounted on fuel tank
🔧 Xentry or Autel MaxiSys
⚠️ Basic adaptation only. Fuel tank may need to be lowered for access.
Restraint Systems Control Unit (SRS) 0.8 hr R&R security gateway +0.8 hr ▸ programming details
📍 Center console, under front seats mounting area
🔧 Xentry Diagnostics + SCN online
⚠️ VIN-locked. All airbag sensors and seat occupancy must be recalibrated after coding.
Intelligent Light System Control Unit (ILS) 0.8 hr R&R dealer / factory tool +0.5 hr ▸ programming details
📍 Each headlight assembly (left and right modules)
🔧 Xentry Diagnostics
⚠️ Headlight aim calibration required after replacement. Separate module per headlight.
Tailgate Control Module (TGM) 0.8 hr R&R dealer / factory tool +0.3 hr ▸ programming details
📍 Tailgate, left side behind trim panel
🔧 Xentry Diagnostics
⚠️ Power tailgate calibration and kick-sensor relearn required after replacement.
Parktronic Control Unit (PTS) 0.8 hr R&R dealer / factory tool +0.5 hr ▸ programming details
📍 Rear cargo area, right side behind trim
🔧 Xentry Diagnostics
⚠️ Parking sensor calibration required after replacement.
Rear Radar Sensor (RRS) 0.8 hr R&R dealer / factory tool +0.5 hr ▸ programming details
📍 Rear bumper, left and right corners (2 modules)
🔧 Xentry Diagnostics
⚠️ Blind spot assist and rear cross-traffic. Separate modules left and right.
Telematics Communication Module (TCM) 0.8 hr R&R dealer / factory tool +0.8 hr ▸ programming details
📍 Rear cargo area, left side behind trim panel
🔧 Xentry Diagnostics + online activation
⚠️ Requires Mercedes me connect subscription reactivation and online pairing.
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?
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