Every control module on the 2024-2026 Mercedes-Benz G-Class — 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.
Battery Management System (BMS) 2.5 hr R&R security gateway +1.5 hr ▸ programming details
📍 Under rear cargo floor or rear seat area
🔧 Xentry Diagnostics + SCN online
⚠️ 48V mild hybrid system on some 2024+ models. VIN-locked, requires SCN coding and battery registration.
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
⚠️ VIN-locked, requires transmission fluid change after replacement. SCN coding mandatory.
Climate Control Unit (CCU) 2.0 hr R&R dealer / factory tool +0.5 hr ▸ programming details
📍 Behind center dashboard, above transmission tunnel
🔧 Xentry Diagnostics
⚠️ Requires coding for vehicle configuration. Aftermarket tools may work for basic coding.
4MATIC Control Unit (4M) 2.0 hr R&R dealer / factory tool +0.8 hr ▸ programming details
📍 Transfer case, mounted on housing
🔧 Xentry Diagnostics
⚠️ Controls 4WD system and differential locks. Requires adaptation for tire size and gear ratios.
Roof SAM (SAM-Roof) 2.0 hr R&R dealer / factory tool +0.8 hr ▸ programming details
📍 Headliner, center above rear seats
🔧 Xentry Diagnostics
⚠️ Controls interior lighting, sunroof, and roof-mounted accessories. Present on models with panoramic roof.
Signal Acquisition and Actuation Module - Rear (SAM-R) 1.8 hr R&R security gateway +1.5 hr ▸ programming details
📍 Behind right rear side panel in cargo area
🔧 Xentry Diagnostics + SCN online
⚠️ VIN-locked, requires SCN coding. Controls rear lighting, fuel pump, trailer functions.
Electronic Ignition Switch (EIS) 1.8 hr R&R security gateway +1.5 hr ▸ programming details
📍 Steering column, integrated with ignition switch
🔧 Xentry Diagnostics + SCN online
⚠️ VIN-locked, part of security triangle. Key programming requires online authorization. All keys must be present.
Camera Control Unit / Surround View (CCU) 1.5 hr R&R dealer / factory tool +0.8 hr ▸ programming details
📍 Behind dashboard, center or in headliner
🔧 Xentry Diagnostics
⚠️ Enhanced 360-degree system. Requires camera calibration and alignment after replacement.
Electric Power Steering Control Unit (EPS) 1.5 hr R&R security gateway +0.8 hr ▸ programming details
📍 Steering column, below dashboard
🔧 Xentry Diagnostics + SCN online
⚠️ VIN-locked, requires steering angle sensor calibration after coding.
Head Unit / MBUX (HU/MBUX) 1.5 hr R&R dealer / factory tool +0.8 hr ▸ programming details
📍 Center dashboard, integrated with display
🔧 Xentry Diagnostics
⚠️ MBUX system. Requires coding for vehicle options and user profile transfer. OTA update capable.
Airmatic / Active Body Control Module (ABC/ADS) 1.5 hr R&R dealer / factory tool +0.8 hr ▸ programming details
📍 Under vehicle, near front axle or in engine bay
🔧 Xentry Diagnostics
⚠️ Requires ride height calibration and suspension adaptation after replacement.
Motor Electronics / Engine Control Unit (ME/ECU) 1.2 hr R&R security gateway +1.0 hr ▸ programming details
📍 Engine bay, left side firewall near brake booster
🔧 Xentry Diagnostics + SCN online
⚠️ VIN-locked, requires SCN coding and EIS pairing. Must be programmed online via Mercedes servers.
Tailgate Control Module (TGM) 1.2 hr R&R aftermarket tool +0.3 hr ▸ programming details
📍 Inside tailgate, left side
🔧 Xentry or Autel MaxiSys
⚠️ Controls power tailgate and spare tire carrier. Requires position learning after replacement.
Telematics Communication Module (TCM) 1.2 hr R&R dealer / factory tool +0.5 hr ▸ programming details
📍 Behind dashboard, center or under rear seat
🔧 Xentry Diagnostics
⚠️ 5G capable on 2024+. Requires Mercedes me account activation and cellular carrier provisioning.
Electronic Stability Program Control Unit (ESP/ABS) 1.0 hr R&R security gateway +1.0 hr ▸ programming details
📍 Engine bay, left side near battery
🔧 Xentry Diagnostics + SCN online
⚠️ VIN-locked, requires brake bleed and SCN coding. Integrated with ABS hydraulic unit.
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, mileage programming requires online authorization. Part of security triangle with EIS/ECM.
Door Control Module (DCM) 1.0 hr R&R aftermarket tool +0.3 hr ▸ programming details
📍 Inside each door (4 modules total)
🔧 Xentry or Autel MaxiSys
⚠️ Controls windows, mirrors, locks per door. Requires window initialization after replacement.
Central Gateway Module (CGW) 1.0 hr R&R security gateway +1.5 hr ▸ programming details
📍 Under dashboard, center near OBD-II port
🔧 Xentry Diagnostics + SCN online
⚠️ Enhanced security gateway. VIN-locked, controls all module access. Replacement is complex and expensive.
Radar Sensor / DISTRONIC Control Unit (RSU) 1.0 hr R&R dealer / factory tool +1.0 hr ▸ programming details
📍 Front bumper, center behind grille
🔧 Xentry Diagnostics
⚠️ Enhanced radar for Level 2+ autonomy. Requires radar alignment and calibration after replacement.
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, requires SCN coding and crash data verification. Must clear crash data if present.
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
⚠️ Digital Light technology on 2024+. Requires headlight aim calibration after replacement.
Parktronic Control Unit (PTS) 0.8 hr R&R aftermarket tool +0.3 hr ▸ programming details
📍 Behind rear bumper, center
🔧 Xentry or Autel MaxiSys
⚠️ Requires sensor calibration after replacement. Integrated with camera system on some models.
Trailer Module (TM) 0.8 hr R&R aftermarket tool +0.3 hr ▸ programming details
📍 Rear frame, near hitch receiver
🔧 Xentry or Autel MaxiSys
⚠️ Controls trailer lighting and brake controller. Requires coding for trailer presence and type.
Seat Control Module (SCM) 0.6 hr R&R aftermarket tool +0.3 hr ▸ programming details
📍 Under each front seat (left and right)
🔧 Xentry or Autel MaxiSys
⚠️ Requires adaptation for seat memory and massage functions. Most aftermarket tools can code.
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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