Every control module on the 2019-2026 Cadillac XT4 — 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.
Heating, Ventilation and Air Conditioning Control Module (HVAC) 2.5 hr R&R dealer / factory tool +0.5 hr ▸ programming details
📍 Behind center stack, integrated with HVAC unit under instrument panel
🔧 GDS2/Techline Connect
⚠️ Dual-zone or tri-zone depending on trim; refrigerant recovery required; actuator calibration after programming
Transmission Control Module (TCM) 2.5 hr R&R security gateway +1.0 hr ▸ programming details
📍 Integrated into transmission valve body, accessed from underneath vehicle
🔧 GDS2/Techline Connect + SGW unlock
⚠️ 9-speed automatic; requires transmission fluid drain, valve body removal; adaptive relearn drive cycle required after programming
Electric Power Steering Control Module (EPSCM) 2.0 hr R&R security gateway +0.8 hr ▸ programming details
📍 Integrated into steering column assembly, below instrument panel
🔧 GDS2/Techline Connect + SGW unlock
⚠️ Steering angle sensor calibration required after replacement; torque sensor relearn procedure mandatory
Electronic Brake Control Module (EBCM) 1.8 hr R&R security gateway +0.8 hr ▸ programming details
📍 Engine compartment, driver side inner fender area, integrated with ABS hydraulic unit
🔧 GDS2/Techline Connect + SGW unlock
⚠️ Brake system bleed required after replacement; integrated with ESC and hill start assist
Transfer Case Control Module (TCCM) 1.5 hr R&R dealer / factory tool +0.5 hr ▸ programming details
📍 Mounted to transfer case assembly, under vehicle center (AWD models only)
🔧 GDS2/Techline Connect
⚠️ AWD models only; active torque distribution; clutch pack relearn required after replacement
Driver Assistance Control Module (DACM) 1.5 hr R&R security gateway +1.0 hr ▸ programming details
📍 Behind rearview mirror, integrated with camera housing, or behind instrument panel
🔧 GDS2/Techline Connect + SGW unlock + camera calibration
⚠️ Lane keep assist, lane departure warning, automatic emergency braking; camera calibration mandatory; 2020+ integrated with SVCM
Body Control Module (BCM) 1.5 hr R&R security gateway +1.2 hr ▸ programming details
📍 Behind center stack, above transmission tunnel, accessed by removing center console
🔧 GDS2/Techline Connect + SGW unlock
⚠️ Controls most body functions; all accessory modules must be reconfigured after replacement; option content programming critical
Surround Vision Camera Module (SVCM) 1.5 hr R&R dealer / factory tool +0.8 hr ▸ programming details
📍 Behind rearview mirror, integrated with forward camera housing
🔧 GDS2/Techline Connect
⚠️ Premium Luxury and Sport trims; four-camera system; dynamic calibration required; windshield camera for lane keep assist
Gateway Module (GM) 1.3 hr R&R security gateway +1.5 hr ▸ programming details
📍 Behind center stack, near BCM, above transmission tunnel
🔧 GDS2/Techline Connect + SGW unlock
⚠️ Security gateway; controls access to all modules; replacement requires full vehicle reconfiguration; critical for network communication
Door Control Module (DCM) 1.2 hr R&R dealer / factory tool +0.3 hr ▸ programming details
📍 Inside each door, behind door panel (one per door with power features)
🔧 GDS2/Techline Connect
⚠️ Controls windows, locks, mirrors; driver door module is master; window auto-up/down relearn required
Engine Control Module (ECM) 1.2 hr R&R security gateway +1.0 hr ▸ programming details
📍 Engine compartment, driver side firewall area, mounted to bulkhead
🔧 GDS2/Techline Connect + SGW unlock
⚠️ VIN programming and security gateway unlock required; 2.0L turbo ECM location differs slightly from 2.7L turbo
Parking Assist Control Module (PACM) 1.2 hr R&R dealer / factory tool +0.5 hr ▸ programming details
📍 Behind rear bumper cover, center, or integrated with rear camera module
🔧 GDS2/Techline Connect
⚠️ Ultrasonic sensors front and rear; sensor calibration required; integrated with surround vision on Premium Luxury
Infotainment Control Module (ICM) 1.2 hr R&R dealer / factory tool +0.8 hr ▸ programming details
📍 Behind center touchscreen display, center stack
🔧 GDS2/Techline Connect
⚠️ 8-inch or 10-inch touchscreen depending on trim; CUE system; navigation data separate; OnStar reactivation required
Sensing and Diagnostic Module (SDM) 1.0 hr R&R security gateway +0.5 hr ▸ programming details
📍 Center console, below center stack, mounted to floor tunnel
🔧 GDS2/Techline Connect + SGW unlock
⚠️ Wait 2 minutes after battery disconnect before handling; crash data retrieval available; VIN and option programming required
Fuel Pump Control Module (FPCM) 1.0 hr R&R dealer / factory tool +0.3 hr ▸ programming details
📍 Under vehicle, mounted to fuel tank or frame rail near tank
🔧 GDS2/Techline Connect
⚠️ Controls fuel pump speed based on demand; configuration required for proper fuel delivery mapping
Liftgate Control Module (LGM) 1.0 hr R&R dealer / factory tool +0.4 hr ▸ programming details
📍 Inside liftgate, behind interior trim panel, driver side
🔧 GDS2/Techline Connect
⚠️ Power liftgate standard on most trims; hands-free operation requires calibration; pinch protection relearn mandatory
Magnetic Ride Control Module (MRCM) 1.0 hr R&R dealer / factory tool +0.5 hr ▸ programming details
📍 Rear cargo area, driver side, behind trim panel (Sport models with adaptive suspension)
🔧 GDS2/Techline Connect
⚠️ Optional on Sport trim; real-time damping control; damper calibration required; ride height sensor inputs
OnStar Communication Module (VCIM) 1.0 hr R&R security gateway +1.0 hr ▸ programming details
📍 Behind headliner, above rearview mirror area, or behind rear cargo trim panel (varies by year)
🔧 GDS2/Techline Connect + SGW unlock + OnStar activation
⚠️ OnStar subscription reactivation required; 4G LTE module; ESN registration with OnStar mandatory
Rear Radar Sensor Module (RRSM) 0.8 hr R&R dealer / factory tool +0.5 hr ▸ programming details
📍 Behind rear bumper cover, driver and passenger sides (two modules)
🔧 GDS2/Techline Connect
⚠️ Rear cross traffic alert and blind zone alert; two separate modules; calibration required after replacement
Instrument Panel Cluster (IPC) 0.8 hr R&R security gateway +0.5 hr ▸ programming details
📍 Instrument panel, behind gauge cluster lens, driver side
🔧 GDS2/Techline Connect + SGW unlock
⚠️ 8-inch digital display; mileage transfer from old module required; VIN and option programming mandatory
Headlamp Control Module (HCM) 0.8 hr R&R dealer / factory tool +0.3 hr ▸ programming details
📍 Behind left headlamp assembly, driver side front fender area
🔧 GDS2/Techline Connect
⚠️ LED headlamps; auto high beam and adaptive lighting on Premium Luxury/Sport trims require calibration
Remote Control Door Lock Receiver (RCDLR) 0.8 hr R&R security gateway +0.5 hr ▸ programming details
📍 Behind rear cargo trim panel, driver side, or integrated into liftgate module
🔧 GDS2/Techline Connect + SGW unlock
⚠️ All key fobs must be reprogrammed after replacement; passive entry antenna integration
Seat Control Module (SCM) 0.6 hr R&R aftermarket tool +0.2 hr ▸ programming details
📍 Under driver and/or passenger seat, mounted to seat frame (one per power seat)
🔧 GDS2 or Autel MaxiSys
⚠️ Memory seats require position relearn; heated/ventilated seat configuration; massage function on Premium Luxury trim
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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