Code U0133 on the 2023 Ram 2500 indicates lost communication with suspension control module 'B'. The Ram 2500 may be equipped with various suspension control systems including air suspension, automatic load leveling, or Active Tuned Mass modules depending on configuration.
Ram 2500 Suspension Options
Heavy-duty Ram trucks offer optional rear air suspension for automatic load leveling when towing or hauling. The Active Tuned Mass system uses electronically controlled dampers to reduce vibration. These systems require control modules that communicate with the vehicle's network to function properly.
Towing and Hauling Effects
With U0133 present, automatic load leveling won't adjust for trailer or cargo weight. The truck may sag under load and headlight aim may be affected. Active ride management features won't function. Warning messages appear on the Driver Information Center. Trailer sway mitigation may also be limited.
Diagnostic Focus
Identify which suspension module corresponds to 'B' in your Ram's configuration. Air suspension modules are typically near the rear axle or compressor. Check for damage from towing equipment installation or road debris. Verify power, ground, and CAN communication at the module.
Repair Path
The heavy-duty truck environment exposes these modules to significant debris and weather. Inspect connectors carefully for damage. If the module requires replacement, Stellantis diagnostic equipment is needed for programming and system calibration.