25909049 | Genuine GM® Anti-Lock Brake Module For 2008-2010 Express 1500, 2500

An Anti-Lock Brake Module (ABS Module) 25909049 is the electronic control unit that manages a vehicle's Anti-Lock Braking System (ABS). It works together with the hydraulic control unit (HCU) to prevent the wheels from locking during hard braking, helping the driver maintain steering control. Anti-Lock Brake Module For 2008-10 Express, Savana 1500, 2500, 3500 -  Refurbished & Tested – 100% Working Condition

General Specifications

Fitment

Fitment can vary by engine build and options. Match the part number on the part you are replacing, or contact us with your vehicle details before ordering.

Purpose & Function (Anti-Lock Brake Module)

Main purposes

1. Prevents wheel lock-up
   • Monitors the speed of each wheel.
   • Reduces brake pressure to a wheel that is about to lock.
   • Allows the wheel to keep rotating instead of skidding.
2. Maintains steering control
   • Because the wheels continue rotating, the driver can still steer around obstacles while braking.
3. Reduces skidding
   • Helps maintain traction on wet, snowy, icy, or loose road surfaces.
   • Improves vehicle stability during sudden stops.
4. Works with other safety systems
   The ABS module shares data with systems such as:
   • Traction Control System (TCS) – limits wheel spin during acceleration.
   • Electronic Stability Control (ESC/StabiliTrak) – helps prevent loss of control in turns or emergency maneuvers.
   • Electronic Brakeforce Distribution (EBD) – optimizes brake force between the front and rear wheels.
   • Hill Start Assist (on some vehicles).
5. Performs system diagnostics
   • Continuously checks the ABS system for faults.
   • Stores diagnostic trouble codes (DTCs) if a problem is detected.
   • Illuminates the ABS warning light when service is needed.

Signs of a Bad Anti-Lock Brake Module

Common signs of a bad ABS module

1. ABS warning light stays on
   • The most common symptom.
   • Indicates the ABS has detected a fault and may be disabled.
2. Traction Control or Stability Control warning lights
   • The Traction Control (TCS) or Electronic Stability Control (ESC/StabiliTrak) lights may also illuminate because these systems rely on the ABS module.
3. ABS does not activate
   • During hard braking, the wheels may lock up instead of pulsating as they normally would with ABS.
4. Brake pedal behaves abnormally
   • A hard, soft, or inconsistent brake pedal.
   • Unexpected pedal pulsation when ABS is not supposed to activate.
5. Speedometer or cruise control issues
   • On some vehicles, a failed ABS module can affect the speedometer or disable cruise control because wheel speed data is shared with other systems.
6. Diagnostic Trouble Codes (DTCs)
   • A scan tool may reveal codes such as:
     • C0265 – ABS relay circuit
     • C0241 – ABS/TCS control module fault
     • C0550 – Electronic Control Unit (ECU) malfunction
     • Other manufacturer-specific ABS communication or internal fault codes
7. ABS pump runs continuously (rare)
   • A stuck relay or internal module failure may cause the ABS pump motor to keep running, even with the ignition off, which can drain the battery.
8. Intermittent ABS operation
   • The warning lights may come and go.
   • ABS may work sometimes but not others, often due to internal solder cracks or electrical faults.

About GM

General Motors (GM) is one of the largest and most iconic automotive manufacturers in the world. Founded in 1908 and headquartered in Detroit, Michigan, GM designs, builds, and sells vehicles under several well-known brands, including Chevrolet, GMC, Cadillac, and Buick.
GM is known for its long history of innovation in the automotive industry, from developing early electric vehicles to advancing autonomous driving and connected car technologies. The company has a strong global presence and is committed to a future of zero crashes, zero emissions, and zero congestion, with significant investments in electric vehicles (EVs) and sustainable mobility.