ABS and Traction Control Lights On in 2025 R1T

ClearTheCode admin answer:

When both the ABS (Anti-lock Braking System) and Traction Control System (TCS) warning lights illuminate simultaneously on your 2025 Rivian R1T, it indicates a fault within a shared component or system. While your friction brakes may still function, critical safety features are likely disabled.

Common Causes:

• Wheel Speed Sensors: These are the most common culprits. Each wheel has a sensor that monitors its rotational speed. If a sensor is faulty, dirty, damaged, or its wiring is compromised, the ABS/TCS module loses crucial data, triggering both lights.
• ABS Module Failure: The ABS control module (also known as the Hydraulic Control Unit or HCU) is the brain of the system. A failure within this module can disable both ABS and TCS.
• Wiring Issues: Damaged or corroded wiring to the wheel speed sensors or the ABS module can interrupt communication, leading to warning lights.
• Brake Fluid Level: While less common for simultaneous ABS/TCS lights, a critically low brake fluid level can sometimes trigger general brake warnings that might indirectly affect these systems.
• Relay/Fuse Issues: A blown fuse or faulty relay powering the ABS system can cause it to malfunction.

Potential OBD Codes:

• C0031: Left Front Wheel Speed Sensor Circuit (or similar for other wheels)
• C0020: ABS Pump Motor Control Circuit
• C0040: Brake Pedal Position Sensor Circuit Malfunction
• U0415: Invalid Data Received from Anti-Lock Brake System Control Module

What You Can Do:

1. Check Brake Fluid Level: Visually inspect the brake fluid reservoir to ensure the fluid is between the MIN and MAX lines.
2. Visual Inspection of Wheel Speed Sensors: If accessible, you can visually inspect the wiring leading to the wheel speed sensors at each wheel for any obvious damage or disconnections. They are typically located near the wheel hub.
3. Scan for Codes: The most effective first step is to have an OBD-II scanner capable of reading ABS codes (not all basic scanners can) connected to your vehicle. This will provide specific diagnostic trouble codes (DTCs) that pinpoint the exact fault.

When to See a Shop:

• Immediately: Since ABS and Traction Control are critical safety systems, you should have your vehicle diagnosed by a Rivian service center or a qualified technician as soon as possible. Driving with these systems disabled can increase your risk of losing control during emergency braking or in slippery conditions. A professional will use specialized diagnostic tools to read the specific fault codes, test the wheel speed sensors, and inspect the ABS module and wiring to accurately identify and repair the problem.