• ABS warning light on
• Traction control light on
• Loss of ABS functionality
• Faulty ABS control module
• Damaged wiring or connectors
• Faulty CAN bus network
ABS: Anti-lock Braking System
ECU: Engine Control Unit
CAN bus: Controller Area Network bus
• U0122
• U0123
This code means your car's computer is having trouble talking to the brakes. It's like when your phone can't connect to the internet.
The U0121 code indicates a loss of communication with the Anti-lock Brake System (ABS) control module.
U0121 is a diagnostic trouble code (DTC) that indicates a failure in the communication network between the vehicle's main computer (ECU) and the Anti-lock Brake System (ABS) control module. This can result in the inability of the ABS to function properly, as the necessary data exchange is interrupted.
• Check for other related codes
• Inspect ABS module wiring and connectors
• Test the CAN bus network for continuity
• Repair or replace damaged wiring
• Replace faulty ABS control module
• Ensure proper connection of all connectors
• OBD-II scanner
• Multimeter
• Wiring diagram
$150 - $1000
Moderate
• Ford F-150
• Chevrolet Silverado
• Toyota Camry
• Regularly inspect wiring for damage
• Keep connectors clean and secure
• Have the ABS system checked during routine maintenance
Communication Error
• Do not ignore the ABS warning light
• Have a professional diagnose the issue
• Avoid driving in conditions where ABS is crucial
Check with your vehicle manufacturer for warranty coverage on the ABS module.
U0121 has been a common code in vehicles equipped with advanced electronic systems since the early 2000s.
Moderate – While the vehicle may still be drivable, the ABS system is compromised, affecting safety.
Driving with a malfunctioning ABS system can lead to reduced braking performance, especially in slippery conditions. It is advisable to address this issue promptly.
• Vehicle in park
• Ignition in ON position
The ABS control module is typically located near the brake master cylinder or within the engine compartment.
Q: Can I drive with a U0121 code?
A: While you can drive, it's not recommended as your ABS system may not function properly, affecting braking safety.
Q: Will clearing the code fix the problem?
A: Clearing the code might turn off the warning light temporarily, but if the underlying issue isn't fixed, the code will likely return.
