Jeep ESP and BAS Light On: Causes and Solutions

Understanding the Jeep ESP and BAS Light ON and Code C123F

If you’ve ever been driving your Jeep and noticed the ESP (Electronic Stability Program) and BAS (Brake Assist System) warning lights illuminate on your dashboard, you may be wondering what these indicators mean and how they affect your vehicle’s performance. In this article, we’ll delve into what these systems do, why the warning lights might appear, and what steps you can take if you notice your Jeep ESP and BAS light on.

What Are the ESP and BAS Systems?

Electronic Stability Program (ESP): The ESP is a safety feature designed to help maintain vehicle control during difficult driving conditions, such as when the road is slippery or when you make a sudden maneuver to avoid an obstacle. The system works by monitoring the car’s steering angle, wheel speed, and yaw rate (the vehicle’s rotation around its vertical axis). If it detects that the vehicle is losing control, ESP intervenes by reducing engine power and applying the brakes to individual wheels to help steer the vehicle back on course.

Brake Assist System (BAS): The BAS is another safety feature that works in conjunction with the ABS (Anti-lock Braking System). It is designed to detect emergency braking situations where the driver applies the brakes suddenly and with force. In such scenarios, BAS increases brake pressure to ensure maximum stopping power, helping to reduce stopping distances and potentially prevent accidents.

The Most Common Cause of a Jeep ESP and BAS Light On, Along with a C123F code

If you notice the Electronic Stability Program (ESP) light is on, and a C123F is stored, chances are you’ll need an alignment and a steering angle sensor re-calibration. The steering angle sensor can be knocked out of calibration during service if you turn the wheels by hand instead of turning using the steering wheel.

C123F-STEERING ANGLE SENSOR COMPARATIVE PERFORMANCE

If you have a scan tool, set the wheels to the straight ahead position. The read the steering angle sensor in live data. It should read ±15°. If it does, perform an ECU initialization (if your scan tool has that feature.

If not, get an alignment.

©, 2022 Rick Muscoplat