AI suggests the following
An ABS warning light on a 2021 Morgan Plus Four is most commonly triggered by a dirty or faulty wheel speed sensor, low brake fluid, a blown ABS fuse, or a wiring issue.
Because these cars use a modern BMW powertrain and electronics, the system can also log an error due to a dying battery or a faulty brake light switch.
Common Causes and Checks
Wheel Speed Sensors:
These are located at each wheel hub and monitor rotation. Because Morgan Plus Fours are open-wheel style and sit close to the road, dirt, mud, and road debris can easily foul a sensor or its wire, breaking the signal to the ABS control module.
Brake Fluid Reservoir:
Check your brake fluid level. If the fluid is low (often due to worn brake pads or a slight leak), the system may disable the ABS and illuminate the light
.Fuses and Relays:
A blown fuse or a faulty relay can cut power to the ABS pump or module.
Battery/Voltage Fluctuations:
Modern Morgans utilize sensitive electronics. If your battery voltage drops too low during starting, it can trigger an ABS or stability control warning code.
Brake Light Switch
: If the switch behind your brake pedal fails, it can confuse the ABS/traction control module, causing the warning light to turn on.
What to Do Next
Check for debris: Look behind your wheels and gently clean off the speed sensors and their wiring. Check for loose connections.Verify fluid levels: Ensure your brake fluid is at the correct level.Use an OBD2 Scanner: Because of the shared BMW electronics platform, you can often retrieve specific ABS fault codes by plugging an OBD2 scan tool into the port located under the dashboard. This will pinpoint exactly which sensor or valve is causing the issue
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