A common issue on BMW motorcycles, particularly the R1200RT, is the dreaded brake fault light. This often points to a problem with the ABS system, and specifically, the power supply to the ABS pump motor. While a diagnostic tool like the GS-911 can pinpoint the error code (often “24048: Power Supply to Pump motor faulty”), the underlying cause can be elusive. This article explores troubleshooting steps and potential solutions for Abs Power Supply problems on a BMW R1200RT.
Diagnosing the ABS Power Supply Fault
When the GS-911 indicates a fault with the ABS pump motor power supply, the first step is to verify the motor itself. Disassembling the ABS pump and checking the motor’s resistance using a multimeter is crucial. A reading of 5-6 ohms between the pins is typically normal. Furthermore, connecting the motor directly to a 12V power source should cause it to rotate smoothly. If the motor functions correctly, the problem likely lies elsewhere in the power supply circuit.
Potential Causes and Solutions
While a faulty ABS pump motor is possible, other factors related to the ABS power supply can trigger the fault code. These include:
Battery Issues:
A weak or failing battery, despite showing a resting voltage of 12.65V, can cause intermittent ABS faults. While the alternator may output the correct voltage (14.4V) while running, a battery unable to hold a charge under load can disrupt the power supply to the ABS system. Replacing the battery with a new, reliable unit, such as a gel battery, is a recommended troubleshooting step.
Wiring and Connections:
Corrosion, loose connections, or damaged wiring within the ABS power supply circuit can also interrupt power to the pump motor. Thoroughly inspecting all connections and wiring harnesses related to the ABS system is crucial. Cleaning connections and repairing or replacing damaged wires may resolve the issue.
ABS Control Module:
In rare cases, a malfunctioning ABS control module can cause power supply problems. However, this is usually a diagnosis of exclusion after other potential causes have been eliminated.
Fuse or Relay:
A blown fuse or faulty relay in the ABS power supply circuit can prevent power from reaching the pump motor. Checking the relevant fuses and relays and replacing any defective components is a simple but important step.
Conclusion
Troubleshooting an ABS power supply fault on a BMW R1200RT requires a systematic approach. Start by verifying the ABS pump motor’s functionality. If the motor is operational, focus on potential issues with the battery, wiring, connections, and related components like fuses and relays. While replacing the entire ABS pump unit is an option, it’s often more cost-effective to explore and address the underlying power supply problem first. Remember, a properly functioning ABS system is crucial for rider safety.
