C05C24B - C05C24B Brake Booster Motor Temperature High

Detailed Fault Definition

C05C24B Fault Code (Brake Booster Motor Temperature Too High) is a critical diagnostic signal for the Intelligent Power Brake System. In vehicle electronic architecture, this fault code aims to monitor the thermal management status of the drive motor, ensuring physical stability of actuators under high-voltage or high-load conditions. When the control unit detects internal heat accumulation in the brake booster motor exceeding preset safety limits, this definition is triggered. This code directly links to the generation and control logic of hydraulic assist pressure and serves as a foundational feedback loop for braking performance. If this signal fails, the system cannot precisely match the driver's pedal intent with actual output torque.

Common Fault Symptoms

Based on the original description of Partial Function Failure of Intelligent Power Brake System and vehicle control logic analysis, when C05C24B is illuminated, owners or technicians may observe the following phenomena:

• Abnormal Driving Experience: Due to limited motor output, pedal travel distance may increase, brake foot feel becomes softer, leading to a significant reduction in power assist effect.
• Dashboard Warning Indicators: The vehicle dashboard fault warning lights (such as ABS, IPB system light or engine warning light) will illuminate, indicating electronic control system anomalies.
• System Status Lockout: Under extreme thermal protection logic, the vehicle may automatically limit motor output power and enter limp mode to prevent physical damage.

Core Fault Cause Analysis

For root cause troubleshooting of DTC C05C24B, according to the original data "Internal fault in Intelligent Power Brake Controller", we categorize the failure mechanism into the following three technical dimensions for analysis:

• Hardware Components (Intelligent Power Brake Controller): This is the core direction of the current diagnosis. Original data shows the fault is located inside the integrated electronic hardware of the controller, not the external independent motor body itself. This usually means that thermal runaway or circuit physical damage has occurred within the drive power stage circuit, built-in temperature sensor IC, or power management module of the controller.
• Lines/Connectors (Physical Connection): Although the fault code points to the controller, in troubleshooting logic, it is necessary to confirm whether there is poor contact causing heat loss between the communication and power supply lines between the controller and the motor. However, given that the original cause is clearly "internal fault", the possibility of wiring issues is low at this diagnostic level.
• Controller (Logic Operation): If the firmware algorithm inside the control unit cannot correctly parse the temperature feedback signal from the motor, or if there are deviations during signal calibration processes, this code will also be triggered. This belongs to electronic logic operation anomalies inside the hardware component.

Technical Monitoring and Trigger Logic

The generation of this fault code follows strict automotive network diagnostic protocols, with its judgment logic based on the following monitoring mechanisms:

• Monitoring Target: System continuously reads real-time feedback data from the brake booster motor temperature sensor (voltage/current signal converted to temperature value).
• Value Range Judgment: Although specific threshold parameters are not given, the trigger condition starts logical locking when the measured temperature exceeds the overheat protection upper limit ($T_{limit}$) set inside the controller.
• Fault Trigger Condition: Fault judgment begins initialization monitoring only when "Ignition Switch Placed in ON Position". Once ignition is on, ECU immediately activates self-check program for motor thermal status; if abnormal high temperature is detected at this time, it is considered an effective fault event.