U01F287 - U01F287 Lost Communication With IPB

Communication Loss with IPB: Fault Depth Definition

DTC U01F287 identifies a severe link interruption in the vehicle communication network. The core of this fault code is an abnormality in data interaction between the Intelligent Power Brake (IPB) controller and the control bus, causing the system to fail to obtain necessary status messages. In the vehicle architecture, IPB as part of a key actuator, is responsible for processing complex braking logic and signal execution. The appearance of U01F287 means that the network communication node inside the control unit failed to receive expected data frames, which not only affects the coordinated work of the braking system but also affects additional safety systems relying on IPB data links, such as Blind Spot Monitoring (BSM). This fault code reflects a failure in the message reception mechanism within the underlying network protocol stack, rather than simple signal interference.

Common Fault Symptoms

When the control unit detects communication interruption with the IPB, the following driving experience or instrument feedback may become abnormal:

• Limited Blind Spot Monitoring Function: Due to inability to obtain key status signals, blind spot monitoring functions are partially disabled, potentially manifested as off side approaching vehicle warning lights, audio prompts stopping or system icons disabled.
• Dashboard Warning Indicator: Driver might see braking system or body electronic related fault indicator lights on the combination instrument panel lit up, indicating potential safety risks.
• Abnormal Dynamic Monitoring Status: Under specific vehicle speed or operating conditions, auxiliary driving functions that should link work together may fail to enter normal working mode, and system logs will record communication timeout records.

Core Fault Cause Analysis

Based on raw data analysis, the root causes leading to DTC U01F287 are primarily concentrated in the following three dimensions:

• Hardware Component Anomaly: The electronic unit of the Intelligent Power Brake Controller (IPB) itself may experience logical errors or internal communication chip damage, leading to an inability to correctly respond to bus wake-up signals.
• Circuit and Connector Physical Connection: Wiring between control unit and IPB may have open circuits, short circuits, or connectors due to oxidation, loosening causing excessive contact resistance, resulting in data frame loss.
• Power Supply System Status: A fuse supplying power to the controller may blow or age out, resulting in the working voltage supplied to the IPB falling below the normal maintenance threshold, thereby interrupting the communication link.

Technical Monitoring and Trigger Logic

The control unit's execution of DTC U01F287 set conditions involves strict numerical thresholds and timing logic to ensure fault determination accuracy:

• Monitoring Target: The system monitors a specific message stream from the IPB in real-time, focusing on detecting continuous loss of any monitoring message.
• Trigger Determination Count: When the control unit detects any monitoring message lost continuously 10 times within a diagnostic session, it satisfies the preliminary condition for fault setting.
• Voltage Range Limitation: The controller monitors this signal only within the normal operating voltage range, specifically $9V$~$16V$. Extreme conditions exceeding this range will not trigger this specific code, but are classified as other power-related faults.
• Timing and State Logic: Fault triggering must simultaneously satisfy the following dynamic conditions:
  1. Timing for monitoring begins $3s$ after vehicle power-on initialization is complete;
  2. The Private CAN bus link has not entered Bus-off protection status, indicating the physical connection has not completely disconnected;
  3. The system is currently in normal application mode, and factory mode is disabled, excluding test environment interference.