P1AF300 - P1AF300 DC Charging Cabinet Actively Stops Charging

P1AF300 DC Charging Cabinet Active Stop Charging Fault Technical Diagnostic Description

Fault Definition

During the interaction process between the vehicle's high-voltage electrical system and external energy sources, P1AF300 is a critical diagnostic trouble code (DTC), defined as "DC Charging Cabinet Active Stop Charging". This code reflects the engagement status of the safety protection logic in the vehicle's overall control strategy. When communication handshaking is established with a DC charging pile and pre-charging is completed, if the system detects an unrecoverable high-risk condition, the Control Unit (Controller) will trigger an "Active Stop" command to cut off the high-voltage contactor loop and terminate energy transmission.

This fault involves the coordinated failure or anomaly of three core interaction entities: external power supply infrastructure (DC Charging Pile), vehicle-side high-voltage logic management module (Integrated Intelligent Drive Controller), and on-board energy storage medium (Battery Pack). This DTC not only indicates the interruption of a charging session but also reveals that monitoring thresholds within the High-Voltage Feedback Loop have been triggered. The root cause lies in the system's inability to maintain control parameters that meet safety specifications under dynamic operating conditions, thereby forcing the termination of the charging process to prevent potential electrical safety hazards.

Common Fault Symptoms

Based on the activation logic of this fault code, users may observe the following specific phenomena on driving experience and onboard terminal displays:

• Abnormal Interruption of Charging Session: During normal DC fast charging processes, the charging pile screen or vehicle dashboard suddenly prompts "Charging Pause", "Safety Protection Started", or related error codes, with charging current output instantly returning to zero.
• Instrument Panel Fault Light Activation: A persistent warning signal appears in the vehicle high-voltage system status indicator or dedicated diagnostic information display area, indicating that the control strategy has judged the current environment does not meet continuing power supply conditions.
• Silence After Communication Handshake Failure: An unresponsive state occurs immediately during the pre-charging phase after plugging in the charging cable, causing the charging pile to enter a "Waiting for Connection" mode and unable to establish power transmission.
• Abnormal Historical Recordings: When checking OBDII data streams or backend maintenance logs, frequent voltage fluctuation records, control command timeout feedbacks, or safety latch signals (Safety Latch) will be captured.

Core Fault Cause Analysis

Addressing the triggering mechanism of P1AF300 fault code, technical analysis classifies potential risk sources into the following three dimensions:

• Hardware Component Dimension (DC Charging Pile Failure) Refers to physical performance degradation or electronic module failure of external energy infrastructure. Possible issues include overheating of power semiconductor devices inside the charging cabinet, abnormal increase in output terminal contact resistance, cooling system blockage leading to decreased heat dissipation efficiency, etc., causing irreversible damage at the hardware level that prevents the pile end from providing compliant electrical power output to the high-voltage battery.

• Line and Connector Dimension (Control Link Integrity) Involves low-voltage communication wiring between vehicle and charging pile (such as CAN/LIN bus) or High-Voltage Interlock Loop (HVIL). If cable insulation is damaged, interface terminal oxidation corrosion occurs, or contact pressure is insufficient, monitoring signal voltage drift will occur, packet loss rate increases, and the controller will judge that hardware connection state does not meet safety standards, thereby activating the Active Stop strategy.

• Controller Logic Dimension (Integrated Intelligent Drive Controller Failure) Points to functional errors occurring in the vehicle's internal high-voltage control unit. The Integrated Intelligent Drive Controller serves as a core computing node responsible for parsing charging pile instructions and generating charging waveform parameters. If its internal operation circuits deviate, memory read/write anomalies occur, or program locks up, it may lead to misjudgment of battery voltage, current, and temperature logic, thereby incorrectly issuing stop commands.

• Energy Storage System Dimension (Battery Pack Failure) Involves intrinsic health issues at the high-voltage load end. This includes BMS reported single cell overvoltage/undervoltage warnings, increased risk of thermal runaway, or insulation impedance falling below safety thresholds, forcing the charging system to execute protective disconnection operations to protect battery chemical stability.

Technical Monitoring and Trigger Logic

The generation of this fault code follows a strict control algorithm determination process, with the core being dynamic monitoring of real-time electrical parameters and safety status:

• Monitoring Target Definition The system primarily monitors high-voltage insulation voltage, charging current slope (dI/dt), battery pack SOC/SOH status feedback, and communication protocol checksums between the charging pile and vehicle. All data is updated within a millisecond sampling cycle to calculate real-time safety margin.

• Numerical Range and Safety Thresholds During motor drive or charging processes, key signal voltages monitored by the system usually stay in a high-level stable interval (e.g., $9V$~$16V$ communication reference), while insulation impedance must be maintained at a megaohm level. Once monitoring data deviates from preset safety windows (e.g., instantaneous voltage drop exceeds tolerance, current feedback value deviation from instruction value exceeds threshold percentage), it will be immediately marked as "Abnormal".

• Specific Operating Condition Trigger Logic Fault determination has strong operating condition dependency, only targeting Power Transmission Phase entered after Charging Enable. The system starts deep scanning only upon confirming low-voltage communication link establishment and high-voltage pre-charge completion. If any single fault source (e.g., DC Charging Pile Failure, Controller Logic Error, or Battery Pack Failure) persists during this period and cannot be reset/eliminated at the software level, the control unit will judge it as an irreversible fault condition, subsequently executing "Active Stop Charging" logic and recording the P1AF300 DTC into non-volatile memory.