P1AD900 - P1AD900 Charging Port Temperature Sampling Point Abnormality (EU Standard 7kW)

P1AD900 Fault Definition

P1AD900 serves as a critical fault code within the onboard electrical diagnostic system, specifically used to identify abnormal states in the temperature monitoring circuit of the charging interface. Under the European Standard 7kW AC charging architecture, this control unit is responsible for real-time acquisition of thermal parameters at both AC and DC charging ports to ensure high-voltage connection parts remain within safe thermal management zones. The core definition of this fault code lies in anomaly in signal feedback of the temperature sampling point, meaning the physical signals read by the integrated intelligent controller cannot accurately map the actual ambient temperature. Activation of this code directly reflects a potential risk in interface thermal status judged by the vehicle BMS (Battery Management System) or charging management subsystem, aiming to prevent electrical safety accidents caused by overheating.

Common Failure Symptoms

When the system records and stores the P1AD900 fault code, user-vehicle interaction is primarily limited by the activation of safety protection strategies. Based on the control unit's logic judgment, typical driving experience or instrument feedback includes:

• Charging Function Blockage: The vehicle cannot establish a connection or suddenly interrupts AC/DC charging processes; OBC (On-Board Charger) stops supplying power to the battery pack.
• Discharge Restricted State: If the system is in external discharge mode, the vehicle may refuse to output electricity due to activated temperature protection strategies to ensure safety.
• Fault Indicator Warning: Charging system related warning lights may illuminate on the dashboard or APP, prompting drivers to pay attention to interface temperature anomaly risks.
• Communication Link Interruption: During the charging handshake protocol (CP/PP) establishment process, it may manifest as connection failure or repeated error reporting after reconnection due to unreliable sampling signals.

Core Failure Cause Analysis

Regarding fault determination for P1AD900, technical logic summarizes root causes into anomalies at three dimensions: physical hardware, wiring connections, and control calculation:

• AC/DC Charging Port Fault (Hardware Component Layer): Refers to damage occurring to the physical interface module itself located outside the vehicle body. This may include built-in temperature sensor component failure, poor contact, or internal temperature measurement chip short/open circuit phenomena, leading to an inability to collect valid thermal data.
• AC/DC Charging Port Temperature Sampling Harness Fault (Wiring and Connector Layer): Physical hazards exist in the signal transmission path connecting sensors and controllers. This includes short circuits caused by wire insulation layer damage, ground interference, connector pin oxidation loosening, or harness internal breaks, causing distorted or lost temperature data during transmission.
• Integrated Intelligent Controller Front-Drive Fault (Controller Logic Layer): Internal electronic control units responsible for parsing temperature signals may experience software logic errors or hardware computation anomalies. Even if external sensor signals are normal, if the controller cannot correctly perform Analog-to-Digital Conversion (ADC) or algorithmic judgment logic errors, this fault code may be falsely reported.

Technical Monitoring and Trigger Logic

The system follows strict safety strategies for monitoring charging port temperature, with its trigger mechanism based on dynamic analysis of real-time data streams:

• Monitoring Target: The system continuously monitors the actual working temperature of AC/DC charging ports, focusing on heat accumulation at high-voltage terminal connections to ensure thermal safety compliance under 7kW power transmission conditions.
• Numerical Threshold Judgment: Through internal calibration algorithms, the system converts collected analog signals into digital temperature values. Only when this value exceeds a predefined specified threshold (Specified Threshold) will the fault determination process be entered. This threshold setting is typically based on material heat resistance limits and insulation performance requirements.
• Operating Condition Trigger Conditions: Fault monitoring primarily occurs during charging, discharging, or when the vehicle is in high-voltage power-on state. Once the control unit's real-time calculated temperature signal $T_{actual}$ continuously exceeds the preset safety upper limit value $T_{limit}$, the system immediately determines "Charging Port Temperature Sampling Point Abnormality" and generates P1AD900 fault code, while executing safety protection strategies to cut off or limit power output.