P157A01 - P157A01 Power Grid Power Failure

P157A01 Deep Analysis of Grid Power Outage Fault

### H3 Fault Depth Definition

DTC P157A01 (Grid Power Outage) is defined as an abnormal state of external energy supply interruption in the new energy vehicle charging management system. This fault code is primarily generated by the Integrated Smart Propulsion Controller to monitor the integrity of the high-voltage charging loop and power supply continuity in real-time. When the system detects expected AC supply voltage disappearance or unexpected power-off events, the control unit judges this as a grid power outage event. This definition covers a wide range from external environmental factors (such as utility power interruption) to internal electrical architecture (such as signal loss due to high-voltage wiring insulation failure), aiming to ensure the battery management system can safely cut off the charging loop after losing external charging energy input, preventing equipment damage or safety accidents.

### H3 Common Fault Symptoms

When vehicle P157A01 code is activated, drivers can perceive system abnormal response via:

• Charging Interruption: After entering normal charging state, charging process is forcibly terminated in a very short time.
• Indicator Light Status Change: Charging indicator on dashboard or central screen changes from constant-on to off or flashing, showing non-connected/non-charging state.
• Screen Prompts: Vehicle HMI may pop up warnings like "Charging Abnormal", "Grid Power Outage", or "Please Check External Power".
• Power Fluctuation: At fault instant, high-voltage system input power monitoring value may drop abruptly to zero.

### Core Fault Cause Analysis

According to diagnostic data logic, core reasons for P157A01 activation classified into three technical dimensions:

• External Environment and Grid Factors: Direct cause is Grid Power Outage. When utility power interrupts, high-voltage charging port cannot get input voltage, controller immediately judges grid-side supply failure.
• Physical Lines and Connector Connections: High Voltage Charging Line Insulation Failure or AC Charging Port Fault. Hardware level physical damage, e.g., wire insulation layer damaged causing leakage signals misjudged as power loss, or charging port pin corrosion/poor contact preventing power transmission to control unit.
• Electronic Control Logic Failure: Integrated Smart Propulsion Controller Failure. As system logic core, if internal voltage sampling circuit damaged or logic erroneous, system may incorrectly judge normal supply as outage.

### H3 Technical Monitoring and Trigger Logic

Vehicle charging control system follows strict diagnostic strategies to confirm P157A01 activation conditions:

• Monitoring Target: Controller monitors High Voltage Sustained Power Loss events (High Voltage Sustained Power Loss). System tracks external AC voltage existence during charge status and stability.
• Trigger Prerequisite Conditions: Fault judgment executed only after charging status confirmed correctly. System must detect plug-in confirmation signal normal establishment and BMS accepts charging request first.
• Fault Judgment Operating Conditions: System observes high voltage sustained power loss after charge start. Momentary fluctuation with recovery won't trigger; voltage suddenly drops from high level and sustains for period recorded as grid outage.
• Exclusive Logic: Requires satisfying no other charging-related faults. If P06xx communication faults or battery protection faults exist simultaneously, system enters higher-level protection mode ignoring simple grid loss judgment. Ensures accurate fault localization, avoids complex systemic faults classified as external outage.