P157A01 - P157A01 Grid Power Outage

Fault Depth Definition

DTC P157A01 is defined as a grid power outage, playing a critical safety monitoring role in the vehicle charging management system. This code indicates that the bidirectional on-board power assembly control unit did not detect a valid external AC power input or control guidance signal. In technical logic, this involves an interruption of the communication feedback loop between the charging interface and the on-board charger. When the control unit cannot confirm the presence of the grid, the system will immediately lock the charging process to prevent high-voltage system misoperation, ensuring the safety of the electrical architecture.

Common Fault Symptoms

Based on the trigger mechanism of DTC P157A01, users may perceive the following phenomena during driving or usage:

• After the vehicle enters a charging connection state, the charging process terminates quickly, unable to maintain current transmission.
• The dashboard charging status indicator light goes off abnormally or displays a charging system fault warning.
• The vehicle display prompts that the grid connection is lost or external power is unavailable.
• HV battery SOC (State of Charge) does not change after connecting charging equipment, with energy inflow interrupted.

Core Fault Cause Analysis

Regarding the generation mechanism of this DTC, attribution analysis can be conducted from the following three technical dimensions:

• Hardware Component Dimension: Abnormal internal circuit within the bidirectional on-board power assembly, or physical terminal damage of the integrated charging port, leading to signal processing function failure.
• Wiring/Connector Dimension: Poor contact or open circuit in low-voltage wiring or connectors, causing control signals to fail transmission; High-voltage wiring or connector failure causing physical interruption of the AC power transmission path.
• Controller & External Dimension: Actual grid power outage event occurring externally, resulting in missing input source; or the control unit confirms independent grid failure under logic judgment without interference from other charging-related faults.

Technical Monitoring and Trigger Logic

The control unit determines this fault through specific sensor data and logic algorithms. The specific monitoring mechanism is as follows:

• Monitoring Target: The system samples real-time AC input side voltage levels, control guidance (CP) signal voltage amplitude, and PWM signal duty cycle.
• Value Thresholds: When the system detects AC side voltage less than $75V$, CP voltage less than $2.5V$, and CP duty cycle equals $0$, it meets the electrical parameter fault judgment criteria.
• Specific Conditions: Fault triggering requires meeting the prerequisite of no other charging-related faults, ensuring accurate identification of dynamic monitoring scenarios for grid power loss or communication link disconnection with composite fault interference excluded.