P157A01 - P157A01 Power Grid Power Outage

Fault Depth Definition

P157A01 Grid Power Outage (Grid Power Outage) is a key fault code used in electric vehicle energy management systems to identify external AC power supply environmental anomalies. At the vehicle architecture level, this code reflects the real-time monitoring results of the integrated intelligent rear-drive controller on input power status. Its core role is to execute safety interlock logic during the charging process, that is, when the controller detects that the upstream AC grid side voltage level falls below the preset safety threshold or the communication signal chain is interrupted, the system judges it as a "Grid Power Outage" state. This fault code is not only a signal indicator of energy cut-off, but also an important feedback mechanism for the vehicle BMS and VCU to work collaboratively to protect the high-voltage battery pack from abnormal power surges. This definition covers comprehensive diagnosis of AC charging port assembly, harness network, and controller internal voltage monitoring circuits.

Common Fault Symptoms

When the system detects a grid power outage state meeting set conditions, the vehicle end will present the following perceptible driving experience and instrument feedback phenomena:

• Unexpected Interruption of Charging Process: The vehicle has already confirmed entering charging ready state, but charging power transmission stops rapidly before reaching expected battery level and cannot be recovered.
• Abnormal Lighting of Dashboard Fault Lights: Charging indicator light or power management warning light on the driver side dashboard turns from solid on to off or displays specific fault icons during charging process.
• OBC Communication Link Interruption Feedback: The handshake protocol between On-Board Charger (OBC) and external charging pile is forcibly terminated, system records as abnormal disconnection event on power side.

Core Fault Cause Analysis

For P157A01 fault code, based on original data divide its root cause into following three dimensions for technical analysis:

1. Hardware Components

   • External Grid Environment: Physical power outage or voltage source failure occurs in external public AC grid.
   • AC Charging Port Assembly: Electrical contact poor within the vehicle front-end AC charging interface, leading to power unable to be imported into OBC internal detection circuit.

2. Wiring and Connectors

   • Low Voltage Harness Network: Low voltage harness responsible for transmitting CP (Control Pilot) signal occurs open circuit, short circuit or impedance too high, resulting in signal voltage loss.
   • High Voltage Harness System: Strong current harness connecting grid inlet to controller internal insulation damaged or connector loose, causing physical level connection failure.

3. Controller and Logic Operation

   • Integrated Intelligent Rear-Drive Controller: Analog front end circuit inside the controller responsible for collecting AC side voltage drifts, or its internal diagnostic algorithm misjudges input signals. This component executes final fault judgment logic.

Technical Monitoring and Trigger Logic

System dynamically scans electrical parameters during charging process through integrated intelligent rear-drive controller's real-time sampling module. Only when strict conditions are met in specific operating conditions will P157A01 fault code be locked and stored.

Monitoring Target Details:

• AC Side Voltage: Controller monitors voltage amplitude at grid input end in real time, judged abnormal when signal persists or instantly falls into $< 75\text{V}$ threshold interval.
• Control Pilot Voltage: CP pin level responsible for charging handshake protocol is pulled down continuously, monitoring system detects CP voltage less than $2.5\text{V}$.
• Signal Duty Cycle (CP Duty Cycle): CP signal waveform duty cycle detection value used for synchronization in communication protocol is fixed zero value ($0$), indicating no effective communication pulse feedback.

Specific Constraints of Triggering Fault Conditions: System requires meeting "no other charging related fault" clean background condition when executing fault locking logic. This means only under confirmation of no charging pile communication faults, battery internal protection lock or other power management errors exists, above-mentioned voltage and signal combination parameters will be recognized as exact "Grid Power Outage" state, thereby formally triggering this DTC storage and stopping current charging energy transmission process.