P0A1F on Mercedes-Benz
Motor Generator B - Performance
P0A1F on Mercedes-Benz vehicles indicates motor generator b - performance. Au7o has documented this code across 1 Mercedes-Benz model — most commonly on EQS SUV. In standard usage this hybrid code corresponds to 'Battery Energy Control Module Performance,' meaning the module that manages the high-voltage battery failed an internal performance or self-test check. This control module monitors the hybrid battery pack's charge, temperature, and cooling, and runs internal integrity checks on its own memory and processing. When those checks don't meet specification, the code is set, and it usually points to an internal module fault rather than the battery cells themselves. Expect a hybrid warning light and possibly reduced electric assist or readiness.
Common Causes of P0A1F
- •Internal fault within the battery energy control module
- •Software/calibration corruption in the module
- •Damaged wiring or connectors at the module
- •Poor power or ground supply to the module
- •Low 12V (auxiliary) battery voltage
- •Moisture/corrosion intrusion at the module
- •Faulty hybrid battery pack sensor inputs
P0A1F on Mercedes-Benz by Model
Mercedes-Benz EQS SUV(1 issue)
- Battery Management System Diagnostic Memory Overflow Opens HV Contactors (Turtle Mode)2023-2025
Other control units on the EVA2 bus continuously send diagnostic requests to the high-voltage battery management system. The BMS memory overflows, the module shuts down, and the HV contactors open - disconnecting the 108 kWh pack from the drive unit. The result is an instant loss of propulsion at speed with the red turtle icon on the display, even with a nearly full state of charge. NHTSA recall 24V-372 covered 14,912 EQE/EQS sedans and SUVs, and owners reported the failure occurring on freeways before the fix.
Looking for P0A1F on a different make?
View P0A1F across all makes →Frequently Asked Questions
What does P0A1F mean on Mercedes-Benz?▼
P0A1F stands for "Motor Generator B - Performance." In standard usage this hybrid code corresponds to 'Battery Energy Control Module Performance,' meaning the module that manages the high-voltage battery failed an internal performance or self-test check. This control module monitors the hybrid battery pack's charge, temperature, and cooling, and runs internal integrity checks on its own memory and processing. When those checks don't meet specification, the code is set, and it usually points to an internal module fault rather than the battery cells themselves. Expect a hybrid warning light and possibly reduced electric assist or readiness. On Mercedes-Benz specifically, this code is documented across 1 model.
What causes P0A1F on Mercedes-Benz vehicles?▼
Common causes on Mercedes-Benz: Internal fault within the battery energy control module, Software/calibration corruption in the module, Damaged wiring or connectors at the module, Poor power or ground supply to the module, Low 12V (auxiliary) battery voltage. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0A1F on a Mercedes-Benz?▼
Repair costs vary widely depending on the root cause and specific Mercedes-Benz model.
Which Mercedes-Benz models have P0A1F documented?▼
Au7o has documented P0A1F on 1 Mercedes-Benz model: EQS SUV.