P0A1A: Motor Generator A - Performance
6 vehicles · 1 makes · $200-$6,500 repair
Most Reported On
P0A1A is an OBD-II diagnostic trouble code meaning “Motor Generator A - Performance.” This is a hybrid/electric powertrain code indicating a performance problem with motor-generator 'A' — typically the generator portion of the hybrid drive that produces electricity and helps start the engine. The hybrid control system monitors this motor-generator and its control electronics (inside the inverter assembly), and sets this code when the unit doesn't perform as commanded. It often points to a fault in the motor-generator control circuit, a current sensor, or the inverter/intelligent power module. You'll usually see a warning light and may experience reduced hybrid performance or a disabled hybrid system. This code is most commonly reported on 2021-2025 Mercedes-Benz S-Class (S500, S580), 2020-2025 Mercedes-Benz GLS (GLS450, GLS580), and 2019-2025 Mercedes-Benz AMG GT 4-Door (AMG GT 43, AMG GT 53, AMG GT 63 S E Performance), plus 3 other vehicles, with repair costs ranging from $200 to $6,500.
Common Causes
Typical Repair Cost
Based on 6 documented vehicle-specific issues. Actual cost depends on root cause and vehicle.
Diagnostic Tools
To diagnose P0A1A, you'll need an OBD-II scanner. Here are our recommendations at every price point.
ANCEL AD310 Classic OBD-II Scanner
by ANCEL
A simple, affordable code reader that reads and clears check engine codes. Great for quick diagnostics on any OBD-II vehicle (1996+).
- Read & clear engine codes
- View freeze frame data
- I/M readiness status
- No batteries or app needed
BlueDriver Pro Bluetooth Scanner
by BlueDriver
Bluetooth OBD-II scanner with a free companion app. Provides enhanced diagnostics, smog readiness, and repair reports sourced from a database of verified fixes.
- Enhanced diagnostics (ABS, SRS, transmission)
- Repair Reports with verified fixes
- Smog check readiness
- Free app (iOS & Android)
LAUNCH CRP123X OBD-II Scanner
by LAUNCH
A professional-grade handheld scanner that reads all four major systems (engine, transmission, ABS, SRS) with live data streaming and graphing.
- Engine, transmission, ABS, SRS diagnostics
- Live data stream & graphing
- AutoVIN for vehicle identification
- Free lifetime updates via Wi-Fi
Autel MaxiCOM MK808S Diagnostic Tool
by Autel
Shop-level diagnostic tablet with bi-directional control, active tests, and full system coverage. Ideal for serious DIYers and small shops.
- All-system diagnostics (25+ modules)
- Bi-directional control & active tests
- Oil reset, EPB, BMS, TPMS, injector coding
- 7-inch touchscreen with Android OS
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Vehicles Affected (6)
48V Mild Hybrid Battery Issues
Battery Drain from 48V System
48V Mild-Hybrid Battery Degradation and Faults
48V Integrated Starter-Generator / DC-DC Converter Failure Causing Sudden Power Loss and No-Restart
48V Mild-Hybrid / Integrated Starter-Generator Failure Causing No-Start and Power Loss
48-Volt Integrated Starter-Generator / DC-DC Converter Failure Causing Warning Messages, Limp Mode, or No Restart
FAQ
What does P0A1A mean?
P0A1A stands for "Motor Generator A - Performance." This is a hybrid/electric powertrain code indicating a performance problem with motor-generator 'A' — typically the generator portion of the hybrid drive that produces electricity and helps start the engine. The hybrid control system monitors this motor-generator and its control electronics (inside the inverter assembly), and sets this code when the unit doesn't perform as commanded. It often points to a fault in the motor-generator control circuit, a current sensor, or the inverter/intelligent power module. You'll usually see a warning light and may experience reduced hybrid performance or a disabled hybrid system.
What are the most common causes of P0A1A?
The most common causes of P0A1A are: Faulty motor-generator (MG) control circuit or current sensor in the inverter, Failed inverter / intelligent power module (IPM), Damaged or shorted high-voltage motor wiring or connectors, Internal fault in motor-generator A, Corroded or loose control-circuit connectors, Outdated or corrupted hybrid control software, Faulty hybrid/motor-generator control module (ECU). The specific cause varies by vehicle.
How much does it cost to fix P0A1A?
Repair costs for P0A1A range from $200 to $6,500, depending on the vehicle and root cause.
Which vehicles are affected by P0A1A?
Au7o has documented P0A1A across 6 vehicle models from 1 manufacturers: Mercedes-Benz.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.