Drive Motor "A" Performance
The P0A90 code means the vehicle's onboard diagnostic system has detected: Drive Motor "A" Performance. This is a serious severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- hard
- Estimated cost
- $300 - $4,500 (sensor or wiring causes at the low end; motor or transaxle service at the high end - diagnose first)
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Common Symptoms
- Check Engine Light and hybrid system warning on
- Reduced electric assist or EV operation disabled
- Vibration or noise from the transaxle under electric load
- Reduced fuel economy as the engine covers for the motor
Probable Causes (Ranked by Likelihood)
- Drive Motor "A" winding degradation or internal fault High
- Position or current sensor fault degrading motor control High
- Inverter fault limiting the motor Moderate
- Mechanical problem in the transaxle loading the motor Low
Frequently Asked Questions
What does P0A90 mean?
P0A90 means the Drive Motor "A" is underperforming against what the control module commands - from winding wear, a sensor problem, or an inverter limitation.
Can I keep driving with P0A90?
Short distances. The system usually compensates with the engine, but the underlying fault can worsen and take more expensive components with it.
Is P0A90 safe to work on myself?
This code involves the high-voltage system. Do not open the HV battery, inverter, or any orange-cabled component without hybrid-specific training, insulated gloves, and the service plug removed. Diagnosis beyond a scan-tool read belongs at a hybrid-qualified shop.
Mechanics Guide Step-by-step diagnosis
Step-by-Step Diagnostic Procedure
-
Read all companion codes - sensor and inverter faults frequently masquerade as motor performance complaints.
-
Compare commanded versus actual torque/speed for the Drive Motor "A" on a road test.
-
With the HV system verified de-energized, test motor winding resistance and insulation per the OEM procedure.
-
Rule out the cheap causes (sensors, connectors, cooling) before any motor or transaxle work.
Sources 1
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
Commonly Affected Vehicles
- Toyota/Lexus hybrids (Prius, Camry Hybrid, RAV4 Hybrid)
- Ford/Lincoln hybrids (Escape, Fusion, C-MAX)
- Honda hybrids (Insight, Civic Hybrid, Accord Hybrid)
- Hyundai/Kia hybrids and plug-in hybrids
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