OBD-II trouble code
P0A94: DC/DC Converter Performance
Application matters: The dated Toyota examples are a 2006 Highlander HV field case and T-SB-0003-21 Rev1 for listed 2010–2015 Prius and 2012–2017 Prius v vehicles. Keep each vehicle, full code and information code with its own procedure.
The converter-performance report needs the complete manufacturer diagnosis. Toyota examples show different repair scopes, so neither a whole inverter nor a hybrid battery can be selected from P0A94 alone.
Quick facts
- System
- Powertrain
- Category
- Hybrid Propulsion
- Severity
- High severity
- Driving guidance
- Stop safely and arrange diagnosis
- Repair cost range
- Get a vehicle-specific estimate after diagnosis.
- DIY difficulty
- Shop recommended
A code alone cannot establish whether driving is safe. Stop safely for a red brake or oil-pressure warning, overheating, severe misfire, stalling, or impaired braking or steering, and follow the owner's manual. Restraints faults can reduce crash protection even when the vehicle runs normally.
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What does P0A94 mean?
P0A94 identifies a DC/DC converter performance condition. The complete vehicle-specific report determines which function and diagnostic path are involved. Do not reduce the title to an automatic low-voltage battery repair, a conventional charging-system diagnosis or a finding that the whole inverter must be replaced.
Toyota’s May 27, 2008 field report documents P0A94 alongside P0A78, P0A7A and brake-related companion codes on a 2006 Highlander HV. That vehicle could enter READY but would not move as expected. The technician used the P0A78 Repair Manual path and identified an inverter-with-converter fault. This is a particular multi-code case, not proof that every P0A94 has that cause or that READY establishes reliable propulsion.
A separate example, Toyota T-SB-0003-21 Rev1 dated February 16, 2023, covers its listed Prius and Prius v applications. It supersedes the earlier T-SB-0036-16 and directs different repair paths depending on the specified physical-damage finding. For an undamaged assembly, component selection depends on the inverter type, full DTC and information code. That process is for qualified personnel, not an owner inspection or a reason to order every part in the bulletin’s reference list.
Ask the repairer to identify the exact converter/inverter configuration and explain the finding that supports component-level work or an assembly repair. Neither the generic performance label nor a companion code proves that the battery, wiring or control electronics are healthy. Those conclusions require the actual diagnostic results.
Record warnings and symptoms before clearing. Do not repeat starts, attempt a driving test or open an inverter cover to investigate. High-voltage shutdown, verification, electrical tests and repair belong with trained hybrid service. Follow the vehicle’s recovery guidance and arrange assistance when propulsion is unreliable or a stop warning is present.
Possible causes
- An inverter-with-converter fault established in the documented Highlander case
- A component or assembly condition identified through the matched Prius bulletin and full DTC/information-code selection
- Another converter-performance fault confirmed by the actual vehicle procedure
Symptoms
- A malfunction indicator or hybrid warning with P0A94
- Reduced or unavailable propulsion if the actual fault affects the vehicle
- READY indication without normal movement in the documented Highlander case
Diagnostic steps
Save the full scan report, code status, and available freeze-frame data before clearing anything. Confirm the reporting module, any failure-type suffix, and the procedure for the exact vehicle. The steps below are an overview; use manufacturer specifications and safety procedures for testing.
- 1.Save the full scan, information codes, companion faults and current warning messages before clearing anything. Report READY and propulsion behavior already observed.
- 2.Arrange qualified hybrid diagnosis for the actual model, engine/system and complete fault report. Do not infer a repair from the five-character title.
- 3.Have any applicable service bulletin matched to the vehicle. The Highlander field case and Prius bulletin describe different applications and cannot be used interchangeably.
- 4.For the listed Prius example, have qualified personnel apply the specified damage assessment or the undamaged-assembly identification path. Do not remove covers or inspect high-voltage components yourself.
- 5.Request the confirmed repair scope and required verification. Do not use code clearing, a battery swap or an owner road test as evidence that the converter fault is corrected.
Repair cost
Get a vehicle-specific estimate after diagnosis.
A trouble code alone does not price the repair. Ask the shop to identify the confirmed fault and itemize diagnosis, parts, labor, programming or calibration, and taxes.
Estimate your repair
Run the numbers for your vehicle
Open the Repair Cost Estimator with qualified hybrid-system diagnosis preselected. Adjust labor rate and vehicle category to fit your situation.
Related repairs
These links are planning examples; the code does not confirm that any listed part has failed.
DIY vs shop
A qualified shop is recommended because this can involve a high-voltage traction system that stays live with the car switched off and requires documented shutdown procedures, in-date insulating gloves, and specific training. Ask the technician what testing confirmed the repair.