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DTC codes / P0Exx · Hybrid propulsion / P0E94

P0E94Drive Motor B Inverter Voltage Sensor B Circuit

P0E94 indicates that the inverter for drive motor B has detected an abnormal voltage reading on its sensor B circuit, which typically monitors a specific phase or internal bus voltage. The computer compares this signal against expected values and sets the code when the voltage falls outside the calibrated range or the circuit integrity is compromised.

SystemPowertrain
Code typeGeneric (all makes)
SeverityHigh
Fix difficultyProfessional
AreaHybrid propulsion

Symptoms you may notice

  • Illumination of the hybrid or electric vehicle warning light, often accompanied by a reduced power message.
  • The vehicle may enter a fail-safe mode that limits motor output or prevents the use of drive motor B entirely.
  • Intermittent loss of propulsion or a sudden drop in power while accelerating.
  • Audible warning chimes or a message to pull over safely due to a high-voltage system fault.
  • Often no symptoms besides the warning light, especially if the fault is stored but not currently active.

Common causes, most likely first

  1. A damaged or chafed wire in the voltage sensor B circuit, often due to vibration or heat exposure.
  2. Corrosion or poor pin tension at the inverter connector for the sensor B signal or ground circuit.
  3. Failure of the voltage sensor B itself inside the inverter assembly, leading to erratic or out-of-range readings.
  4. Internal inverter fault, such as a failed sensing circuit board or a problem with the motor B phase voltage measurement.
  5. A weak or failing 12-volt auxiliary battery causing low reference voltage to the inverter electronics.
  6. High-voltage cable or connector issues that introduce electrical noise or intermittent opens in the sensor circuit.

How to diagnose and fix it

  1. Connect a scan tool and record all freeze-frame data and any related codes to understand the conditions when P0E94 set.
  2. Visually inspect the inverter harness and connector for drive motor B, looking for chafing, corrosion, or loose pins.
  3. Measure the sensor B signal voltage and ground reference at the inverter connector with a digital multimeter and compare to specifications.
  4. Perform a wiggle test on the harness while monitoring the sensor voltage to reveal intermittent wiring faults.
  5. Check the 12-volt battery condition and charging system, as low system voltage can corrupt sensor readings.
  6. If the circuit and sensor check out, follow the manufacturer's diagnostic flow for internal inverter testing or replacement.
  7. After repairs, clear the code and perform a road test to verify the fault does not return under load.

What the voltage sensor B circuit really monitors

  • The voltage sensor B circuit often measures a specific phase voltage or a divided bus voltage, so a fault can be caused by a failing sense resistor rather than a simple wiring break.
  • Technicians sometimes replace the entire inverter when the actual problem is a corroded connector pin that can be repaired with a terminal kit.
  • A low or unstable 12-volt supply can set this code because the inverter's internal reference voltage drifts, so always load-test the auxiliary battery first.
  • This code can be stored intermittently by electrical noise from a failing high-voltage cable or a poor chassis ground, which may not appear during a static test.
  • P0E94 does not always mean the inverter is defective; a shorted sensor signal wire to ground or power can mimic an internal failure.

Can I keep driving with P0E94?

Do not continue driving with this code active, because the vehicle may lose propulsion without warning and high-voltage system faults can be hazardous. Have the vehicle towed to a qualified service facility for diagnosis and repair.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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