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DTC codes / P0Exx · Hybrid propulsion / P0E90

P0E90Drive Motor A Inverter Voltage Sensor B Circuit Range/Performance

P0E90 indicates that the inverter for drive motor A has detected an abnormal voltage reading from its 'B' voltage sensor circuit, which is used to monitor the high-voltage bus or phase voltage. The computer sets this code when the sensor signal falls outside the expected range or does not correlate properly with other voltage measurements, often indicating a faulty sensor, wiring issue, or inverter internal problem.

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

Symptoms you may notice

  • Illumination of the check engine light or service vehicle soon message
  • Reduced power or limp mode, as the inverter may limit motor output to protect the system
  • The vehicle may refuse to start or enter 'ready' mode if the fault is severe
  • Inconsistent or erratic power delivery during acceleration
  • Often no symptoms besides the warning light, especially if the fault is intermittent

Common causes, most likely first

  1. Faulty voltage sensor B inside the inverter assembly
  2. Damaged or corroded wiring or connector at the inverter voltage sensor circuit
  3. High-voltage cable or busbar connection issue causing voltage signal anomalies
  4. Internal inverter fault, such as a failed sensing circuit or control board
  5. Software or calibration error in the inverter control module
  6. Moisture intrusion or contamination in the inverter housing affecting sensor operation

How to diagnose and fix it

  1. Use a scan tool to retrieve all stored codes and freeze-frame data, and check for related codes in other modules
  2. Visually inspect the inverter wiring harness and connectors for damage, corrosion, or loose pins
  3. Perform a voltage drop test on the sensor circuit and compare readings with manufacturer specifications
  4. Check for technical service bulletins (TSBs) or software updates for the inverter control module
  5. If the sensor is serviceable separately, replace it; otherwise, replace the inverter assembly as needed
  6. Clear codes and perform a road test to verify the repair, monitoring live data for the voltage sensor signal

Voltage Sensor B Circuit Pitfalls

  • A common misdiagnosis is replacing the entire inverter when the fault is simply a chafed wire in the sensor circuit, so always perform a thorough wiring inspection first.
  • Intermittent codes can be caused by loose connector terminals that only act up under vibration or temperature changes, so wiggle tests and load tests are essential.
  • The code may set due to a low 12-volt battery or charging system issue affecting the inverter's reference voltage, so check the auxiliary battery condition before condemning high-voltage components.
  • Some vehicles require a specific relearn or calibration procedure after sensor replacement, and skipping it can cause the code to return immediately.
  • Related codes in the battery energy control module or motor control module can indicate a communication or high-voltage interlock issue that mimics a sensor fault.

Can I keep driving with P0E90?

If the vehicle enters limp mode or refuses to start, do not continue driving; have it towed to a qualified technician. If the car drives normally with only the warning light on, limit driving to a short distance to a repair shop and avoid heavy acceleration or high-speed driving.

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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