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Generic P — Powertrain

Traction Motor Inverter Control Circuit Range/Performance

Brand: Generic

Type: P — Powertrain

Views: UK: 16 EN: 26 RU: 19

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Open, short, high resistance, or intermittent connection in inverter power or signal wiring
Corroded or loose high-voltage or low-voltage connectors
Faulty traction motor inverter (power electronics, IGBT/MOSFETs, gate drivers)
Faulty traction motor (winding short, open, phase imbalance, insulation breakdown)
Low or unstable DC-link / traction battery voltage
Faulty current or voltage sensors (phase current sensors, DC-link sensor)

Traction system warning lamp or MIL illuminated
Reduced engine/drive power or vehicle in limp/limited-drive mode
Poor or no acceleration, hesitation, or surging under load
Regenerative braking reduced or disabled
Unusual noise from traction motor (mechanical or electrical)
Stored related HV/traction inverter or motor codes, possible loss of torque command

Read and record all stored codes (inverter, motor, battery, BCM, ABS) and freeze frame data
Visual inspection of inverter and motor connectors, harness routing, chafing, heat damage, and corrosion
Verify inverter coolant level/flow and check for overheating evidence
Check DC-link (battery pack) voltage while attempting drive command (observe safety procedures)
Inspect low-voltage power and ground feeds to inverter control electronics
Check CAN/CAN-FD and other communications between inverter and vehicle control modules

DC-link (battery) voltage: within nominal pack voltage range (vehicle-specific; typically hundreds of volts on EV/HEV systems)
Inverter PWM switching: present at inverter outputs during commanded drive; frequency typically in kHz range (verify with scope)
Phase-to-phase AC output voltage: varies with commanded torque; should be proportional to DC-link and not show open phase
Phase currents: follow commanded torque and be balanced between phases; no phase should be zero when torque commanded
Motor speed/position feedback: matches commanded rpm and vehicle speed within tolerance
Inverter temperature: within operating limits; overtemperature faults possible

Retrieve and document all fault codes and freeze-frame data. Check for related codes (battery, contactor, current sensors, CAN).
Perform a full visual inspection of HV and LV harnesses between inverter and motor: look for damage, water ingress, corrosion, or loose pins.
Verify low-voltage power and ground to the inverter control electronics (battery 12V feed, ignition-switched power, ground points).
With appropriate PPE and HV-safe tools, measure DC-link voltage at the inverter input. Confirm within expected pack voltage and stable during commanded torque.
Using a high-voltage-rated oscilloscope or manufacturer test tool, observe inverter output waveforms (phase voltages and PWM). Look for missing phase, distorted waveform, or lack of switching.
Measure phase currents with appropriate sensors; compare to commanded values and check for imbalance or open phase.
Check the motor: perform insulation resistance test, measure DC resistance of phase windings, and check for mechanical binding.
Inspect and test current/voltage sensors and their harnesses; replace or repair if out of spec.
Verify inverter cooling system and temperature sensors; correct coolant flow or overheating issues.
If wiring and sensors pass, consider inverter replacement or reflash/update of inverter control software per manufacturer procedures.
Clear codes and perform a controlled road or dynamometer test to confirm repair and that fault does not return.