P2C6B

Code

Generic P — Powertrain

Drive Motor “A” Phase X Current High

Brand: Generic

Type: P — Powertrain

Views: UK: 24 EN: 47 RU: 28

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Page language: EN

Causes

Shorted or damaged phase conductor between inverter and motor (phase X)
Faulty motor phase current sensor (shunt, Hall-effect sensor, or CT)
Inverter (motor controller) power electronics failure on phase X output
Open or high-resistance connector, damaged wiring harness or pin corrosion
Motor winding short, internal coil damage, or thermal degradation
DC bus overvoltage combined with control fault causing excessive phase current

Symptoms

Malfunction Indicator Lamp / EV system warning light illuminated
Reduced drive power, limited propulsion or limp-home mode
Drive motor fault codes stored (phase overcurrent)
Unusual motor noise, vibration, or heating of motor/inverter
Possible loss of regeneration or altered vehicle drivability
Intermittent faults that may clear after restart if caused by connectors or temperature

What to check

Read stored DTC(s) and freeze-frame/fault data with a capable scan tool; note drive conditions (speed, torque, DC bus voltage, temperature).
Inspect high-voltage harness, connectors, and shielding for damage, burns, or water ingress—especially phase X conductor.
Verify HV interlocks, fuses, and contactors are intact and operating correctly.
Check inverter/motor cooler integrity and verify motor/inverter temperatures are within range.
Visually inspect motor for signs of overheating, burning, or ingress.
Measure DC bus (inverter supply) voltage while performing controlled tests (follow safety procedures).

Signal parameters

Standstill (motor not commanded): phase currents ≈ 0 A (minor stray currents negligible).
Normal acceleration: phase currents vary with torque demand; peak RMS values depend on vehicle but typically range from tens to several hundred amperes in high-power systems.
Phase-to-phase balance: phase currents should be within a small percentage (commonly ±5–15%) of each other when producing equal torque.
Overcurrent fault trigger: vehicle-specific — commonly an instantaneous exceedance above the rated phase current or sustained current above threshold (examples: >200–600 A peak in many systems).
Waveform: three-phase sinusoidal or PWM-modulated current with ~120° phase displacement; abnormal distortion, DC offset, or a single-phase spike indicates fault.
Sampling: use HV-rated current probes and an oscilloscope or manufacturer diagnostic tool capable of capturing high-frequency PWM and RMS values.

Diagnostic algorithm

Safety first: follow manufacturer HV safety procedures, isolate high-voltage system, use PPE, and disable service plug or traction battery per procedure before any physical inspection.
Retrieve DTC P2C6B and related codes with a qualified scan tool. Record freeze-frame data (vehicle speed, torque request, DC bus voltage, temperatures).
Visually inspect phase X wiring, connectors, and pin condition at inverter and motor; repair any physical damage or corrosion.
With HV system enabled and proper safety measures, measure DC bus voltage to confirm proper supply during a controlled test.
Using HV-compatible current clamps/oscilloscope or manufacturer diagnostic tool, monitor all three phase currents and compare waveforms and RMS values under controlled torque demand (low-speed, low-load test first).
If phase X current is high while others are normal, suspect wiring/connector or inverter output leg; if all phases are abnormal, suspect controller/software or DC bus issue.
Check continuity and insulation resistance (megger) of the phase X conductor and motor winding (with system isolated) to detect shorts to ground or between phases.
Test or swap the phase current sensor (if possible) or verify its supply and signal integrity to the inverter/ECU; inspect sensor wiring for shorts or opens.
Run inverter self-tests/diagnostics and check for internal inverter faults or power stage errors. Follow manufacturer-guided actuator/motor tests if available.
If inverter output is confirmed faulty (isolated to one leg) consider inverter rebuild/replace. If motor winding fault is confirmed, repair or replace motor as required.
After repairs, clear codes, perform controlled functional tests and a test drive while monitoring phase currents and temperatures. Ensure no recurring faults before returning vehicle to service.

Likely causes

Damaged wiring/connector or pin corrosion on phase X between inverter and motor
Faulty phase current sensor or its wiring (incorrect reading)
Inverter output stage fault on the phase X leg
Internal motor winding short or insulation failure

Fault status

⚠️ Status

Drive Motor A — Phase X current is higher than allowed. The drive motor/inverter detected an overcurrent or abnormal current on phase X. Check wiring, current sensors, inverter output stage and motor windings.

🔴 Repair difficulty: Hard

⏱️ Diagnostic time: 2.0-5.0 hours