P2C6C

Code

Generic P — Powertrain

Drive Motor “A” Phase Y Current

Brand: Generic

Type: P — Powertrain

Views: UK: 29 EN: 39 RU: 30

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Page language: EN

Causes

Open or short circuit in Phase Y motor conductor between inverter and motor
Damaged or corroded high-voltage connector or terminal for Phase Y
Faulty current sensing circuit inside the inverter / drive controller
Internal motor winding damage or short in Phase Y
Poor inverter ground or supply voltage irregularity
Water intrusion or insulation breakdown in the motor or harness

Symptoms

Reduced drive power or motor derate
Drive system warning light / EV system lamp illuminated
Intermittent or persistent limp-home mode
Unusual motor noise or vibration under load
Loss of regeneration / traction control warnings

What to check

Retrieve all related codes and freeze-frame data with a capable scan tool (record operating conditions)
Visually inspect high-voltage phase cables, connectors, and harness around motor and inverter for damage, corrosion, or water ingress
Confirm vehicle high-voltage interlock is safe and remove service plugs / isolate battery before any hands-on HV testing
Check for other inverter/motor codes that may narrow fault (phase X/Z, DC link faults, ground faults)
Verify vehicle voltage and DC bus health at the inverter (no undervoltage/overvoltage events)

Signal parameters

Phase Y current amplitude: should be similar to Phase X/Z under comparable load (values vary by vehicle and load)
Waveform: 3-phase AC sine or PWM-derived waveform on all three phases; Phase Y should not be flat or missing pulses
DC bus voltage: stable within specification during test (refer to manufacturer values)
Imbalance: phase-to-phase current imbalance should be minimal under steady load
Frequency: motor electrical frequency proportional to motor speed; Phase Y should match other phases

Diagnostic algorithm

Safety first: follow high-voltage safety procedures. Disable HV system, remove service disconnect and verify with proper HV meter before touching wiring.
Use a scan tool: read freeze frame and live data. Note phase currents, DC bus voltage, and related inverter/motor codes.
Visual inspection: examine Phase Y conductor, connectors and motor for damage, heat discoloration or moisture. Repair any obvious damage.
Wiggle test: with vehicle safe and powered down, flex connectors and wiring to check for intermittent faults. Re-check codes after any movement tests.
Measure insulation/resistance: with HV isolated, measure resistance between phase conductors and to ground per manufacturer procedure to detect shorted winding or insulation breakdown.
Power-on current check: using an approved clamp meter or oscilloscope on phase conductors (only if trained and following HV procedure), compare Phase Y current and waveform to the other two phases while running under similar load.
Swap/compare: if possible and safe, compare measurements to a known-good motor or inverter, or swap connectors between phases only if manufacturer allows to isolate motor vs inverter fault.
Inverter diagnostics: if phase wiring and motor check OK, suspect inverter internal current sensor or driver failure. Follow manufacturer inverter test procedures or send inverter for bench testing/repair.
Repair and retest: repair wiring/connectors or replace failed components. Clear codes and perform road test under the same conditions recorded in freeze-frame to confirm repair.
If uncertain, consult manufacturer-specific procedures and consider high-voltage service center or replacement of inverter/motor assemblies.

Likely causes

Loose/corroded Phase Y connector at motor or inverter
Intermittent open/short in phase conductor caused by chafing or damaged insulation
Failed current sensor or measurement electronics in the inverter
Motor internal winding fault (shorted turns) affecting Phase Y current
Inverter power transistor or phase driver failure on Phase Y output

Fault status

⚠️ Status

Drive Motor A Phase Y current abnormal — inverter detected open/short or out-of-range current on Phase Y. Motor may be derated; inspect phase wiring, connectors, inverter and motor windings.

🔴 Repair difficulty: Hard

⏱️ Diagnostic time: 2.0 - 4.0 hours