P0C1A: Drive Motor B Torque Delivered Performance

What it means

The hybrid control module detects that drive motor B torque output does not match the commanded value. Magnet weakness, phase imbalance, or feedback drift.

At a glance

• Usually lights the check-engine light
• The engine or gearbox may go into limp mode

How it works

Drive Motor B converts electrical power into torque, and the hybrid control module compares the torque it estimates as delivered with the torque it commands. P0C1A sets when that comparison shows Drive Motor B is not meeting the command, which can result from weakened magnet flux, phase-current imbalance, or feedback drift.

Common causes

Most likely first.

1. Magnet flux degraded
2. Phase current imbalance

Symptoms

• EV/hybrid system warning light on
• Reduced motor power or torque
• Possible limp mode or vehicle shutdown

How to diagnose it

1. Record freeze-frame data and compare commanded and estimated Drive Motor B torque in live data to identify the conditions when they diverge.
2. Check for related hybrid-system codes that could explain incorrect motor position, current measurement, or torque estimation.
3. Inspect Drive Motor B’s high-voltage phase connections and relevant sensor wiring for damage, looseness, corrosion, or heat marks, following high-voltage safety procedures.
4. Compare Drive Motor B phase-current readings and position feedback under the manufacturer’s specified test conditions.
5. If wiring and feedback checks pass, have Drive Motor B and its inverter assessed for phase imbalance or reduced magnet flux using the manufacturer’s procedure.

Common fixes

• Repair loose or damaged Drive Motor B phase connections or feedback wiring.
• Resolve related position-sensor or current-sensing faults affecting torque calculation.
• Repair or replace the inverter if it produces an out-of-balance phase current.
• Repair or replace Drive Motor B if weakened magnet flux is confirmed.

Can I keep driving?

Limit acceleration and avoid towing or steep climbs because Drive Motor B may not deliver the requested torque and limp mode can occur. Stop safely if power loss becomes severe or the vehicle reports a shutdown risk.