P0A6D: Drive Motor B Phase W Current Low

What it means

Drive motor B phase W current is below the expected range. The code identifies a low-current condition but does not establish its cause.

At a glance

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

How it works

The inverter controls current through drive motor B’s phase W winding to make torque. The module compares measured phase W current with the expected value and sets this code when the current is too low; a partly open winding or a drifted current-sensor offset can cause that reading.

Common causes

Most likely first.

1. Phase winding partially open
2. Current sensor offset drifted

Symptoms

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

How to diagnose it

1. Save freeze-frame data and compare live motor B phase W current with phases U and V under similar operating conditions.
2. With the vehicle safely powered down according to the manufacturer’s procedure, inspect motor B phase W wiring and connectors for loose connections, corrosion, heat damage, or chafing.
3. Check for related motor B, inverter, and current-sensor codes that could point to a shared electrical problem.
4. Have the motor B phase W winding and connections checked for an open or excessive resistance against the manufacturer’s specification.
5. If the winding and wiring pass, test the phase W current sensor and signal circuit for offset or measurement error.

Common fixes

• Repair a loose, damaged, or corroded phase W connector or wire.
• Repair an open or damaged motor B phase W winding if confirmed.
• Correct the phase W current-sensor circuit or replace the sensor if testing confirms it has drifted.
• Repair or replace the inverter only if testing confirms it is responsible for the low reading.

Can I keep driving?

Avoid driving if torque is reduced or limp mode activates, and stop safely if a shutdown warning appears because propulsion may be limited or lost. Continued operation with a winding or measurement fault may worsen damage.