P0A67: Drive Motor B Phase U Current Low

What it means

Drive motor B phase U 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 U winding to produce torque. The module compares measured phase U current with the expected value and sets this code when the current is too low, potentially because the winding is partly open or the current sensor has drifted.

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 U current with phases V and W under similar operating conditions.
2. With the vehicle safely powered down according to the manufacturer’s procedure, inspect the motor B phase U wiring and connectors for loose connections, corrosion, heat damage, or chafing.
3. Check for related motor B, inverter, and current-sensor codes that could identify a shared electrical issue.
4. Have the motor B phase U 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 U current sensor and signal circuit for offset or measurement error.

Common fixes

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

Can I keep driving?

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