P0C13: Drive Motor A Inverter Phase W Over Temperature

What it means

The inverter phase W of drive motor A reports junction temperature above the protection threshold. Sustained high phase current.

At a glance

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

How it works

Drive motor A's inverter phase W switches current through the motor's W phase path. The control module monitors the phase W junction temperature and sets this code when it exceeds the protection limit, often after sustained phase overload or loss of local cooling.

Common causes

Most likely first.

1. Sustained phase overload
2. Local cooling failure

Symptoms

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

How to diagnose it

1. Read freeze-frame data and related codes to see the phase W temperature, motor load and operating conditions when the fault set.
2. Check live inverter temperature and phase data, if available, to see whether phase W remains hotter than phases U and V.
3. With the vehicle powered down as directed by the manufacturer, inspect the inverter cooling system for leaks, blocked flow or damaged connections.
4. Check for conditions that could overload phase W, including related motor phase or wiring faults recorded by the control module.
5. Test the inverter cooling and phase W circuit using the manufacturer's diagnostic procedure to distinguish a cooling fault from an electrical overload.

Common fixes

• Restore coolant flow by correcting a blockage or leak in the inverter cooling circuit.
• Repair damaged phase W wiring or connections if tests identify a fault.
• Correct the confirmed motor or load condition causing sustained phase W overload.
• Repair or replace the inverter if testing confirms an internal phase W thermal fault.

Can I keep driving?

Avoid heavy acceleration, towing or sustained high load, and stop if the vehicle limits power or warns of overheating. Continued operation can trigger limp mode or shutdown.