P0CBF: Drive Motor A Coolant Temperature Sensor Circuit High

What it means

The control module detected a high signal condition in the drive motor A coolant temperature sensor circuit. The cause and vehicle response depend on the vehicle.

At a glance

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

How it works

The drive motor A coolant temperature sensor sends a temperature signal to the hybrid or EV control module. This code sets when the signal is higher than the circuit's expected range, which can result from an open circuit or a signal pulled toward battery voltage.

Common causes

Most likely first.

1. Signal wire shorted to B+
2. Open sensor
3. Connector pins corroded - high contact resistance

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 and live data for drive motor A coolant temperature; check whether the reported value is implausibly high or fixed at an extreme.
2. Inspect the sensor connector and harness for a disconnected plug, corrosion, damaged insulation, or a signal wire contacting battery voltage.
3. Check connector seating and pin tension, then verify sensor power, ground, and signal paths using the manufacturer's wiring information.
4. Test the signal circuit for an open and for a short to B+, and compare continuity and circuit behavior with the manufacturer's specification.
5. If the wiring checks out, test the temperature sensor and module input according to the manufacturer's procedure.

Common fixes

• Reconnect a loose sensor plug or repair a damaged connector.
• Repair a signal wire shorted to B+ or an open in the sensor circuit.
• Clean or replace corroded terminals that prevent proper contact.
• Replace the sensor if it is open or fails the manufacturer's test.
• Repair a module-side circuit fault if testing identifies one.

Can I keep driving?

Limit driving and avoid heavy loads if motor power is reduced, since the control module may not be able to judge motor temperature correctly. Stop if a temperature warning appears, the vehicle enters limp mode, or propulsion becomes unreliable.