What it means
The control module detected an intermittent or erratic signal 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 provides the hybrid or EV control module with a temperature signal. This code sets when that signal jumps, drops out, or varies erratically instead of changing smoothly, often when a loose connection or unstable reference is disturbed.
Common causes
Most likely first.
- Sensor connector not seated
- Noisy ground reference
- Connector with intermittent contact under vibration
Symptoms
- EV/hybrid system warning light on
- Reduced motor power or torque
- Possible limp mode or vehicle shutdown
How to diagnose it
- Review freeze-frame data and live temperature readings for sudden jumps or dropouts, and note when the fault was recorded.
- Inspect the drive motor A sensor plug for incomplete seating, backed-out pins, corrosion, or harness strain near the connector.
- With the vehicle handled according to its service procedure, monitor live data while gently checking the accessible harness for a repeatable signal disturbance.
- Check the sensor ground reference and connector contacts for unstable or noisy connections using the manufacturer's diagnostic procedure.
- If the harness and ground are sound, test the sensor and module input for intermittent operation under the conditions that reproduce the fault.
Common fixes
- Fully seat and secure the sensor connector.
- Repair loose, corroded, or damaged connector terminals.
- Repair chafed wiring or harness strain that interrupts the signal under vibration.
- Restore a stable ground reference where testing identifies a fault.
- Replace the sensor if it produces erratic readings during the manufacturer's test.
Can I keep driving?
Drive gently only if the vehicle is operating normally and no temperature warning is present; intermittent readings can trigger reduced power or a shutdown without much notice. Stop safely if the warning escalates or propulsion becomes unreliable.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.