What it means
The ECM detects a circuit fault on the hybrid/ev electronics coolant temperature sensor a circuit. Reading cannot be used reliably for control.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Electronics coolant temperature sensor A measures coolant temperature in the hybrid or EV power electronics cooling system, and the ECM uses its signal to assess cooling conditions. P0CEE sets when the sensor A circuit has an electrical fault that makes the temperature reading unreliable.
Common causes
Most likely first.
- Sensor failed
- Wiring or connector fault
Symptoms
- Hybrid or EV system warning light on
- Reduced power or limited vehicle operation
- Cooling-system warning may appear
How to diagnose it
- Read freeze-frame data and compare sensor A's scan-tool temperature with other available temperature readings and ambient conditions.
- With the vehicle powered down according to the manufacturer's high-voltage safety procedure, inspect sensor A's connector for corrosion, moisture, loose pins, or damage.
- Inspect the sensor A wiring for breaks, chafing, or a poor ground or supply connection.
- Test sensor A's circuit and sensor response against the manufacturer's wiring diagram and specifications.
- If the circuit and sensor test correctly, check the control module connection and related circuit path using the manufacturer's procedure.
Common fixes
- Clean and secure corroded or loose sensor A connector terminals.
- Repair damaged sensor A wiring or a poor circuit connection.
- Replace electronics coolant temperature sensor A if it fails testing.
- Repair a control-side circuit fault confirmed by testing.
Can I keep driving?
Drive only as needed if no cooling warning or power reduction is present, and avoid heavy loads because the system may not have a reliable electronics coolant temperature reading. Stop safely if a cooling warning or limited-power condition appears.
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.