Engine Coolant Temperature Sensor 1

The engine computer is getting weird info from the coolant temp sensor, which can mess with how the engine runs and its efficiency.

The ECM expects the coolant temperature to be within a certain range, typically between 190°F and 220°F when the engine is at normal operating temperature. If it sees a value that is too low (below 160°F) or too high (above 240°F) without a corresponding actual condition, it triggers this code.

Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.

1. 1Check coolant level; ensure it's at the correct level and not leaking.
2. 2Inspect the wiring and connectors to the coolant temperature sensor for damage or corrosion.
3. 3Using a scan tool, monitor the coolant temperature reading when the engine is running. It should correlate with the actual temperature you measure at the engine.
4. 4If reading is out of expected range, swap the temperature sensor with a known good one and check for code return.
5. 5If the code returns, check ECM for updates or faults.

• Faulty coolant temperature sensor
• Corroded or damaged wiring
• Poor connection at the sensor
• Coolant leaks affecting temperature readings
• Faulty engine control module (ECM)

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