Engine Coolant Temperature Sensor 2

Your truck's computer has two sensors measuring the engine's coolant temperature. This code means there's a problem with the second sensor, which affects how the engine manages cooling.

The engine control module (ECM) monitors the voltage from the coolant temperature sensor. A properly functioning sensor should output a voltage between 0.5V at -40°C to 4.5V at 150°C. If the ECM detects a voltage outside of expected range or a loss of signal, 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. 11. Check the coolant level in the reservoir and radiator; refill if low before proceeding. Decision Point: is the coolant level adequate? Yes: go to step 2; No: fix coolant level and retest.
2. 22. Inspect the wiring and connector for the coolant temperature sensor 2. Look for frayed wires, corrosion, or loose connections. Decision Point: are the wiring and connector in good shape? Yes: go to step 3; No: repair/replace wiring and retest.
3. 33. Using a multimeter, measure the voltage at the sensor harness while the engine is running. The reading should be within normal expected values. Decision Point: is the voltage normal? Yes: go to step 4; No: replace the coolant temperature sensor.
4. 44. If the sensor is new, check for ECM updates or resets. If everything is up-to-date and voltage readings are normal, the ECM may be at fault. Decision Point: replace ECM? Yes: replace it; No: further diagnostics needed.

• Corroded or damaged wiring to the sensor
• Faulty coolant temperature sensor
• Poor connection at the sensor
• ECM software failure
• Incorrect coolant level affecting sensor operation

$$