Chrysler
Type:
    Powertrain - Fuel and Air Metering - ISO/SAE Controlled
Description:
    ECT Sensor Circuit Low Input Conditions
Cause:
    Key on and then the PCM detected an ECT sensor input of less than 0.51v for over three seconds.

Ford
Type:
    Powertrain - Fuel and Air Metering - ISO/SAE Controlled
Description:
    ECT Sensor Low Conditions
Cause:
    Key on or engine running, then the PCM detected an ECT sensor signal of less than 0.20v (250°F)

Generic
Type:
    Powertrain - Fuel and Air Metering - ISO/SAE Controlled
Description:
    Engine Coolant Temperature Sensor 1 Circuit Low

GM
Type:
    Powertrain - Fuel and Air Metering - ISO/SAE Controlled
Description:
    ECT Sensor Circuit Low Input Conditions
Cause:
    Key on or engine running, then the PCM detected that the ECT sensor input was more than 246°F, condition met for 500 ms.

Nissan
Type:
    Powertrain - Fuel and Air Metering - ISO/SAE Controlled
Description:
    Engine coolant temperature (ECT) sensor - voltage low
Cause:
    Wiring, ECT sensor, ECM