| Low Coolant Temperature | |
| Parameter | Default Setting |
| Warning setpoint | 80 °C (176 °F) |
| Warning delay | 5 seconds |
| Activation delay | 10 minutes |
| Hysteresis | 5 °C (9 °F) |
| Security level | No required password |
To activate this strategy, the engine must operate for a minimum of ten minutes and the coolant temperature must be below 80 °C (176 °F) for five seconds. A warning will then occur. To deactivate the warning, the following condition must occur:
- The coolant temperature must rise above 85 °C (185 °F).
The setpoint can be programmed in the range of 63 to 85 °C (145 to 185 °F).
Note: The low coolant temperature is monitored in order to detect a failure of the water temperature regulators. This feature is not intended to monitor the operation of jacket water heaters.
Coolant Temperature Input Circuit
The temperature of the engine coolant is measured by an electronic sensor. The sensor is mounted on the cover of the regulator housing. The signal from the sensor is used to modify the fueling of the engine. The signal is also used to modify the timing for an improved cold start and reduction in white smoke. The ECM supplies the coolant temperature sensor with 5.0 ± 0.5 VDC. The sensor's output voltage is 0.4 to 4.6 VDC. This depends on the temperature of the engine's coolant.