Sensor, Coolant Temperature: Operation: Operation
WARNING: This page is about a different car, the 2012 RAM Pickup and 2012 RAM Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
At key-on, the Powertrain Control Module (PCM) sends out a regulated 5 volt signal to the ECT sensor. The PCM then monitors the signal as it passes through the ECT sensor to the sensor ground (sensor return).
When the engine is cold, the PCM will operate in Open Loop cycle. It will demand slightly richer air-fuel mixtures and higher idle speeds. This is done until normal operating temperatures are reached.
The PCM uses inputs from the ECT sensor for the following calculations:
- for engine coolant temperature gauge operation through CAN Bus communications
- Injector pulse-width
- Spark-advance curves
- ASD relay shut-down times
- Idle Air Control (IAC) motor key-on steps
- Pulse-width prime-shot during cranking
- O2 sensor closed loop times
- Purge solenoid on/off times
- Cooling fan control
- Temperature gauge operation
- A/C cutoff at high coolant temperatures
- EGR solenoid on/off times (if equipped)
- Evaporation System Integrity Monitor (ESIM) operation (if equipped)
- Radiator fan relay on/off times (if equipped)
- Target idle speed