Enhance TD5 Defender Performance with Engine Coolant Temperature Sensor
ENGINE MANAGEMENT SYSTEM
11
DESCRIPTION AND OPERATION
SENSOR - ENGINE COOLANT TEMPERATURE
(ECT)
The ECT sensor is located in the coolant outlet elbow on top of the engine. It provides the ECM with engine
coolant temperature information. The ECM uses this information for the following functions:
•
Fuelling calculations.
•
Temperature gauge.
•
To limit engine operation if coolant temperature is to high.
•
Cooling fan operation.
•
Glow plug operating time.
The ECT works as an NTC sensor. As temperature rises, the resistance in the sensor decreases, as temperature
decreases, the resistance in the sensor increases. The ECM compares the voltage signal to stored values and
compensates fuel delivery to ensure optimum driveability at all times.
Inputs / Outputs
The ECT sensor (C0169-2) is provided a feed by the ECM (C0158-7) on a pink/green wire. The sensor is provided
an earth path (C0169-1) via the ECM (C0158-18) on a pink/black wire.
The ECT can fail or supply an incorrect signal if one or more of the following occurs:
•
Sensor open circuit.
•
Short circuit to vehicle supply.
•
Short circuit to vehicle earth.
•
Incorrect mechanical fitting.
•
Signal fixed above 40
°
C (104
°
F) not detected.
•
Signal fixed below 40
°
C (104
°
F) not detected.
In the event of an ECT sensor failure, any of the following symptoms may be observed:
•
Difficult cold start.
•
Difficult hot start.
•
Driveability concerns.
•
Instrument pack warning lamp illuminated.
•
Temperature gauge reads excessively hot.
•
Temperature gauge reads excessively cold.
In the event of a component failure the ECM calculates coolant temperature from the fuel temperature signal. If
this occurs, the limit of engine operation if coolant temperature becomes too high becomes inoperative.