Coolant temperature sensor, engine management system
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Coolant temperature sensor, engine management system
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The task of the temperature sensor is to inform the engine control module of the current engine coolant temperature.
The temperature sensor has the following connections
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1.
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Signal, water temperature: Pin 1 on the temperature sensor is connected to pin 89 on the engine control module
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2.
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Sensor ground: Pin 2 on the temperature sensor is connected to pin 93 on the engine control module
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The engine coolant temperature sensor is located on top of the thermostat housing on the front right-hand side of the engine bay. It is an NTC type sensor and is power by 5V from the engine control module.
The resistance of the temperature sensor changes with the temperature. The sensor resistance takes the following values:
20°C (68°F)
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2500 Ohm 6%
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100°C (212°F)
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186 Ohm 6%
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If the sensor input is short-circuited to B+, diagnostic trouble code P0115 will be generated.
If the sensor input is short-circuited to ground, diagnostic trouble code P0116 will be generated.
When the engine speed exceeds 2000 rpm for the first time having been started, the control module orders the temperature of the coolant to be checked. The temperature should have risen above 0° after 3 minutes. If this condition is not met, DTC P0117 will be generated.
System reaction to a fault
P0115 and P0116
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As soon as the control module detects the fault, the system uses the fuel temperature. -25°C is used for glow duration control and +50°C for calculating injection start.
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The diagnostic tool reading is -50° when P0115 has been generated.
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The diagnostic tool reading is +200° when P0116 has been generated.
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P0117
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As soon as the control module detects the fault the substitute value 0°C is used.
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The diagnostic tool reading is the same as the fuel temperature when P0117 has been generated.
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