EGR Temperature Sensor

EGR Temperature Sensor Circuit:

functions to convert the data regarding the temperature of the EGR gas downstream from the EGR valve to Voltage, and to input that Voltage (as signals) to the engine control module.

The 5V power supply within the engine control module is supplied, by way of the resistance within the unit, to the EGR temperature sensor; it passes through the EGR temperature sensor, which is a type of resistor, and is grounded at the engine control module. Note that the resistance of the EGR temperature sensor decreases when the EGR gas volume increases and the temperature of the EGR gas increases.

The EGR temperature sensor terminal Voltage becomes higher when the resistance of the EGR temperature sensor increases, and becomes lower when the resistance decreases. Consequently, the EGR temperature sensor terminal Voltage varies in accordance with the temperature of the EGR gas becoming lower when the temperature of the EGR gas increases.

To test the EGR Temperature Sensor, located on the EGR valve, proceed as follows.

EGR Temperature Sensor Test:

COMPONENT TEST
1. Place the EGR temperature Sensor in water and heat to 50°C (122°F).
2. Read the resistance value between terminals 1 and 2, resistance should be between 60 - 83 K Ohms.
3. Heat the water to boiling, 100°C (212°F).
4. Read the resistance value between terminals 1 and 2, resistance should be between 11 - 14 K Ohms.

If the EGR Temperature Sensor measures out of the specification range, replace the sensor.


HARNESS TEST:
1. Disconnect the EGR temperature sensor connector and turn the key to the ON position.
2. Using a Voltmeter, measure the power supply Voltage between the harness connector terminal 2 and ground.

Voltage:
4.3 - 4.7 Volts.

3. Check for continuity between the EGR temperature sensor harness connector terminal 1 and ground.

Continuity:
Should exist



If any of the previous tests produce unsatisfactory results, the harness will need to be repaired or replaced. Once repairs have been completed, clear the trouble codes and road test the vehicle to confirm that the repair has corrected the problem and the code doesn't return.
If the trouble code returns, it is possible that there is an intermittent failure of the component or the ECU. Check for looseness at all harness junctions and test for an intermittent failure.