Forenza 2007

Engine Coolant Temperature Sensor

Print

Operation



Specific to:

Suzuki Forenza 2007-2008

Suzuki Reno 2007-2008

The Engine Coolant Temperature (ECT) sensor is a thermistor (a resistor which changes value based on temperature) mounted in the engine coolant stream. Low coolant temperature produces a high resistance (100,000 ohms at -40°C [-40°F]) while high temperature causes low resistance (70 ohms at 130°C [266°F]).

The Engine Control Module (ECM) supplies 5 Volts to the ECT sensor through a resistor in the ECM and measures the change in voltage. The voltage will be high when the engine is cold, and low when the engine is hot. By measuring the change in voltage, the ECM can determine the coolant temperature. The engine coolant temperature affects most of the systems that the ECM controls. A failure in the ECT sensor circuit should set a diagnostic trouble code P0117 or P0118. Remember, these diagnostic trouble codes indicate a failure in the ECT sensor circuit, so proper use of the chart will lead either to repairing a wiring problem or to replacing the sensor to repair a problem properly.

Removal & Installation



Specific to:

Suzuki Forenza 2007-2008

Suzuki Reno 2007-2008

  1. Relieve the coolant system pressure.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Disconnect the Engine Coolant Temperature (ECT) sensor connector.
  6.  
  7. Remove the ECT sensor from the Electronic Ignition (EI) system ignition coil adapter.

    Click image to see an enlarged view

    Fig. Engine Coolant Temperature (ECT) sensor

  8.  

To install:

  1. Coat the threads of the ECT sensor with sealer.
  2.  
  3. Install the ECT sensor into the EI system ignition coil adapter.
  4.  
  5. Tighten the engine coolant temperature sensor to 15 ft. lbs. (20 Nm).
  6.  
  7. Connect the ECT sensor connector.
  8.  
  9. Fill the coolant system.
  10.  
  11. Connect the negative battery cable.
  12.  

Testing



Specific to:

Suzuki Forenza 2007-2008

Suzuki Reno 2007-2008


NOTE
The On-Board Diagnostic (OBD II) System Check prompts the technician to complete some basic checks and store the Freeze Frame and Failure Records data on the scan tool if applicable. This creates an electronic copy of the data taken when the malfunction occurred. The information is then stored on the scan tool for later reference.

  1. The engine must be allowed to cool fully before the ECT and IAT sensor will read close to the ambient temperature in order to check for a possible skewed sensor.
  2.  
  3. Measure the engine coolant temperature with thermometer to determine the actual value the ECT sensor should be. Take into consideration if the engine has been run and the engine coolant has been warmed without opening the thermostat.
  4.  
  5. Disconnect the ECT sensor electrical connector.
  6.  
  7. Using a Digital Voltmeter (DVM), measure the resistance across the ECT sensor terminals.
  8.  
  9. Check the ECT sensor value to actual coolant temperature using the Temperature vs. Resistance table.
  10.  
  11. The ECT sensor should accurately reflect the actual engine coolant temperature.
  12.  
  13. Replace the sensor if it is out of specification.

    Click image to see an enlarged view

    Fig. Temperature vs. Resistance chart

  14.  

 
label.common.footer.alt.autozoneLogo