When the Service Tool is turned on, its serial number and software version is displayed. 
The Service Tool's switch has three positions, "CHECK SENSOR" to the left, "OFF" in the middle and "TEST ALARM" to the right.  
The selected function will be indicated on the screen:
CHECK SENSOR:  In this mode, the sensor is heated up to 75ºC and kept there.  This adjustment is used to check if the OHS and the Service Tool are measuring the temperature alike.
OFF:  At this adjustment, the sensor does not heat up, while the temperature is measured and displayed.
TEST ALARM:  In this mode, the sensor is heated further up to 100ºC, so that it goes higher than the Alarm temperature.  In doing so, it can be tested whether the OHS's alarm function is working correctly.

Service Tool Sensor Faulty:  If the Service Tool's sensor is faulty, an on-screen message will alert the user and the Service Tool will do nothing further.

  

Service (check and test) of the OHS:
It is recommended that the OHS be serviced (checked and tested) every six months.
      
Steps to be followed:    
Mechanical checking:  Check that all couplings, the sensor, and the box are firmly fixed and no cables/wires are damaged.      
If there is a fault with the sensor or if one of its wires are loose, the OHS will immediately warn that the sensor is faulty.  The Engine will not be turned off, but the error message will be displayed continuously until the error is fixed. 

Check the Temperature Sensor: The OHS's sensor is checked by detaching the sensor from the engine and screwing it onto the Service Tool's sensor, allowing the Service Tool to heat it up.  The Service Tool is set to "CHECK SENSOR" .  It is normal that, while the sensor is heating up, the temperature displayed by the Service Tool will be about 8ºC higher than that on the OHS.  The Service Tool's temperature will stabilise between 75 and 78ºC.  If the OHS measures correctly, its temperature should be about 2 degrees below the Service Tool's temperature.  If the difference is more than 6ºC, it should be re-calibrated and/or the sensor should be replaced. 

 

Check the Normal Engine Temperature vs. the Alarm Temperature:
The engine temperature shown on the OHS, while the engine is at normal temperature, should then be compared to the Alarm temperature.  
If the Engine temperature is more than 15ºC lower than the Alarm temperature, this may indicate a calibration error. In this case there should be ensured that the engine is actually at its normal operating temperature and if so, the calibration should be redone. If the Engine temperature is less than 5ºC lower than the Alarm temperature, this may also indicate a calibration error.  In this case, again, there should be ensured that the engine is actually at its normal running temperature and if so, the calibration should be redone.

 

Test the Alarm function: 
The Alarm function is tested by setting the Calibration Tool to "Test".  
The Calibration Tool will then heat the OHS's sensor to a temperature above the Alarm temperature.  Once the OHS's engine temperature reaches its Alarm Temp, the OHS should trigger the alarm. 

 

If the OHS's alarm does not trigger, then there is an error and the OHS should be replaced.

 

Check the Oil Pressure Sensor

Check the Oil Pressure Alarm function:  

If the vehicle is switched on but the engine is not started up, there will be no oil pressure and therefore the oil pressure warning LED Orange should light up within about 5 seconds. After that, with about 3 minutes intervals, the Red LED will flicker. If the oil pressure LED is not triggered in this situation, then the OHS's oil pressure function is faulty.

Check if the OHS's Oil Pressure function works if oil pressure is OK:  

The test is done by removing the green oil pressure wire from the oil sensor and connect it to ground on the engine.  The Orange Oil Pressure LED should immediately go off, indicating that the oil pressure is OK.  Note that this test does not mean that the oil pressure sensor is OK or that the engine generates sufficient oil pressure. 
Check that the engine's oil pressure sensor works OK and that the engine generates sufficient oil pressure:  As soon as the engine is started and sufficient oil pressure is generated by the engine, the oil pressure LED should go off.  If the oil sensor alarm is triggered while the engine is running, then it means that the oil pressure is too low or that the oil pressure sensor is faulty. 

 

Service Tool / Testing unit R2300 excl vat

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