To limit the amount of pollutants emitted into the atmosphere, Isuzu industrial vehicles can be fitted with a particulate filter known as DPD.
NOTE: DPD is the name chosen by Isuzu for their particulate filters. They are based on DPF technology without any need for additives.
During normal use of the vehicle, the particulates emitted by the engine are retained by this special filter. When the amount of particulate matter exceeds a certain threshold (preset in the engine control unit), the filter is cleaned through a process called "regeneration", which burns the accumulated particulate.
The condition of the DPD filter is evaluated through the pressure sensors placed in the input and output of the DPD filter.
NOTE: Four sensors are installed on the DPD muffler, two for temperature and two for pressure. The pressure sensors are easily recognizable because they are connected to small metal and/or plastic tubes.
Procedure for checking the exhaust pressure
The efficiency of the pressure sensors (and therefore the status of the DPD filter and engine) can be evaluated through a simple check of the values read in Self-diagnosis.
Please follow these steps:
- Check the correct engine oil level.
- Check the condition of the intake and exhaust systems (check for leaks, obstructions, cracks, unauthorized modification, ... ).
- Check the condition of the installation of the pressure sensors on the DPD filter (tubes bent or broken, inverted, position of the sensor, ... ).
- Connect the diagnostic tool and run a regeneration of the DPD filter (if needed, read the special technical bulletin).
- Wait for the completion of the regeneration.
- From the parameters page check the "Exhaust temperature 1" value.
- Make sure the value is below 100 °c. If higher, increase the engine speed to 1,500 rpm and wait until the temperature reaches 100 °c.
- Accelerate the engine at maximum speed and wait for the "Exhaust temperature 1" value to reach 140 °c.
- With the engine at maximum speed, check the "Exhaust differential pressure" value in the parameters page and compare it to the table below.
WARNING: The makes and distinguishing signs of the vehicle manufacturers included in this document are only provided to inform the reader about the potential suitability of the said TEXA products to be used for the vehicles of the above-mentioned manufacturers. References to makes and models contained in this document are to be considered only as a rough guide.