P244A – DPF Differential Pressure Too Low Euro5b MMC L200 IV



FUNCTION

  • The engine-ECU monitors the difference between exhaust gas pressures at the inlet and outlet of the DPF by using the exhaust differential pressure sensor.
  • If the difference is abnormally low, the engine-ECU will determine that the DPF is melted down or missing.

  • TROUBLE JUDGMENT

  • Battery positive voltage is 8 – 16 V.
  • 2 seconds later after the ignition switch has been in “ON” position or the engine has started up.
  • The No. 2 exhaust gas temperature sensor temperature (catalyst temperature) exceeds the specified value.
  • The No. 3 exhaust gas temperature sensor temperature (DPF temperature) exceeds the specified value.
  • Exhaust flow rate exceeds the specified value.
  • Engine speed is within the predetermined range.
  • Final fuel injection quantity exceeds the specified value.
  • DPF differential pressure is below the specified value.

  • FAIL-SAFE AND BACKUP FUNCTION

  • The DPF regeneration is prohibited.

  • PROBABLE CAUSE

  • The exhaust pressure hose or the exhaust pressure pipe is disconnected or damaged.
  • The DPF melted down.
  • The DPF missing.

  • DIAGNOSIS PROCEDURE

    STEP 1. Check exhaust pressure hose and exhaust pressure pipe.

  • Check the lines between the exhaust differential pressure sensor and the DPF (i.e, exhaust pressure hose and exhaust pressure pipe) for disconnection or damage.
  • Q. Are the check results normal?

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