Hino P244A Fault Code: Filtering Performance – (Missing Substrate)

Technical description

• ECU constantly calculate and accumulate the amount of soot emission from the engine.
• Based on the values of the differential pressure sensor and the DPR temperature sensor, ECU detects clogging and erosion of the DPR.

Description of malfunction

Abnormal drop in differential pressure in DPR part is detected.

DTC set condition

DTC Detection Condition:

• The engine must not be stopped.
• After automatic regeneration.
• Calculated exhaust gas flow quantity of 205 L/s or higher.
• Exhaust brake is inactive.

Judgment Criteria:

Failure is determined when the value of “differential pressure/exhaust gas flow rate” counted in establishing the judgment criteria is lower than the threshold value.

Reset condition

Immediately after normal operation is restored and DPR-related memory is reset.

Indication, warning or system control regulation when the DTC is set

• MIL: ON
• SVS light: OFF

Pre – Inspection Work

Check that the battery voltage is in the normal range.

After – Inspection Work

• Clear all past DTCs.
• Reset DPR related memory.
• Check that no DTC is stored after test drive.

Possible Causes

• DPR filter: Check for intended filter tampering or damage on the rear end surface.
• Abnormal control of the temperature at regeneration.
• Filter damage due to abnormally-high temperature at regeneration due to excessive soot emission.
• Injector: Characteristic abnormality of injection volume.
• SCV: Faulty control of common rail pressure.
• EGR valve: Faulty control of EGR opening angle.
• Diesel throttle valve: Faulty control of diesel throttle valve opening angle.

Confirmation points for judgment

• Faulty differential pressure sensor.
• Check if differential pressure value is wrongly sensed because of damaged hose or wrong connection.
• Check for misjudgment due to clogging, hole or fault in the differential sensor pipe.

Fault in the air flow meter:

• Check for misjudgment due to abnormal air volume for gas flow quantity calculation.

Exhaust gas temperature sensor:

• Check for misjudgment due to characteristic abnormality of the temperature for gas flow quantity calculation.