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Hino P2459 Fault Code: FREQUENT REGENERATION

17/10/2025

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Technical Description

ECU constantly calculate and accumulate the amount of soot deposit from the engine.
Moreover, based on the accumulated amount, the regeneration interval is determined.

Failure is detected for DPR prescribed regeneration interval.

There was a difference between the actual amount of soot deposit calculation and the ideal amount of soot deposit calculation.

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

Check that the battery voltage is in the normal range.

Abnormality in the soot calculation area, such as the atmospheric

pressure sensor, within ECU is suspected.

Has a DTC other than P2459 been detected?

Yes – Go to diagnosis procedure of a related DTC.

No – Go to Step 2.

Step 2) Check the DTC detected (Engine ECU) [Diagnostic Tool].

Erase the trouble history.
Set the starter switch to the “LOCK” position.
Make sure the engine ECU main relay is OFF in the diagnostic tool menu. (This cuts off the communication between the diagnostic tool and the engine ECU).
Set the starter switch to the “ON” position.
Select [Engine] and check if DTC has been detected.

Has P2459 been detected?

Yes – Replace the engine ECU.

Clear all past DTCs. Check that no DTC is detected after test drive.

No – Procedure completed.

Clear all past DTCs. Check that no DTC is detected after test drive.