Error code News Shared knowledge

Hino P2458 Fault Code: Fault In Manual Regeneration

21/11/2025

Technical Description

The DPR performs PM regeneration by increasing DOC temperature using the engine warm up control.
During a manual regeneration, warm up control is carried out by idle up, exhaust brake closing, VNT control, after injection, post injection and dosing valve injection.

Description of malfunction

In a manual regeneration, the DOC and ATC temperatures do not increase to the post injection-enabled region even after the specified time.

DTC set condition

DTC Detection Condition:

Battery voltage is in the range of 10 V to 16 V.
The engine speed remains at 500 r/min or more.
DPR manual regenerating.
Do not detect the exhaust gas temperature sensor 4 (DPR inlet) of failure.

Judgment Criteria:

After a manual DPR regeneration is started, the DOC temperature is still below 200°C {392°F} and the ATC temperature is still below 230°C {446°F} even after 30 minutes.

Reset condition

DPR memory is reset by the diagnostic tool.

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

MIL: OFF
SVS light: ON

Symptoms on the vehicle when the DTC is set

Symptoms on the vehicle due to malfunction

Do not DPR regeneration.

Pre-inspection work

Check that the battery voltage is in the normal range.

After-inspection work

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

Possible causes

Drop in injection quantity of fuel injection system.

Failure of VNT system.

Exhaust gas temperature sensor 4 (DPR inlet):

Loose/disconnected sensor of failure in sensing area (contamination, clogging or damaged).
Abnormal resistance of sensor.
Failure in engine ECU sensor power supply.

Exhaust gas temperature sensor 1 (ATC upstream)

Loose/disconnected sensor of failure in sensing area (contamination, clogging or damaged).
Abnormal resistance of sensor.
Failure in engine ECU sensor power supply.

Exhaust gas temperature sensor 1 (ATC upstream)

Loose/disconnected sensor of failure in sensing area (contamination, clogging or damaged).
Abnormal resistance of sensor.
Failure in engine ECU sensor power supply.

Exhaust brake

Malfunction of exhaust brake.
Improper adjustment of exhaust brake (The difference between the injection quantities in active and inactive conditions is out of the standard).

Gas leaks in the middle of the exhaust system.

Failure of coolant temperature sensor (low temperature stuck).

Inspection procedure

Troubleshooting steps

Step 1

Check the DTC detected1 [Diagnostic Tool].

Set the starter switch to the “LOCK” position.
Connect the vehicle to the diagnostic tool.
Set the starter switch to the “ON” position.
Select [Engine] and check if any DTC other than P2458 has been detected.

Has DTCs other than P2458 been detected?

Yes – Go to diagnosis procedure of a related DTC.

No – Go to Step 2.

Step 2

Inspect the exhaust pipe.

Check for exhaust pipe crack (between the turbocharger and DPR), exhaust gas leak (soot contamination) and improper coupling flange tightening.

Yes – Repair of exhaust pipe (replace gasket, retighten), replace if needed.

No – Go to Step 3.

Step 3

Inspect the exhaust brake valve.

Check the exhaust brake valve for unease and sticking.

Were any failures found?

Yes – Clean the exhaust brake valve.

Replace if necessary.

After cleaning or replacement, go to Step 4.

No – Go to Step 4.

Step 4

Inspect the fuel injection quantity [Diagnostic Tool].

Warm up the engine. (Coolant temperature: 80°C {176°F} or more).
Turn OFF the devices that place load on the engine, such as the air conditioner.

Inspection Procedure:

Select [Engine] on the screen of the diagnostic tool.
Select [Data monitor setting] and [Active test setting].
Select [Target rpm] from [Active test setting] and set the engine revolution to 980 r/min.
Select [Injection quantity] from [Data monitor setting].
Turn ON/OFF the exhaust brake switch and check the difference between the injection quantity of the injector while the exhaust brake is working and the injection quantity when the exhaust brake is not actuated.

MEASUREMENT CONDITIONS

STANDARD VALUES

Engine revolution: 980 r/min

Engine coolant temperature:

80°C {176°F} or more

Turn OFF the air conditioner, and other

devices that place load on the engine.

10 – 14 mm3/st

Is the measured value within the standard values? (There shall be a change in

the injection quantity between while the exhaust brake is working and when it is not actuated).

Yes – Go to Step 5.

No – Adjust the butterfly opening of the exhaust brake.

Step 5

Inspect the exhaust gas temperature sensor 4 (DPR inlet).

Inspect the exhaust gas temperate sensor 4 (DPR inlet) for improper installation.
Check the sensing area of the exhaust gas temperature sensor 4 (DPR inlet) for dirt, clogging, and damage.

Were any failures found?

Yes – Clean the sensing area and install the sensor properly. If damage is found, replace the sensor.

No – Go to Step 6.

Step 6

Inspect the exhaust gas temperature sensor 4 (DPR inlet) unit.

Disconnect the exhaust gas temperature sensor 4 (DPR inlet) connector.
Use the electrical tester to measure the resistance between the terminals of the exhaust gas temperature sensor 4 (DPR inlet).

MEASUREMENT CONDITIONS

TESTER CONNECTIONS

STANDARD VALUES

Starter switch: LOCK

Exhaust gas temperature sensor 4 (DPR inlet)

TEX1 – GND1

20°C {68°F}: 13.7 – 29.8 kΩ

50°C {122°F}: 7.13 – 13.7 kΩ

80°C {176°F}: 4.1 – 7.13 kΩ

Do the measurements meet the standard value?

Yes – Go to Step 7.

No – Replace the exhaust gas temperature sensor 4 (DPR inlet).

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

Step 7

Inspect the exhaust gas temperature sensor 1 (ATC upstream).

Inspect the exhaust gas temperate sensor 1 (ATC upstream) for improper installation.
Check the sensing area of the exhaust gas temperature sensor 1 (ATC upstream) for dirt, clogging, and damage.

Were any failures found?

Yes – Clean the sensing area and install the sensor properly.

If damage is found, replace the sensor.

No – Go to Step 8.

Step 8

Inspect the exhaust gas temperature sensor 1 (ATC upstream) unit.

Set the starter switch to the “LOCK” position.
Disconnect the exhaust gas temperature sensor 1 (ATC upstream) connector.
Use the electrical tester to measure the resistance between the terminals of the exhaust gas temperature sensor 1 (ATC upstream).

MEASUREMENT CONDITIONS

TESTER CONNECTIONS

STANDARD VALUES

Starter switch: LOCK

Exhaust gas temperature sensor 1 (ATC upstream)

TEX3 – GND3

20°C {68°F}: 13.7 – 29.8 kΩ

50°C {122°F}: 7.13 – 13.7 kΩ

80°C {176°F}: 4.1 – 7.13 kΩ

Do the measurements meet the standard value?

Yes – Go to Step 9.

No – Replace the exhaust gas temperature sensor 1 (ATC upstream).

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

Step 9

Inspect the DPR filter.

Remove DPR filter and check that there is no soot leaking at the rear edge of the DPR filter, no damage, and no other abnormality.
Insert the check probe from the rear surface to inspect the inside.
Check probe inserting depth.

STANDARD VALUES

175 – 185 mm {6.890 – 7.283 in.}

Were any failures found?

Yes – Replace the DPR filter and the PM sensor.

After replace, perform DPR manual regeneration.

No – Go to Step 10.

Step 10

Inspect the coolant temperature sensor.

Inspect the coolant temperature sensor for improper installation.
Check the sensing area of the coolant temperature sensor for dirt, clogging, and damage.

Were any failures found?

Yes – Clean the sensing area and install the sensor properly.

If damage is found, replace the sensor.

No – Go to Step 11.

Step 11

Inspect the coolant temperature sensor unit.

Set the starter switch to the “LOCK” position.
Disconnect the engine coolant temperature sensor connector.
Use the electrical tester to measure the resistance between the terminals of the engine coolant temperature sensor.

MEASUREMENT CONDITIONS

TESTER CONNECTIONS

STANDARD VALUES

Starter switch: LOCK

Engine coolant temperature

sensor THW – E

20°C {68°F}: 2.59 – 2.32 kΩ

80°C {176°F}: 0.326 – 0.310 kΩ

Do the measurements meet the standard value?