Hino P20F4 Fault Code: DEF Injector Abnormal

TECHNICAL DESCRIPTION

• The amount of added DEF is diagnosed as abnormal.
• The amount of added DEF is controlled by the DEF pressure and the opening of the DEF injector.

DTC SET CONDITION

DTC Detection Condition:

During System Operation:

• DEF injector duty is > 15% − Accumulated DEF injector duty is > 25,000
• Ratio (= Accumulated DEF pump duty/Accumulated DEF injector duty) is < 0.12

Judgment Criteria:

At System Running:

• Pressure line check start: DEF pump speed: keep and DEF injector: full open
• If DEF pressure is > 750 kPa {109 psi} after 4 sec. from DEF injector open.
• DTC is detected.

RESET CONDITION

After having restored to the normal conditions.

INDICATION, WARNING OR SYSTEM CONTROL REGULATION WHEN THE DTC IS SET

• MIL: ON
• SCR malfunction light: ON
• DEF injection is stopped.
• NOx reduction quantity monitoring is aborted.
• Công suất bị giảm ngay lập tức.
• If malfunction does not improve within 50 min.: vehicle speed is restricted.

SYMPTOMS ON THE VEHICLE WHEN THE DTC IS SET

Symptoms on the Vehicle Due to Backup Control (Fail Safe Function):

• Exhaust gas purification function is declined.
• Engine output is insufficient.
• Vehicle does not speed up (when malfunction does not improve within 50 min.).

PRE-INSPECTION WORK

Check that the battery voltage is in the normal range.

AFTER-INSPECTION WORK

• Clear all past DTCs.
• Check if no DTC is stored after test drive.

POSSIBLE CAUSES

• Clogging of the DEF injector
• Clogging of the DEF pipe.

INSPECTION PROCEDURE

TROUBLESHOOTING STEPS

Step 1) Inspect the DEF pipe (pump ↔ injector).

Check the DEF pipe (pressure line) and check if there are no disconnections, clogging, corrosion, or cracks. Was any failure found ?

Step 2) Inspect DEF injector 1 [Diagnostic Tool].

NOTE: Prepare a beaker or similar, plus a larger measuring vessel for measuring the DEF to be injected, before performing this inspection.

(If the vessel is small, there is dispersion at the time of injection from the injector, and the measuring quantity decreases.)

1. Set the starter switch to the “LOCK” position.
2. Remove the DEF injector from the muffler.
   • NOTE: Refer to the removal and installation information for the DEF injector.
3. Connect the vehicle to the diagnostic tool.
4. Set the starter switch to the “ON” position.
5. Select [DCU].
6. Select [Inspection Menu] on the diagnostic tool menu and check the operation of the DEF injector.

• Inspection Procedure:
• Select [Inspection Menu].
• Select [DEF solution addition test].
• Perform addition test as instructed on the diagnostic tool screen. (Perform all three patterns)

NOTE: When the DEF tank temperature is -5°C (23°F) or lower, perform warm-up to raise it to 10°C (50°F) or higher.. Is operation normal ?

Step 3) Inspect the DEF injector 2 [Diagnostic Tool].

1. Set the starter switch to the “LOCK” position.
2. Replace DEF injector with a new one. (Do not install it on the muffler.)
3. Set the starter switch to the “ON” position.
4. Perform DEF addition test as same as Step 2.

Is operation normal ?

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