Hino 238, Workshop Manual

Page: 822 / 919

DEF SCR SYSTEM (DCU) 5–256
Normal pressure behavior
3. Reset condition
•
After having restored to the normal conditions.
4. Indication, warning or system control regulation when the DTC is set.
•
MIL: ON
• SCR System failure lamp: ON
•
DEF injection is stopped.
• NOx purification function is stopped.
•
If malfunction does not improve within 500 miles: engine output is restricted.
• If malfunction does not improve within 2,000 miles: vehicle speed is restricted.
5. Symptoms on the vehicle when the DTC is set
<Symptoms on the vehicle due to backup control (fail safe function)>
• Exhaust gas purification function has deteriorated.
•
Engine output is insufficient (when malfunction does not improve within 500 miles).
• Vehicle does not speed up (when malfunction does not improve within 2,000 miles).
<Symptoms on the vehicle due to malfunction>
•
–
6. Pre-inspection work
• Check if the battery voltage is in the normal range.
7. After-inspection work
•
Clear all past DTCs.
• Check if no DTC is stored after test drive.
8. Estimated failure factors
• DEF in the DEF tank is empty.
•
Strainer in the DEF sensor is clogged.
• Air is entering into DEF suction line.
•
DEF suction line is clogged, and DEF is leaking from DEF suction line.
• DEF pump filter is clogged.
•
Leak from DEF pump.
• DEF pump malfunction.
SAPH16F020400172