Hino 238, Workshop Manual

Page: 774 / 919

DEF SCR SYSTEM (DCU) 5–208
DTC: P20A1
EN01H16F02040F03001044
DTC: P20A1 Reverting valve for DEF pump stuck close
INFORMATION
1. Technical description
• Reverting valve for DEF pump stuck close is checked by DEF pressure.
<Description of malfunction>
• Failure of reverting valve inside DEF pump is detected.
2. DTC set condition
(1) DTC detection condition
Battery voltage is in the range of 10V to 16V.
800 kPa {116 psi}
<
DEF pressure
<
1,050 kPa {152 psi}.
(2) Judgement criteria
The pressure sensor indicates 50 kPa {7.3 psi} or higher 25 seconds after the starter switch is turned OFF.
3. Reset condition
• DEF pump pressure sensor drop to 50 kPa {7.3 psi} is detected within 25 seconds after starter switch is turned OFF.
4. Indication, warning or system control regulation when the DTC is set.
• MIL: ON
•
DEF injector and DEF pipe may rupture when DEF freezes.
5. Symptoms on the vehicle when the DTC is set
<Symptoms on the vehicle due to backup control (fail safe function)>
•
–
<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
•
Malfunction of reverting valve for DEF pump
Supply module
(DEF pump)
DCU
LFQ
(PSR+)
LFR
LGD
(PSRS)
(PSR+)
(PSRS)
LFP LGF
(PSR-)
(PSR-)
LFJ
(PMP+)
LFL
LG8
(PMPS)
(PMP+)
(PMPS)
LFK LGA
(PMP-)
(PMP-)
LFM LGB
(PMV+)
(PMV+)
LFN LGC
(PMV-)
(PMV-)
LGE
LG9
SAPH16F020400135