Hino 238, Workshop Manual

Page: 708 / 919

DEF SCR SYSTEM (DCU) 5–142
DTC: P204B
EN01H16F02040F03001032
DTC: P204B DEF pressure sensor - rationality
INFORMATION
1. Technical description
• The pressure sensor in the DEF pump is used to confirm the pressure in the DEF pipe.
<Description of malfunction>
• DEF pressure sensor failure is detected.
2. DTC set condition
(1) DTC detection condition
Starter switch ON.
Minimum DEF pressure during previous afterrun
>
-50 kPa {-7.3 psi}
DEF defrosting is completed, and
Exhaust Gas Temperature (SCR inlet)
<
150

C {302

F}, and
DEF Pressure line No DEF, and
No malfunction
(2) Judgement criteria
DEF pressure
>
50 kPa {7.3 psi} or
<
-50 kPa {-7.3 psi} for 10 sec.
3. Reset condition
• After having restored to the normal conditions.
4. Indication, warning or system control regulation when the DTC is set.
• MIL: ON
•
DEF injection is stopped.
• NOx purification function is stopped.
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.
<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.
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
SAPH16F020400093