Hino 238, Workshop Manual

Page: 806 / 919

DEF SCR SYSTEM (DCU) 5–240
CHECKLIST: P20B2
DTC: P20B2 DEF tank heater valve stuck Inspection Procedure
Step Action Description Judgement
Check
(Yes/No)
Yes No
1
Check the
DTC detected
(DCU) [Hino-
DX] Check if any DTC other than
P20B2 (for example, P20B1,
U02A2) have been detected in
[DCU].
DTC other
than P20B2
(for example,
P20B1) has
been detected:
Go to YES.
No DTC has
been detected:
Go to NO.
Go to diagno-
sis procedure
of a related
DTC.
Go to step 2.
2
Inspect the
DEF tank tem-
perature sen-
sor connector
Check the connection of the DEF
tank temperature sensor connec-
tor (Looseness or poor contact).
Failure found:
Go to YES.
No failure
found: Go to
NO.
Connect
securely,
repair if
needed.
Perform "After-
inspection
work" of
INFORMA-
TION section.
Go to step 3.
3
Inspect the
engine cool-
ant system
(pipes or
hoses)
1. Check for leakage of the
engine coolant system
(pipes or hoses).
2. Check for uncoupled,
clogged, broken, or cracked
parts in the engine cooling
system (pipes and hoses).
Failure found:
Go to YES.
No failure
found: Go to
NO.
Repair or
replace the
faulty part.
Perform "After-
inspection
work" of
INFORMA-
TION section.
Go to step 4.
4
Inspect the
coolant tem-
perature sen-
sor connector
Check the connection of the cool-
ant temperature sensor connector
(Looseness or poor contact).
Failure found:
Go to YES.
No failure
found: Go to
NO.
Connect
securely,
repair if
needed.
Perform "After-
inspection
work" of
INFORMA-
TION section.
Go to step 5.
5
Inspect cool-
ant tempera-
ture sensor
1. Check the installation of the
coolant temperature sensor.
2. Make sure there is no dirt or
damage to the coolant tem-
perature sensor.
Failure found:
Go to YES.
No failure
found: Go to
NO.
Clean the
coolant tem-
perature sen-
sor and install
it properly.
If damaged,
replace the
coolant tem-
perature sen-
sor.
Perform "After-
inspection
work" of
INFORMA-
TION section.
Go to step 6.