DEF SCR SYSTEM (DCU)
5–253
CHECKLIST: P20B4
DTC: P20B4
DEF tank heater valve - circuit (Circuit high)
Inspection Procedure
Step
Action
Description
Judgement
Check
(Yes/No)
Yes
No
1
Inspect the
coolant cut off
valve connec-
tor
Check the connection of the cool-
ant cut off valve connector
(Looseness and 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 2.
2
Check the
coolant cut off
valve unit
Measure the resistance between
the terminals of the coolant cut off
valve.
<Tester connections>
Coolant cut off valve connector
LDU – LDV
<Standard values>
20
C {68
F}: 9.04
–
9.52
The measure-
ments meet
the standard
value: Go to
YES.
The measure-
ments do not
meet the stan-
dard value: Go
to NO.
Go to step 3.
Replace the
coolant cut off
valve.
Perform "After-
inspection
work" of
INFORMA-
TION section.
3
Check for
short-circuit in
the coolant cut
off valve wire
harness
Disconnect the DCU 86P connec-
tor. Connect the signal check har-
ness to measure the resistance
between the terminals of the DCU
86P vehicle-side connector and
the ground.
<Tester connections>
WMV+
–
Ground
WMV-
–
Ground
<Standard values>
The measure-
ments meet
the standard
value: Go to
YES.
The measure-
ments do not
meet the stan-
dard value: Go
to NO.
Go to step 4.
Repair or
replace the
harness.
Perform "After-
inspection
work" of
INFORMA-
TION section.
4
Check for dis-
connection in
the coolant cut
off valve wire
harness
Measure the resistance of the
wire harness and coolant cut off
valve between the DCU 86P vehi-
cle-side connector and the cool-
ant cut off valve.
1.
Connect the coolant cut off
valve connector.
2.
Connect the signal check
harness to DCU 86P vehi-
cle-side connector and mea-
sure the resistance of the
DCU 86P vehicle-side con-
nector terminals.
<Tester connections>
DCU 86P vehicle-side connector
WMV+ – WMV-
<Standard values>
20
C {68
F}: 9.04
–
9.52
The measure-
ments meet
the standard
value: Go to
YES.
The measure-
ments do not
meet the stan-
dard value: Go
to NO.
Go to step 5.
Repair or
replace the
harness.
Perform "After-
inspection
work" of
INFORMA-
TION section.
Summary of Contents for 238
Page 201: ...ENGINE CONTROL SYSTEM J08E 4 978 Harness disconnection or short circuit ...
Page 215: ...ENGINE CONTROL SYSTEM J08E 4 992 Malfunction of sensor 2 Malfunction of engine ECU ...
Page 301: ...ENGINE CONTROL SYSTEM J08E 4 1078 8 Estimated failure factors Malfunction of engine ECU ...
Page 709: ...DEF SCR SYSTEM DCU 5 143 8 Estimated failure factors DEF pump pressure sensor malfunction ...