DEF SCR SYSTEM (DCU)
5–232
2. DTC set condition
(1) DTC detection condition
When stuck in open position
1. Starter switch ON.
When stuck in closed position
2. Coolant cut off valve (DEF tank heater valve) open (DEF defrosts)
Coolant temperature is more than 40
C {104
F}.
(2) Judgement criteria
When stuck in open position
1. DEF tank temperature is more than 75
C {167
F} for 10 seconds (Judged by whether the DEF tank is abnormally
heated.)
When stuck in closed position
2. Rise in the DEF tank temperature after 1,000 to 1,200 seconds in condition 2. above: Within 1
C {33.8
F} (Judged
by the fact that the temperature does not rise even when the DEF tank is heated.)
3. Reset condition
•
When stuck in open position
After having restored to the normal conditions.
•
When stuck in closed position
Temperature rises at least 1°C {33.8
F} 1,000 to 1,200 seconds after valve opens (defrosts).
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
•
If DTC P20B1 is detected simultaneously, start DTC P20B1 inspection first.
•
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
•
Coolant cut off valve (DEF tank heater valve) closed stuck or open stuck
•
Blockage or leakage of coolant pipes
•
Harness disconnection or short-circuit
•
Looseness or unsteady contact of connector
•
DEF tank temperature sensor malfunction
•
Engine coolant temperature sensor malfunction
NOTICE
1. If the heat source is brought close to the DEF tank or the heated DEF is supplied, P20B2 may be detected.
2. "Stuck closed" will be detected only at low temperatures where defrosting of DEF is necessary.
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 ...
