JLG 1850SJ, Service And Maintenance Manual, Page: 155 / 712

SECTION 3 - CHASSIS & TURNTABLE
3121619 3-105
1864 996 524178 7 The urea pump is not able to control the urea
pressure between 9bar and 11 bar. The urea pump controller is not able to control
the urea pressure between 9bar and 11
bar due to malfunction in the SCR system.
Suspected components:
- DEF pump broken
- Reverting valve continously open
- Urea suction line, backflow line broken or con-
nection swapped
- PWM Powerstage has a defect
- Pump Pressure sensor broken Make sure that DEF lines, pump and tank are not
frozen.
Check for DEF level in the tank
Check DEF lines:
All lines connected? The right lines connected to
the correct places?
Suction line blocked?
Is there any leakage? Not also urea to the out-
side but also air into the lines, especially
in the suction line!
Perform SERDIA usecase "pressure test":
Does the DEF pump work properly? => check
wiring harness & PWM signal for pump
Does the DEF pressure rise?
Is the error healed?
If still unsuccessful so far:
- Check DEF pressure sensor: At ignition on and
SCR system state = 0 ("Init check"),
SCR_pAbsAdapUPmpP shall be identical to
EnvP_p. Fulfilled: Sensor okay!
- Check reverting valve
- Check DEF pump filter: dirt inside?
Suspected components:
DEF pump broken
Reverting valve continously open
DEF suction line, backflow line broken or con-
nection swapped
PWM Powerstage has a defect
DEF pump pressure sensor broken
1865 668 4360 2 Error at static plausibility check:
absolut temperature difference of sensed
temperature upstream SCR catalyst and
ambient temperature > as static plausibility
limit
at engine cold start (engine was off for at
least 8 h), temperature upstream of SCR cat-
alyst is expected to be identical to ambient
temperature => see enable conditions for
details.
Error at dynamic plausibility check:
temperature difference of sensed tempera-
ture upstream SCR catalyst and ambient
temperature < as dynamic plausibility limit
dynamic check is blocked if static plausibility
check is already faulty
=> Temperature upstream SCR catalyst
must be by 40°C higher than ambient tem-
perature if engine runs and a certain delay
time has expired. Error at static plausibility check:
absolut temperature difference of sensed tem-
perature upstream SCR catalyst and
ambient temperature > as static plausibility
limit
at engine cold start (engine was off for at least 8
h), temperature upstream of SCR
catalyst is expected to be identical to ambient
temperature => see enable conditions for
details.
Error at dynamic plausibility check:
temperature difference of sensed temperature
upstream SCR catalyst and ambient
temperature < as dynamic plausibility limit
dynamic check is blocked if static plausibility
check is already faulty
=> Temperature upstream SCR catalyst must
be by 40°C higher than ambient
temperature if engine runs and a certain delay
time has expired. Check whether temperature sensor upstream of
SCR catalyst is physically mounted
within exhaust pipe
If cold start condition can be made sure (engine
was off for at least 8 h) compare
values of EnvT_t, EngDa_tEng, Exh_TOxiCatUs,
Exh_tOxiCatDs and
SCR_tSensUCatUsT at ignition on, without
starting the engine. All identical?
Compare values of Exh_TOxiCatUs,
Exh_tOxiCatDs and SCR_tSensUCatUsT after 15
min in constant operation point: show all simi-
lar values (30 K tolerance width). Are
ambient temperature and (EnvT_t), cooling
water temperature (EngDa_tEng) plausible?
Sensor coated with urea crystalls? Dismount
urea injector and inspect temperature
sensor upstream SCR catalyst visually
Check wiring of sensor
Replace sensor
Table 3-10. Engine Fault Codes
Deutz
Code
Blink
Code
SPN FMI Description Possible Cause Action