Case 721G Stage IV, Operator'S Manual

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3 - CONTROLS AND INSTRUMENTS
Resetting the Selective Catalytic Reduction (SCR) system
After a failure or warning has been set, the SCR system must perform automatic tests to determine if failures or
warnings have been resolved. There are two categories of system warnings:
1. Electrical failures which only need key cycle to heal.
2. Failures which need an active Urea Dosing System to heal:
• Heated up SCR
• High engine speed and torque
The system must perform the following actions in order to recognize the resolved failures or warnings and reset itself.
1. For DEF/A
D
B
LUE
® level warnings:
a. Key switch must be cycled OFF then ON.
2. For poor DEF/A
D
B
LUE
® quality warnings:
a. Key switch must be cycled OFF then ON.
3. For SCR system warnings, one of the following conditions must occur, depending on the exact cause of the warn-
ing:
a. Requires the machine to be operated for approximately 20 min at a minimum of 50% load to operate the SCR
system.
b. Requires starting and running the engine, but does not require the SCR system to operate.
c. Requires the key switch to be cycled OFF then ON.
Validation re-starts
Validation re-starts apply to the scenario “3a” of SCR system warnings (see list above). Validation re-starts allow
operation of the machine for up to
30 min without power loss after a poor DEF/A
D
B
LUE
® quality or SCR system fault
has been detected. Up to three re-starts are permitted. Re-starts are counted if either of the following conditions are
met:
1. Key off, wait 2 min for ECU after-run.
2. Key on, wait 5 – 15 s
3. Key off, wait 5 – 15 s
4. Key on, wait 5 – 15 s
5. Start
Normal operation will resume if a reset is detected within the 30 min window.
If a reset is not detected within 30 min , power loss will occur as described in the table above.
Validation re-starts are not available 7 min before severe inducement, or if inducement is activated a second time
within 40 h (inducements from low tank level are not considered toward validation restart availability)
If all three validation re-starts have been used and the system has not been reset, see your local authorized dealer
for repair.
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