Selective Catalytic Reduction Retrofit Aftertreatment Caterpillar

DEF Tank Level Is Low

Usage:

SCR EF5

Use this procedure to troubleshoot a problem with the Diesel Exhaust Fluid (DEF) tank level. Also, use this procedure if one of the following event codes is active or logged.

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Table 1
J1939 Code and Description	CDL Code and Description	Comments
1761-1 Aftertreatment #1 DEF Tank Level : Low - most severe (3)	E954 (3) Low Aftertreatment #1 DEF Tank #1 Level	The Electronic Control Module (ECM) detects that the remote Diesel Exhaust Fluid (DEF) tank level is lower than a threshold. The code is logged.
1761-17 Aftertreatment #1 DEF Tank Level : Low - least severe (1)	E954 (1) Low Aftertreatment #1 DEF Tank #1 Level	The ECM detects that the remote DEF tank level is lower than a threshold. The code is logged.
1761-18 Aftertreatment #1 DEF Tank Level : Low - moderate severity (2)	E954 (2) Low Aftertreatment #1 DEF Tank #1 Level	The ECM detects that the remote DEF tank level is lower than a threshold. The code is logged.
4367-1 Aftertreatment #1 DEF Tank #2 Level : Low - most severe (3)	E955 (3) Low Aftertreatment #1 DEF Tank #2 Level	The ECM detects that the DEF buffer tank level is below a threshold. The code is logged.
4367-17 Aftertreatment #1 DEF Tank #2 Level : Low - least severe (1)	E955 (1) Low Aftertreatment #1 DEF Tank #2 Level	The ECM detects that the DEF buffer tank level is below a threshold. The code is logged.
4367-18 Aftertreatment #1 DEF Tank #2 Level : Low - moderate severity (2)	E955 (2) Low Aftertreatment #1 DEF Tank #2 Level	The ECM detects that the DEF buffer tank level is below a threshold. The code is logged.
4367-31 Aftertreatment #1 DEF Tank #2 Level	E1589 (2) Low Aftertreatment #1 DEF Tank #2 Level	The ECM detects that the DEF buffer tank level is not refilling as fast as expected. The code is logged.

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Table 2
Associated Codes
J1939 Code	CDL Code	Troubleshooting Procedure
4367-3	3131-3	Troubleshooting, "DEF Tank Sensor - Test"
4367-4	3131-4	Troubleshooting, "DEF Tank Sensor - Test"
5434-3	N/A	Troubleshooting, "Solenoid Valve - Test"
5434-4	N/A	Troubleshooting, "Solenoid Valve - Test"

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Illustration 1	g03738409
(1) Remote tank (2) DEF tank refill valve (3) Buffer tank (4) DEF transfer pump (optional) (5) DEF filter

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Illustration 2	g06096192
(6) DEF filter

Probable Causes

DEF level
Sensor
DEF lines
DEF filter
Transfer pump (if equipped)
Relay circuit

Recommended Actions

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Table 3
Troubleshooting Test Steps	Values	Results
1. Check for Codes A. Connect Cat^® Electronic Technician (ET) to the service tool connector. B. Look for active codes that are associated with the system for the event code.	Codes	Result: An associated code is active. Repair: Troubleshoot any associated codes before continuing with this test. Result: An E955, E1589, 4367-1, 4367-17, 4367-18, or 4368-31 code is active. Proceed to Test Step 4. Result: An E951 (1) or 1761-17 code is active. Proceed to Test Step 2.
2. Check the Remote Diesel Exhaust Fluid (DEF) Tank Level A. Visually inspect the level of DEF in the Remote DEF tank.	DEF Level	Result: The remote DEF Tank level is not below the low DEF level switch. Proceed to Test Step 3. Result: The remote DEF tank level is below the low DEF level switch. Repair: Add DEF to the remote DEF tank. If the problem is not resolved, proceed to Test Step 3.
3. Check for Codes A. Turn the DC breaker to the ON position. B. Connect Cat ET. C. Determine if a code is active or logged.	Codes	Result: An E951 (1) or 1761-17 code is logged. Return to service. Result: An E951 (1) or 1761-17 code is active. Repair: There is a short to ground in the wiring harness between the remote DEF tank level switch and the Selective Catalyst Reduction (SCR) controller. Repair or replace the wiring harness. Verify that the repair eliminated the problem.
4. Inspect the Remote Tank and Supply Lines A. Turn the DC breaker to the OFF position. B. Visually inspect the remote tank and all the DEF lines between the remote tank and buffer tank. C. Inspect the lines to ensure that the lines are connected and routed properly.	DEF Lines	Result: The DEF supply line form the remote tank to the buffer tank are connected and routed properly. Proceed to Test Step 5. Result: The DEF supply lines from the remote tank to the buffer tank are not connected or routed properly. Repair: Repair or replace the damaged DEF line. If the problem is not resolved, proceed to Test Step 5.
5. Perform a "DEF Tank Refill Solenoid Override" A. Turn the DC breaker to the ON position. B. Connect Cat ET. C. Use Cat ET to perform the following override: - "DEF Tank Refill Solenoid Override" D. Use Cat ET to monitor the following: - "DEF Tank #2 Level" Note: After the "DEF Tank #2 Level" reaches 90 percent, the override will automatically turn off.	DEF Level	Result: The "DEF Tank #2 Level" did not increase. Proceed to Test Step 6. Result: The "DEF Tank #2 Level" increased. Verify that the repair eliminated the problem.
6. Replace the DEF Filter and clean the DEF filter screen. Refer Illustration 2 to locate the filter and filter screen. A. Replace the DEF filter between the remote tank and the dosing cabinet. B.Clean or replace the DEF filter screen (6) at the DEF inlet of the dosing cabinet. If the DEF filter screen is damaged, replace the filter screen. Refer to Operation and Maintenance Manual, "Filter Screen (DEF) - Inspect/Clean" for information regarding the DEF filter screen cleaning and replacement.	DEF Filter	Result: The DEF filter was replaced and the DEF filter screen was cleaned or replaced. Proceed to Test Step 7.
7. Perform a "DEF Tank Refill Solenoid Override" A. Turn the DC breaker to the ON position. B. Connect Cat ET. C. Use Cat ET to perform the following override: - "DEF Tank Refill Solenoid Override" D. Use Cat ET to monitor the following: - "DEF Tank #2 Level" Note: After the "DEF Tank #2 Level" reaches 90 percent, the override will automatically turn off.	DEF Level	Result: The "DEF Tank #2 Level" increased. Return to service. Result: The "DEF Tank #2 Level" did not increase and the system is not equipped with a DEF transfer pump. Repair: Replace the DEF tank refill valve. Verify that the repair eliminated the problem. Result: The "DEF Tank #2 Level" did not increase and the system is equipped with a DEF transfer pump. Proceed to Test Step 8.
8. Inspect the DEF Transfer Pump A. Turn the DC breaker to the ON position. B. Connect Cat ET. C. Use Cat ET to perform the following override: - "DEF Tank Refill Solenoid Override" D. Verify that the DEF transfer pump turns on.	Transfer Pump	Result: The DEF transfer pump is not operational. Proceed to Test Step 9. Result: The DEF transfer pump is operational. Repair: Replace the DEF tank refill valve. Perform the override again. If the problem is not resolved, proceed to Test Step 9.
9. Check the DEF Transfer Pump Relay Control Circuit A. Turn the DC breaker to the OFF position. B. Disconnect the DEF transfer pump relay from the wiring harness connector. C. Turn the DC breaker to the ON position. D. Connect Cat ET. E. Use Cat ET to perform the following override: - "DEF Tank Refill Solenoid Override" F. Measure the voltage on the control side of the relay.	Relay Circuit	Result: There is battery voltage on the control side of the relay. Repair: The control side of the circuit is good. For information on DEF transfer pump, refer to the Original Equipment Manufacturers (OEM) service information. Verify that the repair eliminated the problem. Result: There is NOT battery voltage on the control side of the relay. Repair: There is a problem with the wiring between the DEF transfer pump relay and the ECM. Repair or replace the wiring harness. Verify that the repair eliminated the problem.

If the procedure did not correct the issue, contact your Cat dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).