C175-20 Locomotive Engine Caterpillar

DEF Tank Level Is Low

Usage:

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

Show/hide table

Table 1
J1939 Code and Description	CDL Code and Description	Comments
4367-1 Aftertreatment #1 DEF Tank #2 Level : Low - most severe (3)	E955 (3) Low Aftertreatment #1 DEF Tank #2 Level	The Electronic Control Module (ECM) detects that the DEF quick thaw 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 quick thaw 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 quick thaw 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 quick thaw tank level is not refilling as fast as expected. The code is logged.

Show/hide table

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"

Show/hide table




Illustration 1	g06088493
(1) Bulk Tank (OEM) (2) Quick Thaw Tank Refill Valve (3) Dosing Cabinet (4) Quick Thaw Tank (5) Pump (OEM) (6) Inlet Strainer (7) Filter (OEM)

Probable Causes

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

Recommended Actions

Show/hide table

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 4367-31 code is active. Proceed to Test Step 2.
2. Inspect the Remote Tank and Supply Lines A. Remove electrical power from the engine. B. Visually inspect the remote tank and all the DEF lines between the remote tank and quick thaw tank. C. Inspect the lines to ensure that the lines are connected and routed properly. D. Visually inspect the remote tank DEF level.	DEF Lines	Result: The DEF supply line form the remote tank to the quick thaw tank are connected and routed properly. Proceed to Test Step 3. Result: The DEF supply lines from the remote tank to the quick thaw tank are not connected or routed properly. Repair: Repair or replace the damaged DEF line. Result: The remote tank does not have an adequate level of DEF. Repair: Perform the following procedure: 1. Ensure that there are no DEF leaks. 2. Fill the remote DEF tank. 3. Perform a power cycle of the engine and aftertreatment system. 4. Check for codes. If the problem is not resolved, proceed to Test Step 3.
3. Perform a "DEF Tank Refill Solenoid Override" A. Apply electrical power to the engine. 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 4. Result: The "DEF Tank #2 Level" increased. Verify that the repair eliminated the problem.
4. Replace the DEF Filter and A. Replace the DEF filter and strainer between the remote tank and the quick thaw tank.	DEF Filter	Result: The DEF filter and strainer were replaced. Proceed to Test Step 5.
5. Perform a "DEF Tank Refill Solenoid Override" A. Apply electrical power to the engine. 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. Proceed to Test Step 6.
6. Inspect the DEF Transfer Pump A. Apply electrical power to the engine. 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 7. Result: The DEF transfer pump is operational. Repair: Replace the DEF tank refill valve. Perform the override again. If the problem is not resolved, OEM device troubleshooting.
7. Check the DEF Transfer Pump Relay Control Circuit A. Remove electrical power from the engine. B. Disconnect the DEF transfer pump relay from the wiring harness connector. C. Apply electrical power to the engine. 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).