3516B and 3516C Engines For MT4400D AC Off-Highway Trucks Caterpillar

Oil Level - Test

Usage:

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Table 1
Diagnostic Codes Table
Code and Descriptions	Conditions which Generate this Code	System Response
98-18 Engine Oil Level: Low - moderate severity (2)	The engine oil level has dropped below the level of the sensor for the time specified in the ECM.	The code is logged. The ECM may derate the engine or shutdown the engine.
98-1 Engine Oil Level: Low - most severe (3)
E171(2) Low Engine Oil Level : moderate severity	The engine oil level has dropped below the level of the sensor for the time specified in the ECM.	The code is logged. The ECM may derate the engine or shutdown the engine.
E171(3) Low Engine Oil Level : most severe

System Operation

Use this procedure to troubleshoot any suspect problems with the engine oil level sensor circuit.

The ECM monitors the engine oil level prior to the engine starting.

The most likely cause of a code is a problem with an electrical connector or wiring. The least likely cause of a code is the ECM.

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Illustration 1	g03254876
Location of the oil level sensor

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Illustration 2	g03254796
(1) Sensor (2) Sensor probe (brass dowel) (3) Plastic cover

Oil level sensor (1) contains no moving parts. The sensor provides the same function as a switch. The state of the switch is dependent on the capacitance value that is detected at the probe sensor. The sensor contains a probe (2) that is covered with a plastic cover (3) .

When the sensor probe is immersed in oil, the sensor senses a particular capacitance. The sensor electronics react by sinking the signal to the return (ground). When the probe is not immersed in oil, the supply voltage is sourced to the signal wire.

Probable Causes

Low engine oil level
Problem with an electrical connection or with the wiring
Problem with the oil level sensor

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Illustration 3	g03366526
Engine oil level sensor schematic

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Illustration 4	g03254376
(P1-4) 8 V supply (P1-18) 8 V return (P1-35) Sensor signal

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Illustration 5	g01159881

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Table 2
Troubleshooting Test Steps	Values	Results
1. Low Engine Oil Level A. Check the engine oil level in the crankcase.	Oil level	Result: The engine oil level is low. Repair: Add engine oil in order to obtain the correct engine oil level. Refer to Operation and Maintenance Manual, "Engine Oil" for the recommendations of engine oil. Start the engine. Inspect the exterior of the engine for oil leaks. Repair any oil leaks. Verify that the repair eliminated the problem. Note: If you suspect that the engine is consuming an excessive amount of engine oil, refer to Troubleshooting, "Oil Consumption Is Excessive". Result: The engine oil is not low. Proceed to Test Step 2.
2. Electrical Connections or Wiring A. Remove electrical power from the ECM. B. Thoroughly inspect the electrical connectors and all of the wiring for the switch. Refer to Troubleshooting, "Electrical Connectors - Inspect" and refer to the electrical Schematic.	Electrical connections	Result: The electrical connections and the wiring appear to be OK. Proceed to Test Step 3. Result: There is a problem with the connectors and/or wiring. Repair: Perform the necessary repairs to the connectors and/or wiring. Verify that the repair eliminated the problem.
3. Check the Supply Voltage at the Sensor Connector A. Disconnect the oil level sensor connector. B. Restore electrical power to the ECM. C. Measure the voltage between terminals A (supply and B (return) at the harness connector of the oil level sensor. D. Remove electrical power from the ECM.	Sensor	Result The voltage measurement if 8.0 ± 0.4 VDC. The supply voltage is reaching the sensor. The supply voltage is OK. Result The voltage measurement is not 8.0 ± 0.4 VDC. Repair: The sensor supply voltage is not reaching the sensor. There is a problem in the circuit for the digital sensor supply. Refer to Troubleshooting, "Sensor Supply - Test". STOP
4. Create a Short at the Sensor Connector A. Remove the electrical power from the ECM. B. Disconnect the oil level sensor connector. C. Use a wire jumper to create a short between terminal 1 (signal) and terminal 2 (sensor return) on the harness side of the connector. D. Restore the electrical power to the ecm. E. Check the status of the "Engine Off Oil Level" parameter to change as the jumper wire is connected. Note: Wait at least 30 seconds in order for the status of the parameter to update. G. Remove the jumper wire. Connect the harness for the oil level sensor.	Open	Result: The status of the "Engine Off Oil Level" parameter changes when the jumper wire is installed. The ECM and the wiring harness to the oil level sensor are OK. Repair: 1. Drain the oil below the level of the oil level sensor. 2. Restore the electrical power to the ECM. 3. Monitor Cat ET. Check for the status of the "Engine Off Oil Level to change. Note: Wait at lease 30 seconds for the status of the parameter to change. 4. Remove electrical power from the ECM. Result: The status of the "Engine Off Oil Level" changed . The oil level sensor is OK. There may be an intermittent problem in the harness or in a connector. Add engine oil in order to obtain the correct engine oil level. Refer to the Operation and Maintenance Manual, "Engine Oil". Return the engine to service. If an intermittent problem is suspected, refer to Troubleshooting, "Electrical Connectors - Inspect" for troubleshooting information. Proceed to Test Step 5 Result: The status of the "Engine Off Oil Level" did not change. Repair: Replace the oil level sensor. Verify that the repair eliminated the problem.
5. Check for an Open Circuit in the Wiring Harness A. Remove electrical power from the ECM. B. Disconnect the J1/P1 ECM connector and the oil level sensor connector. C. Fabricate a jumper wire that is long enough to create a test circuit between the ECM connector and the sensor connector. Crimp a connector pin to one end of the jumper wire. D. Install the jumper wire connector pin into terminal C on the harness side of the connector for the oil level sensor. E. Measure the resistance between the terminal for the signal of the sensor and the loose end of the jumper wire at the J1/P1 connector.	Short	Result: The resistance measurement indicates a short circuit for the signal wire. There is not an open circuit in the harness wire for the sensor signal. Proceed to Test Step 6. Result: The measurement did not indicate a short circuit. Repair: There is an open circuit or excessive resistance in the harness or the connectors. Repair the wire and/or the connector. Replace damaged parts, if necessary. Verify that the repair eliminated the problem. STOP
6. Check the Harness Wiring for a Short Circuit A. Remove electrical power from the ECM. B. Disconnect the J1/P1 ECM connector. Also, disconnect the oil level sensor connector. C. Measure the resistance between the P1-35 at the ECM and all terminals of the P1 and P2 connectors, and the engine ground stud.	Open	Result: Each resistance measurement indicates an open circuit. There is not a short the circuit to another wire in the harness. The harness is OK. Proceed to Test Step 7. Result: At least one check of the resistance does not indicate an open circuit. There is a short to another wire in the harness. The problem may be with a connector. Repair: Repair the wire and/or the connector. Replace damaged parts, if necessary. Verify that the repair eliminated the problem. STOP
7. Check the Operation of the ECM A. Fabricate a jumper wire that is long enough to provide a test circuit across the ECM connectors. Crimp connector sockets onto each end of the jumper wire. B. Use a wire removal tool to remove the wires from terminal locations P1-35 (engine oil level) and P1-18 (return) from the J1/P1 connector. Install the jumper wire into the removed terminal locations. C. Restore electrical power to the ECM. D. Use Cat ET to monitor the status of the "Engine Off Oil Level" parameter. Use a wire removal tool to remove the jumper wire and check the status again. Note: Wait at least 30 seconds for the status of the parameter to change. E. Remove electrical power from the ECM. Restore all wiring to the original configuration.	ECM	Result: The status of the "Engine Off Oil Level" parameter changes with the jumper wire connected. The ECM is OK. Repair: The ECM is properly reading the sensor input. There may be an intermittent problem in the harness or in a connector. If an intermittent electrical problem is suspected, refer to Troubleshooting, "Electrical Connectors - Inspect" for troubleshooting information. STOP Result: The status of the "Engine Off Oil Level" parameter did not change with the jumper wire connected. Repair: The ECM is not reading the sensor input. There may be a problem with the ECM. Before you consider replacing the ECM, consult the Dealer Solutions Network (DSN) for assistance. STOP

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).