TANK GP-HYDRAULIC 4446810 - Caterpillar

Table 3
Resistance Measurements for the Coolant Level Circuit
Connector and Terminal Terminal
P2-49 (Engine Coolant level)
P2-73 (Aftercooler Coolant level) All of the terminals on the P1 connector
All of the other terminals on the P2 connector
Engine ground stud
Table 4
Troubleshooting Test Steps Values Results
8. Check the Harness Wiring for a Short Circuit
A. Remove electrical power from the ECM.
B. Disconnect the J1/P1 and the J2/P2 ECM connectors. Also, disconnect the connector for the suspect coolant level sensor.
C. Measure the resistance between the terminal of the appropriate sensor in the first column of Table 3 and the terminals in the second column of Table 3.
Note: Wiggle the harness during the measurements in order to reveal an intermittent condition.
Each check of the resistance indicates an open circuit.
Result: Each check of the resistance indicates an open circuit. There is not a short circuit to another wire in the harness. Proceed to Test Step 9.
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 the wire and/or the connector, when possible. Replace damaged parts, if necessary. Verify that the problem is resolved.
STOP
9. Check the Operation of the ECM
Note: The ECM will be tested by opening and shorting the sensor signal input to the digital return input at the J2 ECM connector. This test covers the coolant level sensors for both the engine coolant and the aftercooler coolant.
A. Use a wire removal tool in order to remove the appropriate sensor signal wire and digital return wire from the P2 connector.
B. Fabricate a jumper wire that is long enough to provide a test short circuit across the ECM connector. Crimp connector sockets to each end of the jumper wire.
C. Install the jumper wire into the empty terminal locations.
D. Restore electrical power to the ECM.
E. Use Cat ET to monitor the status for the appropriate “Coolant Level”. Use a wire removal tool to remove the jumper wire and check the status again.
F. Remove electrical power from the ECM.
Restore all wiring to the original configuration.
The status is “LOW” when the jumper wire is not connected. The status is “OK” when the jumper wire is connected.
Result: The status is “LOW” when the jumper wire is not connected. The status is “OK” when the jumper wire is connected.
The ECM is properly reading the switch 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 is “LOW”when the jumper wire is connected.
The ECM is not reading the switch input. Replace the ECM. Refer to Troubleshooting, "ECM - Replace".
STOP