GASKET 2P1273 - Caterpillar

Use this procedure to troubleshoot any suspect problems with the circuit for the coolant level sensor.The coolant level sensor monitors the engine coolant level in order to warn the operator when the coolant level is low.
Illustration 1 g01150024
Components of the coolant level sensor
(1) Sensor
(2) Sensor probe (brass dowel)
(3) Outer coating When the probe is not immersed in coolant, approximately +5 VDC is sourced to the signal wire. When this condition is detected by the Electronic Control Module (ECM), an event code is activated.Prior to troubleshooting any problems with the coolant level sensor, use Caterpillar Electronic Technician (ET) to check the installation status for the sensor. The coolant level sensor configuration parameter must be set to "Installed" in order for the ECM to monitor the signal from the sensor.The activation of an event code and/or a warning lamp is probably caused by a low coolant level. The next likely cause is a problem with the wiring harness, a connector, or the sensor.
Illustration 2 g02949436
Illustration 3 g02090761
Terminal locations at the harness connector for the coolant level sensor
(Terminal A) Sensor supply
(Terminal B) Sensor return
(Terminal C) Sensor signal
Table 1
Troubleshooting Test Steps Values Results
1. Inspect the Electrical Connectors and the Wiring
A. Turn the main disconnect switch to the OFF position.
B. Thoroughly inspect the ECM connectors and all other connectors connected with the sensors. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
C. Perform a 45 N (10 lb) pull test on each of the wires that are associated with the circuit for the coolant level sensor.
D. Check the allen head screw on each ECM connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
Electrical Connectors and the Wiring
Result: The harnesses and the wiring appear to be OK.
Proceed to Test Step 2.
Result: There is a problem with the connectors and/or the wiring.
Repair: The wiring and connectors or replace the wiring or the connectors. Ensure that all of the seals are properly connected.
Verify that the repair eliminates the problem.
2. Check the Supply Voltage at the Sensor Connector
A. Disconnect the coolant level sensor at the sensor connector.
B. Restore electrical power to the ECM.
C. Measure the voltage between terminals A (supply) and B (return) at the harness connector for the coolant level sensor.
D. Turn the main disconnect switch to the OFF position.
8.0 0.2 VDC
Result: The voltage measurement is 5.0 0.4 VDC.
The supply voltage is reaching the