0512425 JOHNSON SLEEVE

Illustration 1 g01150024
Components of the coolant level sensor
(1) Sensor
(2) Sensor probe (brass dowel)
(3) Plastic cover Coolant 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 of the sensor. The sensor contains a probe (2) that is covered with plastic (3).When the sensor probe is immersed in coolant, the sensor senses a particular capacitance. The sensor electronics react by sinking the signal to the sensor return (ground).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. The least likely cause is a problem with the ECM.
Illustration 2 g01619864
Typical schematic for the coolant level sensor
Illustration 3 g01471855
Typical location of the coolant level sensor (rear view of shunt tank)
(4) Coolant level sensor
Illustration 4 g01443786
Location of the connectors at the ECM(typical front side engine view)
(5) J2/P2 ECM connector
(6) Left rail connector
(7) J1/P1 ECM connector
Illustration 5 g01443791
Location of the machine interface connector (left rear engine view)
(8) Machine interface connector
Illustration 6 g01681844
Terminal locations at the P2 ECM connector for the coolant level sensor
(P2-18) Digital return
(P2-29) Digital supply
Illustration 7 g01681900
Terminal locations at the P1 ECM connector for the coolant level sensor
(P1-44) Coolant level
(P1-15) Digital return
Illustration 8 g01681880
Terminal locations at the left rail connector for the coolant level sensor
(Terminal 28) Digital supply
(Terminal 31) Digital return
(Terminal 50) Coolant level
Illustration 9 g01661673
Terminal locations at the machine interface connector for the coolant level sensor
(Terminal 15) Digital return
(Terminal 16) Coolant level
(Terminal 33) Digital supply
Illustration 10 g01159881
Terminal locations at the harness connector for the coolant level sensor
(Terminal A) Digital supply
(Terminal B) Digital return
(Terminal C) Sensor signal
Table 1
Troubleshooting Test Steps Values Results
1. Inspect the Electrical Connectors and the Wiring
A. Remove electrical power from the ECM.
B. Thoroughly inspect the connector for sensor (4), ECM connectors (5) and (7), rail connector (6), and machine connector (8). 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. Che