0317422 JOHNSON SEAL, Shift rod, std

Illustration 1 g02156362
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 a plastic cover (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, the supply voltage 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 for a "Coolant Level Installation Status" parameter. If your application has this parameter, ensure that the parameter is set to "Installed". The ECM will then be configured 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.Before you perform this test procedure, ensure that the coolant level is OK.
Illustration 2 g02226833
Typical schematic for the coolant level sensors
Pressurized System: Hot coolant can cause serious burns. To open the cooling system filler cap, stop the engine and wait until the cooling system components are cool. Loosen the cooling system pressure cap slowly in order to relieve the pressure.
Test Step 1. Inspect the Electrical Connectors and the Wiring
Remove electrical power from the ECM.
Illustration 3 g02156432
Location of the coolant level sensors (right side view of radiator tank)
(4) Coolant level (full) sensor
(5) Coolant level (add) sensor (for 773G and 775G only)
(6) Coolant level (low) sensor
Illustration 4 g02156508
Location of the connectors at the ECM(typical front side engine view)
(7) J1/P1 ECM connector
Thoroughly inspect the connector for sensor (4), (5), and (6). Also, thoroughly inspect ECM connector (7). Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Illustration 5 g02156511
Terminal locations at the P1 ECM connector for the coolant level sensor
(P1-4) 8 V supply
(P1-5) Return
(P1-23) Coolant level (full)
(P1-44) Coolant level (add) (for 773G and 775G only)
(P1-45) Coolant level (low)
Illustration 6 g01159881
Terminal locations at the harness connector for the coolant level sensor
(Terminal A) 8 V supply
(Terminal B) Return
(Terminal C) Sensor signal
Perform a 45 N (10 lb) pull test on each of the wires that are associated with the circuit for the coolant level sensor.
Check the allen head screw on each ECM connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values. Expected Result:All connectors, pins, and sockets are coupled and/or inserted, and the harness and wiring are free of corrosion, of abrasion or of pinch points.Results:
OK - The harnesses and the wiring appear to be OK. Proceed to Test Step 2.
Not OK - There is a problem with the connectors and/or the wiring.Repair: 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.STOPTest Step 2. Check the Supply Voltage at the Suspect Sensor Connector
Disconnect the suspect coolant level sensor at the sensor connector.
Restore electrical power to the ECM.
Measure the voltage between terminals A (supply) and B (return) at the harness connector for the coolant level sensor.
Remove electrical power from the ECM. Expected Result:The voltage measurement is 8.0 0.4 VDC.Results:
OK - The voltage measurement is 8.0 0.4 VDC. The supply voltage is reaching the sensor. Proceed to Test Step 3.
Not OK - The voltage measurement is not 8.0 0.4 VDC.Repair: The digital 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".STOPTest Step 3. Short the Signal Wire to Ground and Monitor the Status for "Coolant Level"
Remove electrical power from the ECM.
Fabricate a jumper wire that is long enough to create a short circuit between two terminals at the coolant level sensor harness connector. Crimp connector pins to each end of the jumper wire.
Install the jumper wire between terminals B (return) and C (signal) on the harness side of the connector for the coolant level sensor.
Restore electrical power to the ECM.
Monitor Cat ET while the jumper wire is installed. Check for a 2143 event code to become active. Note: Wait at least 30 seconds for activation of the code.
Remove electrical power from the ECM.
Remove the jumper wire. Connect the harness connector for the coolant level sensor. Expected Result:The 2143 event code becomes active when the jumper wire is installed.Results:
OK - The 2143 event code becomes active when the jumper wire is installed. The ECM and the wiring harness to the coolant level sensor are OK.Repair: Perform the following procedure: