5035076 JOHNSON SLIDER, SHIFT HORIZONTAL

Illustration 1 g01132350
Coolant level sensor (1) Sensor (2) Brass rod (3) Plastic coverCoolant level sensor (1) contains no moving parts. The sensor detects variations in capacitance. The sensor's probe contains a brass rod (2) that is covered with plastic (3) . The brass rod is one plate of a capacitor. The plastic cover is the capacitor's dielectric. The coolant is the other plate of the capacitor.When the probe is immersed in coolant, the sensor senses a particular capacitance. The sensor responds by creating a short circuit between the signal wire and the ground wire.When the probe is not immersed in coolant, the capacitance value changes. The change in the capacitance value is detected by the sensor's electronic circuits. The circuits apply approximately +5 VDC to the signal wire. The ECM detects the voltage and the ECM activates a E059 event code.A E059 event code is probably caused by a low coolant level. The next likely cause is a problem with a wiring harness or with the sensor. The least likely cause is a problem with the ECM.
Illustration 2 g01136733
Schematic for the circuit for coolant level sensor
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
Turn the keyswitch to the OFF position.
Illustration 3 g01132749
Engine components for the coolant level sensor (1) J1/P1 connectors (2) J2/P2 connectors (3) Coolant level sensor
Thoroughly inspect connectors (1) and (2) . Inspect the connectors for sensor (3) . Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Illustration 4 g01136740
P2 terminals that are associated with the coolant level sensor (P2-14) Return (P2-29) +8 VDC (P2-49) Coolant level
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 completely coupled and/or inserted, and the harness and wiring are free of corrosion, of abrasion or of pinch points.Results:
OK - The connectors and wiring are 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.Verify that the repair eliminates the problem.STOPTest Step 2. Check the Supply Voltage at the Sensor Connector
Disconnect the coolant level sensor.
Turn the keyswitch to the ON position.
Illustration 5 g01132478
Harness connector for the coolant level sensor (A) +8 VDC (B) Return
Measure the voltage between terminals A (+8 VDC) and B (Return) at the harness connector for the coolant level sensor.
Turn the keyswitch to the OFF position.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. The digital sensor supply voltage is not reaching the sensor.Repair: Refer to Troubleshooting, "Digital Sensor Supply Circuit - Test".STOPTest Step 3. Check the Coolant Level
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.
Stop the engine.
After allowing the engine to cool, check the coolant level. Refer to the Operation and Maintenance Manual for the proper procedure to check the coolant level.Expected Result:The coolant is at the proper level.Results:
OK - The coolant is at the proper level. Proceed to Test Step 4.
Not OK - The coolant level is low.Repair: Add coolant according to the procedure in the Operation and Maintenance Manual.Verify that the repair eliminates the problem. Identify the source of the coolant leak and fix the problem.STOPTest Step 4. Disconnect the Coolant Level Sensor and Monitor the Status of "Coolant Level"
Connect the Caterpillar Electronic Technician (ET) to the service tool connector. Refer to Troubleshooting, "Electronic Service Tools".
Disconnect the J800/P800 connectors.
Turn the keyswitch to the ON position.
Monitor the status of "Coolant Level" on Cat ET.
Turn the keyswitch to the OFF position.Expected Result:The status changes from "OK" to "Low" when the sensor is disconnected.Results:
OK - The status is "Low" when the sensor is disconnected. Proceed to Test Step 5.
Not OK - The status is "OK" when the sensor is disconnected. Proceed to Test Step 6.Test Step 5. Short the Harness and Monitor the Status of "Coolant Level"
Turn the keyswitch to the ON position and monitor the status of "Coolant Level" on Cat ET.
Install a jumper wire between terminals B (Return) and C (Signal) on the harness connector for the coolant level sensor.
Monitor the status of "Coolant Level" on Cat ET while the jumper wire is installed.