This fault is recorded when the all wheel drive ECM receives a high temperature signal from the hydraulic oil temperature switch. The hydraulic oil temperature switch is a normally closed switch. This fault is caused by the following conditions.
- There is a mechanical problem in the hydraulic system.
- There is a bad ground connection to the frame or wire 202-BK is open.
- The hydraulic temperature switch is faulty.
- Wire 482-WH is open in the machine harness.
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| Illustration 1 | g00549222 |
HYDRAULI OIL TEMPERATURE SWITCH GRAPHIC | |
Reference: Refer to Troubleshooting, "Hydraulic Temperature Switch".
System Response:
This fault can be active when the key start switch is turned ON. The all wheel drive system will continue to operate while this fault is active. The all wheel drive ECM will not enter the diagnostic operating mode. The alert indicator for the hydraulic temperature will flash. If the all wheel drive system is operating, the all wheel drive ECM will attempt to reduce the temperature of the hydraulic oil.Detail...
Reference: Refer to Troubleshooting, "General Information".
Test Step 1. Perform the following test: Machine Preparation for Troubleshooting
Results:
- OK - Proceed to test step 2.
Test Step 2.
- Allow the temperature of the hydraulic system to cool down. The hydraulic oil temperature should be at the normal operating temperature prior to performing this test.
- Turn the key start switch to the ON position. Put the all wheel drive ECM in the service mode. Clear all of the inactive faults from the all wheel drive ECM.
- Check the all wheel drive ECM for the 600-00 fault code.
Reference: Refer to Troubleshooting, "Using The ECM Display For Troubleshooting".
Expected Result:
The 600-00 fault code is present.
Results:
- No - The initial fault was probably caused by a high temperature in the hydraulic system. Continue to troubleshoot the hydraulic system. Proceed to test step 3.
- Yes - Proceed to test step 4.
Test Step 3. Perform the following test: Valve for Hydraulic Oil Cooler Bypass - Inspect
Results:
- OK - Proceed to test step 5.
- REPAIRED, OK - Stop.
Test Step 4.
- Turn the key start switch to the OFF position. Disconnect the machine harness from the hydraulic oil temperature switch.
- Use a 6V-7070 Digital Multimeter in order to measure the resistance at the machine harness. Measure the resistance from wire 202-BK to the frame ground. The resistance should be less than 2 ohms.
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| Illustration 2 | g00549222 |
HYDRAULI OIL TEMPERATURE SWITCH GRAPHIC | |
Expected Result:
The resistance is less than 2 ohms.
Results:
- No - Proceed to test step 6.
- Yes - Proceed to test step 7.
Test Step 5. Perform the following test: Charge Pressure for Flushing and Cooling Control Valve - Test
Results:
- OK - Proceed to test step 8.
- REPAIRED, OK - Stop.
Test Step 6.
- Repair the faulty harness or replace the faulty harness. Use new Caterpillar parts for replacement.
Expected Result:
The harness has been repaired or the harness has been replaced.
Results:
- Repair Complete - Stop.
Test Step 7.
- Turn the key start switch to the OFF position. When the hydraulic system is cool, the hydraulic oil temperature switch should be closed.
- Use a 6V-7070 Digital Multimeter in order to measure the resistance at the machine harness. Measure the resistance between the two terminals on the hydraulic oil temperature switch. The resistance should be less than 5000 ohms.
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| Illustration 3 | g00549222 |
HYDRAULI OIL TEMPERATURE SWITCH GRAPHIC | |
Expected Result:
The resistance is less than 5000 ohms.
Results:
- No - Proceed to test step 9.
- Yes - Proceed to test step 10.
Test Step 8. Perform the following test: Piston Pump (All Wheel Drive) - Test
Results:
- REPAIRED, OK - Stop.
- OK - Stop.
Test Step 9.
- Replace the hydraulic oil temperature switch. Use new Caterpillar parts for replacement.
Reference: Refer to Troubleshooting, "8W-6342 WIRING GP-SENSOR PIN 5AK1-UP. PART OF 8W-6310 DRIVE AR-ALL WHEEL".Specifications
Reference: Refer to Troubleshooting, "Sensor Wiring (All Wheel Drive)".Schematic...
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| Illustration 4 | g00549222 |
HYDRAULI OIL TEMPERATURE SWITCH GRAPHIC | |
Expected Result:
The hydraulic oil temperature switch has been replaced.
Results:
- Repair Complete - Stop.
Test Step 10.
- Turn the key start switch to the OFF position.
- Disconnect the machine harness from the all wheel drive ECM.
- Use a 6V-7070 Digital Multimeter in order to measure the resistance at the machine harness. Measure the resistance between the contact 12 (wire 482-WH) and contact 2 (wire 202-BK). The resistance should be less than 5000 ohms.
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| Illustration 5 | g00550731 |
ECM | |
Expected Result:
The resistance is less than 5000 ohms.
Results:
- No - Proceed to test step 6.
- Yes - Proceed to test step 11.
Test Step 11.
- Clean the contacts on the machine harness and the harness for the all wheel drive ECM.
- Connect the machine harness to the hydraulic temperature switch. Connect the harness for the all wheel drive ECM to the all wheel drive ECM.
- Turn the key start switch to the ON position. Put the all wheel drive ECM in the service mode. Clear all the inactive faults from the all wheel drive ECM.
- Check the all wheel drive ECM for the 600-00 fault code.
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| Illustration 6 | g00549222 |
HYDRAULI OIL TEMPERATURE SWITCH GRAPHIC | |
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| Illustration 7 | g00550731 |
ECM | |
Reference: Refer to Troubleshooting, "Using The ECM Display For Troubleshooting".
Expected Result:
The 600-00 fault code is present.
Results:
- No - Stop.
- Yes - Proceed to test step 12.
Test Step 12. Perform the following test: All Wheel Drive Electronic Control - Test
Results:
- OK - Stop.
- REPAIRED, OK - Stop.