Water Delivery System and 777F WTR, 777G WTR and 785D WTR OEM Off-Highway Trucks Caterpillar

Hydraulic System Oil Temperature Is High

Usage:

785D DMC

This diagnostic code is recorded when the WDS ECM reads the signal of the WDS hydraulic oil temperature sensor as higher than 93° C (199° F).

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Illustration 1	g03610786

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Illustration 2	g03642905

Note: This error code can occur when the ambient temperature exceeds 43° C (109° F) and when the demand on the WDS system for water flow is high (Heavy Coverage). If this error code persists in high ambient temperature conditions, try reducing the demand on the WDS system.

Note: The high temperature and the high hydraulic pressure diagnostic codes may both be displayed. In this case follow the troubleshooting procedure listed for High Hydraulic Pressure Diagnostic Code before diagnosing the High Hydraulic Oil Temperature Error Code.

The possible causes of high hydraulic oil temperature are listed below:

Clogged cooler fins
Failed fan motor fuse
Failed cooler fan motor
Failed cooler bypass valve
Failed water pump
Failed hydraulic motor
Failed hydraulic pump

Check WDS Cooler Fan Motor
1. Park the machine. Turn key start switch to the OFF position.
2. Remove the cooler guard.
3. Ensure that there is no debris build-up on the cooler fins.
4. Manually rotate the fan to ensure that the fan rotates freely.
  Expected Results: There is no debris on cooler fins. The cooling fan rotates freely.
  Results:
  OK - The cooler fins are clean and the cooling fan rotates freely. Proceed to Step 2.
  Not OK - There is debris on cooler fins.
  Repair: Clean the cooler fins. Check the error code.
  STOP.
  Not OK - The fan shaft does not rotate freely. Failed fan motor.
  Repair: Change the fan motor. Check the error code.
  STOP.
Check WDS Cooler Fan Motor Fuse
1. Park the machine.
2. Cycle the key start switch to the OFF position and then to the ON position.
3. Observe the WDS cooler fan when the key start is turned to ON position.
  Expected Result: The cooler fan motor runs for 30 seconds when the start key is turned to ON position.
  Results:
  OK - The cooler fan runs for 30 seconds. Proceed to Step 5.
  Not OK - The cooler fan does not run. Proceed to Step 3 to
Check WDS Cooler Fan Motor Fuse
1. With the machine still parked, turn the key start switch to the OFF position.
2. Locate the fan motor fuse inside the machine cab.
3. Check the fan motor fuse.
  Expected Result: The fuse is not faulty.
  Results:
  OK - The fuse is not faulty. Proceed to Step 4.
  Not OK - The fuse is blown.
  Repair: Change the fuse (15 Amp.). Return to Step 2.
Check WDS Cooler Fan Motor Chassis Harness and Relay
1. With the machine still parked, turn the key start switch to the OFF position.
2. Check the WDS cooler fan motor relay located inside the machine cab.
3. Check the wiring continuity of wires A124 and 229 used for the fan motor.
  Expected Result: The relay is not faulty and wire continuity is not faulty.
  Results:
  Not OK - The relay has failed.
  Repair: Replace the relay. Check the diagnostic code.
  STOP.
  Not OK - The harness has failed.
  Repair: Repair or replace the harness. Check the diagnostic code.
  STOP.
Check WDS Cooler Fan Motor Speed
1. With the machine still parked, turn the key start switch to the OFF position.
2. Add reflective tape to the cooler fan to measure speed.
3. Turn the key start switch to the ON position and start the engine.
4. Measure the fan speed during initial startup. Use a 368-9910 Multi-Tool Gp.
  Expected Result: The fan speed is approximately 1850 rpm.
  Results:
  OK - The fan speed is within range (1850 rpm +/- 50 rpm). Proceed to Step 6.
  Not OK - The fan speed is less than 1800 rpm. Possibly failing motor bearing.
  Repair: Replace the fan motor. Repeat Step 5.
  STOP.
Check WDS Cooler Bypass Valve
1. With the machine still parked, turn the key start switch to the OFF position.
2. Connect a flow meter to the cooler outlet line. Use a 4C-9910 Portable Hydraulic Tester with a 4C-9911 Flow Meter Gp.
3. Turn the key start switch to the ON position. Start engine and let the engine idle.
4. Select the "cannon" mode on the WDS keypad.
5. Position the water cannon to a spray into a remote location.
6. Turn on the WDS water pump.
7. Ensure that the WDS oil temperature is above 70° C (158° F).
8. Measure the oil flow rate
  Expected Result: The hydraulic oil flow rate at low idle is approximately 7 gpm.
  Results:
  OK - The hydraulic oil flow rate is approximately 7 gpm.
  Note: This error code can occur when the ambient temperature exceeds 43° C (109° F) and when the demand on the WDS system for water flow is high (Heavy Coverage). In the case that the high hydraulic oil temperature error code persists in high ambient conditions, try reducing the demand on the WDS system.
  Not OK - The flow rate is less than 5 gpm. Possibly failed bypass valve.
  Repair: Replace or repair the bypass valve. Repeat Step 6.
  STOP.