This fault is recorded when the current of the reverse pump displacement solenoid valve is greater than normal. This condition is caused by a short to ground. This fault is caused by the following conditions.
- The reverse pump displacement solenoid valve is faulty.
- There is an open in the machine harness.
Reference: Refer to Troubleshooting, "Forward Pump Displacement Solenoid, Reverse Pump Displacement Solenoid".Schematic...
 | |
| Illustration 1 | g00546364 |
MODULATION SWITCH/DISPLACEMENT SOLENOID GRAPHICS | |
System Response:
This fault can be active when the key start switch is turned ON. When this fault is active and the all wheel drive system is ON (AUTOMATIC or MANUAL), the all wheel drive ECM will enter the diagnostic operating mode. The all wheel drive system will shut off and a category three warning will be activated.
Test Step 1. Perform the following test: Machine Preparation for Troubleshooting
Results:
- OK - Proceed to test step 2.
Test Step 2.
- Turn the key start switch to the OFF position. Disconnect the harness connector from the reverse pump displacement solenoid valve.
- Use a 6V-7070 Digital Multimeter in order to measure the resistance at the machine harness. Measure the resistance between contact 1 (wire 797-PU) and contact 2 (wire 912-GY). The resistance should be approximately 30 ohms.
| | |
| Illustration 2 | g00546364 |
MODULATION SWITCH/DISPLACEMENT SOLENOID GRAPHICS | |
Expected Result:
The resistance is approximately 30 ohms.
Results:
- No - Proceed to test step 3.
- Yes - Proceed to test step 4.
Test Step 3.
- Replace the reverse pump displacement solenoid valve. Use a new Caterpillar part for replacement.
Reference: Refer to Troubleshooting, "115-1517 ACTUATOR GP-PUMP PIN 5AK1-UP. PART OF 6E-3471 PUMP GP-PISTON".Specifications
Reference: Refer to Troubleshooting, "Piston Pump (All Wheel Drive)".Schematic...
| | |
| Illustration 3 | g00546364 |
MODULATION SWITCH/DISPLACEMENT SOLENOID GRAPHICS | |
Expected Result:
The reverse pump displacement solenoid valve has been replaced.
Results:
- Repair Complete - Stop.
Test Step 4.
- Connect the harness connector to the reverse pump displacement solenoid valve. Disconnect the harness from the all wheel drive ECM.
- Use a 6V-7070 Digital Multimeter in order to measure the resistance at the harness for the all wheel drive ECM. Check for continuity between contact 10 (wire 797-PU) and contact 39 (wire 912-GY). Measure the resistance between contact 10 (wire 797-PU) and contact 39 (wire 912-GY). The resistance should be approximately 30 ohms.
 | |
| Illustration 4 | g00550731 |
ECM | |
Expected Result:
The resistance is approximately 30 ohms.
Results:
- Yes - Proceed to test step 5.
- No - Proceed to test step 6.
Test Step 5.
- Clean the contacts on the harness for the all wheel drive ECM. Connect the harness 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 391-06 fault code.
Reference: Refer to Troubleshooting, "Using The ECM Display For Troubleshooting".
Expected Result:
The 391-06 fault code is present.
Results:
- Yes - Proceed to test step 7.
- No - The fault does not exist at this time. The initial fault was probably caused by a poor electrical connection at one of the harness connectors. Resume normal machine operation. 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. Perform the following test: All Wheel Drive Electronic Control - Test
Results:
- OK - Stop.
- REPAIRED, OK - Stop.