This diagnostic code is associated with the position sensor for the control of the auxiliary hydraulics. The FMI 01 means that the ECM determined that the signal is below normal operating range.
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| Illustration 1 | g00785407 |
Schematic of the auxiliary control for the auxiliary hydraulics | |
Do NOT start the machine for any of the following Test Steps.
Note: After any repair to the auxiliary hydraulic control, cycle the key start switch five times with at least five seconds between cycles in order to reset the calibrations within the auxiliary hydraulic ECM.
Test Step 1. CHECK THE DUTY CYCLE OF THE AUXILIARY HYDRAULIC CONTROL
- Turn the key start switch to the OFF position.
- Remove the access panel for the work tool control (joystick).
- Locate the connector for the auxiliary hydraulic control beneath the work tool control (joystick).
- Connect the 7X-1710 Multimeter Probe to contact 1 (P996-GN) and contact 2 (P997-BR) on the harness side of the connector.
- Turn the key start switch to the ON position.
Do NOT start the machine.
- Measure the duty cycle of the auxiliary hydraulic control by using the multimeter.
Note: This measurement is performed without actuating the auxiliary hydraulic control.
Expected Result:
The duty cycle should be 50% ± 3%.
Results:
- OK - The duty cycle is 50% ± 3%. Proceed to Test Step 5.
- NOT OK - The duty cycle is NOT 50% ± 3%. Proceed to Test Step 2.
Test Step 2. CHECK THE CONTINUITY OF THE GROUND CIRCUIT OF THE WIRING HARNESS
Check the resistance from contact 2 (wire P997-BR) to frame ground.
Expected Result:
The resistance should be less than 5 ohms.
Results:
- OK - The resistance is less than 5 ohms. Proceed to Test Step 3.
- NOT OK - The resistance is greater than 5 ohms.
Repair: The machine harness has an open in wire P997-BR.Repair the wire harness. After the repair, retest the Tests from Test Step 1 if the diagnostic code is still active.
Stop.
Test Step 3. CHECK THE VOLTAGE OF THE POWER CIRCUIT OF THE WIRING HARNESS
Check the voltage from contact 2 (wire P997-BR) to contact 6 (wire P994-BU).
Expected Result:
The voltage should be approximately 8 volts.
Results:
- OK - The voltage is approximately 8 volts. Proceed to Test Step 4.
- NOT OK - The voltage is NOT approximately 8 volts.
Repair: The machine harness has an open in wire P994-BU.Repair the wire harness. After the repair, retest the Tests from Test Step 1 if the diagnostic code is still active.
Stop.
Test Step 4. CHECK THE DUTY CYCLE OF THE SIGNAL CIRCUIT FROM THE AUXILIARY HYDRAULIC CONTROL
- Turn the key start switch to the OFF position.
- Remove the pin (wire P996-GN) from contact 1 of the machine side of the connector.
- Connect the 7X-1710 Multimeter Probe to contact 2 (P997-BR) and contact 1 (P996-GN) on the joystick's side of the connector.
- Turn the key start switch to the ON position.
Do NOT start the machine.
- By using the multimeter, measure the duty cycle of the auxiliary hydraulic control.
Note: This measurement is performed without actuating the auxiliary hydraulic control.
Expected Result:
The duty cycle should be 50% ± 3%.
Results:
- OK - The duty cycle is 50% ± 3%.
Repair: There is a short in the machine harness between contact 1 (P996-GN) of the connector and contact 53 of the auxiliary hydraulic ECM. Repair the wire harness. After the repair, retest the Tests from Test Step 1 if the diagnostic code is still active.
Stop.
- NOT OK - The duty cycle is NOT 50% ± 3%.
Repair: Contact the Technical Communicator for your Caterpillar dealership before replacing the work tool control (joystick).
Stop.
Test Step 5. ACTUATE THE AUXILIARY HYDRAULIC CONTROL AND CHECK THE DUTY CYCLE
- The key start switch remains in the ON position.
- The multimeter probes remain in contact 1 and contact 2.
- Actuate the right side of the auxiliary hydraulic control and measure the duty cycle.
- Actuate the left side of the auxiliary hydraulic control and measure the duty cycle.
Expected Result:
The duty cycle should vary from approximately 50% to at least 25% in the right direction and the duty cycle should vary from approximately 50% to at least 75% in the left direction.
Results:
- OK - The duty cycles are within the range of the Expected Results. Proceed to Test Step 6.
- NOT OK - The duty cycles are NOT within the range of the Expected Results.
Repair: The auxiliary control has failed. Replace the control handle.
Stop.
Test Step 6. CHECK THE SIGNAL OF THE AUXILIARY HYDRAULIC CONTROL AT THE ECM
- Turn the key start switch to the OFF position.
- Remove the access panel for the auxiliary hydraulic ECM.
- Locate the machine harness connector for the auxiliary hydraulic ECM.
- The 7X-1710 Multimeter Probe remains in contact 2 (P997-BR) on the harness side of the connector.
- Connect the other 7X-1710 Multimeter Probe to contact 53 (P996-GN) to the machine harness connector at the ECM.
- Turn the key start switch to the ON position.
Do NOT start the machine.
- Use the multimeter and measure the duty cycle of the auxiliary hydraulic control.
Expected Result:
The duty cycle should be 50% ± 3%.
Results:
- OK - The duty cycle is 50% ± 3%.
Repair: Check the machine harness connectors for the proper connection. Cycle the key start switch and check for an active diagnostic code. If the diagnostic code is still active, contact the Technical Communicator for your Caterpillar dealership.
Stop.
- NOT OK - The duty cycle is NOT 50% ± 3%.
Repair: The machine harness has an open in wire P996-GN between contact 53 of the ECM and contact 1 of the connector for the auxiliary hydraulic control.Repair the wire harness and retest this Test Step. After the repair, verify that the diagnostic code is no longer active. If the diagnostic code is still active, contact the Technical Communicator for your Caterpillar dealership.
Stop.