Auxiliary Hydraulic Does Not Function in Either Direction SMCS - 5005-038-EA Top of Form System Operation Description: Press the switch (A1) in order to enable the auxiliary hydraulics (A1). Press the switch (A2) in order to enable the auxiliary hydraulics (A2). 
|
| Illustration 1 | g00778870 | Schematic of the circuit for the auxiliary hydraulics (A1 and A2) The schematic is associated with the following machines: 216 (4NZ1-2499) 226 (5FZ1-5199) 228 (6BZ1-699) 236 (4YZ1-3999) 246 (5SZ1-3999) 248 (6LZ1-999) |
| 
|
| Illustration 2 | g00785974 | Schematic of the circuit for the auxiliary hydraulics (A1 and A2) The schematic is associated with the following machines: 216 (4NZ2500-UP) 226 (5FZ5200-UP) 228 (6BZ700-UP) 236 (4YZ4000-UP) 246 (5SZ4000-UP) 248 (6LZ1000-UP) 252 (FDG1-UP) 262 (CED1-UP) 267 (CMP1-UP) 277 (CNC1-UP) 287 (CNY1-UP) |
Note: Check for any diagnostic codes that are displayed on the Caterpillar ET before performing the following Test Steps. Test Step 1. CHECK FOR PROPER OPERATION FOR A1 - Enable the machine.
- Press the switch (A1) .
Expected Result: The auxiliary hydraulics (A1) should be active. Results: - OK - The auxiliary hydraulics (A1) are active. Proceed to Test Step 2.
- NOT OK - The auxiliary hydraulics (A1) are not active. Proceed to Test Step 6.
Test Step 2. CHECK FOR PROPER OPERATION - Enable the machine.
- Push down on either the A1 switch or the A2 switch.
Expected Result: The auxiliary hydraulics (A1 or A2) should be active. Results: - OK - The auxiliary hydraulics (A1 or A2) are active.
Repair: There is no problem at this time. Stop. - NOT OK - The auxiliary hydraulics (A1 or A2) are not active. Proceed to Test Step 3.
Test Step 3. CHECK THE STATUS OF THE SWITCH - Press and release the auxiliary hydraulic switch (A1).
- Observe the status on the Caterpillar ET.
- Press and release the auxiliary hydraulic switch (A2).
- Observe the status on the Caterpillar ET.
Expected Result: The switch status should have changed from the "CLOSED" status to the "OPEN" status. Results: - OK - The switch status changed from the "CLOSED" status to the "OPEN" status. Proceed to Test Step 4.
- NOT OK - The switch status did not change from the "CLOSED" status to the "OPEN" status on both A1 and A2. Proceed to Test Step 5.
- NOT OK - The status of either A1 or A2 did not change from the "CLOSED" status to the "OPEN" status.
Repair: See Troubleshooting, "Auxiliary Hydraulics Does Not Function In One Direction". Stop. Test Step 4. CHECK THE OUTPUT OF THE ECM - Remove the floorplate in order to get to the ECM.
- Locate the wires P978-GN and L998-OR coming out of the ECM.
- Enable the machine.
- Push down on the A1 switch.
- Measure the voltage from wire P978-GN to wire L998-OR. Measure the voltage on the back side of a connector or by penetrating the wire insulation.
Note: Two people will be needed to perform the measurements. One person will need to occupy the seat in order to keep the machine enabled. The other person will take the measurement. Expected Result: The voltage should be greater than 10 VDC. Results: - OK - The voltage is greater than 10 VDC.
Repair: The problem does not appear to be electrical. Stop. - NOT OK - The voltage is less than 10 VDC.
Repair: The ECM is very unlikely to have failed. Reconnect all connections and visually inspect the wire harness. Verify that the values that are present on the machine configuration screen match the machine's options. Verify that the values that are present on the machine configuration screen are installed correctly. Verify that the diagnostic code still exists. If the diagnostic code still exists perform the test steps again.Replace the ECM, if the cause of the diagnostic code was not found after the second attempt. See Testing and Adjusting, "Electronic Control Module (ECM) - Replace". Stop. Test Step 5. CHECK THE SWITCH CIRCUIT - Remove the floorplate in order to get to the ECM.
- Remove the wire harness from the ECM.
- Press the switch (A1).
- Measure the resistance from contact 52 to contact 53 of the wire harness connector.
- Press the switch (A2).
- Measure the resistance from contact 52 to contact 62 of the wire harness connector.
Expected Result: The resistances should be less than 5 Ohms on both of the readings. Results: - OK - The resistances were less than 5 Ohms.
Repair: The ECM is very unlikely to have failed. Reconnect all connections and visually inspect the wire harness. Verify that the values that are present on the machine configuration screen match the machine's options. Verify that the values that are present on the machine configuration screen are installed correctly. Verify that the diagnostic code still exists. If the diagnostic code still exists perform the test steps again.Replace the ECM, if the cause of the diagnostic code was not found after the second attempt. See Testing and Adjusting, "Electronic Control Module (ECM) - Replace". Stop. - NOT OK - The resistances were greater than 5 Ohms.
Repair: The circuit is open in the wire harness and/or the connector. Repair the wire harness and/or the connector or replace the wire harness and/or the connector. Stop. Test Step 6. CHECK THE STATUS OF THE AUXILIARY CONTROL - Actuate the auxiliary control.
- Observe the status for the auxiliary hydraulics on the Caterpillar ET.
Expected Result: The amperes for the auxiliary hydraulic status should be displaying values that are greater than "0.00". Results: - OK - The ampere for the auxiliary hydraulic status is displaying a value that is greater than "0.00".
Repair: If there is no diagnostic codes that are present, the problem does not appear to be an electrical problem. Stop. - NOT OK - The ampere for the auxiliary hydraulic status is displaying "0.00".
Repair: The ECM is very unlikely to have failed. Reconnect all connections and visually inspect the wire harness. Verify that the values that are present on the machine configuration screen match the machine's options. Verify that the values that are present on the machine configuration screen are installed correctly. Verify that the diagnostic code still exists. If the diagnostic code still exists perform the test steps again.Replace the ECM, if the cause of the diagnostic code was not found after the second attempt. See Testing and Adjusting, "Electronic Control Module (ECM) - Replace". Stop. |