SFWR GP-A5000 2254132 - Caterpillar

Diagnostic Codes
Table 1
Transmission ECM
DTC Code Description System Response
793-4 Primary Steering Pressure Switch : Voltage Below Normal Steering system will be unable to diagnose a loss of primary steering pressure Possible Causes and Schematics
The primary steering pressure switch is connected to two inputs of the ECM. One contact is open and the other contact is grounded during proper operation. A change in condition would indicate a lack of steering fluid to operate the machine.Possible Causes for an FMI 4 Diagnostic Code are:
A short to ground.
The switch has failed.
The ECM has failed. A failure of the ECM is unlikely.The ECM has determined that both contacts are grounded.
Illustration 1 g06271267
Schematic of the Primary Steering pressure switch circuit associated with the Transmission ECM.
Table 2
Primary Steering Pressure Switch
Switch Position 417-GY(Grey)Circuit
N/O
J2-37 484-YL(Yellow)Circuit
N/C
J2-38
Low Pressure Open Closed
High Pressure Closed Open Troubleshooting Procedure
Before performing this procedure, inspect the harness connectors that are involved in the circuit. Poor connections can often be the cause of a problem in an electrical circuit. Verify that all connections in the circuit are clean, secure and in good condition. If a problem with a connection is found, correct the problem and verify that this diagnostic code is active before performing this procedure.
Table 3
Troubleshooting Test Steps Values Results
Begin Process For FMI 4 Troubleshooting HERE
1. Check The Switch
A. Turn the key start switch and the disconnect switch to the OFF position.
B. Disconnect the machine harness connector from the switch.
C. Turn the key start switch and the disconnect switch to the ON position.
D. At the machine harness connector for the switch, measure resistance between the ground contact and frame ground.
The DTC 793 - 4 has been replaced by DTC 793 - 3. OK - The DTC 793 - 4 has been replaced by DTC 793 - 3. The machine harness and the ECM are correct.
Proceed to Test Step 3.
NOT OK- The DTC 793 - 4 is still active.
Proceed to Test Step 2.
2. Check The Harness
A. Turn the key start switch and the disconnect switch to the OFF position.
B. The machine harness connector