SLEEVE 1227678 - Caterpillar

Illustration 1 g02727645
Connections of the Primary Steering Valve Spool Displacement Signal Line
This diagnostic code is associated with the Primary Steering Valve Spool Displacement Signal Line. The position sensor is located in the control module of the steering valve.The FMI 04 diagnostic code is activated when the ECM detects a below normal voltage of the signal circuit.The spool position sensor for the steering valve control module supplies an analog signal to the ECM. The signal indicates the position of the valve spool. The signal voltage varies from 0.1 VDC to 4.9 VDC. When no steering is requested, desired steering angle is zero and the spool is centered, a signal voltage of approximately 2.5 0.3 VDC will be supplied to the ECM. The following conditions could cause this diagnostic code to be activated:
The signal circuit is shorted to a ground source.
The sensor has failed.
The ECM has failed. An ECM failure is unlikely.Before performing this procedure, inspect the harness connectors that are involved in the circuit. Check the connector that passes the wires through the bulkhead at the front of the cab. Poor connections can often be the cause of a problem in an electrical circuit. Inspect the connections for the following:
Connections are clean.
Connections are secure.
Connections are 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.Note: The following test procedure may create other diagnostic codes. Clear the diagnostic codes when the problem has been corrected.Test Step 1. CHECK THE SENSOR
Turn the key start switch and disconnect switch to the ON position.
Disconnect the machine harness connector from the spool valve position sensor.
Observe the status of the active CID 2203 FMI 04 diagnostic code. Expected Result:The status of the CID 2203 FMI 04 diagnostic code did not change when the connector of the sensor was disconnected. A CID 2203 FMI 03 diagnostic code has not been activated by the Steering ECM. The CID 2203 FMI 04 diagnostic code remains active when the connector of the sensor is disconnected.Results:
OK - The CID 2203 FMI 04 diagnostic code remains active when the connector of the sensor is disconnected. The sensor is not causing the problem. Proceed to Test Step 2.
NOT OK - The CID 2203 FMI 04 diagnostic code is no longer active when the connector of the sensor is disconnected. A CID 2203 FMI 03 diagnostic code has been activated by the ECM when the connector of the sensor is disconnected. The machine harness and the ECM are operating correctly.Repair: The sensor is causing the problem. There is an internal short to ground in the sensor. Replace the sensor. After replacing the sensor, verify that the operation is correct before operating the machine.STOPTest Step 2. CHECK THE SIGNAL CIRCUIT FOR A SHORT
Turn the key start switch and disconnect switch to the OFF position.
Disconnect the machine harness connector from the position sensor.
Disconnect the machine harness connectors J1 and J2 from the Steering ECM.
At the J1 machine harness connector for