MARINE GEAR GROUP 3N4552 - Caterpillar

Illustration 1 g00634052
Schematic of the Modulating Valve for Speed 1 (Number 5)
This diagnostic code is for the Modulating Valve for Speed 1 (Number 5).See Systems Operation, "Solenoid Valves" for help with the identification of the locations of the solenoids.This diagnostic code is recorded when the current of the solenoid circuit is above normal. Note: Ensure that CID 0695 FMI 06 for the solenoid is on hold and that the diagnostic code indicator shows "SERV CODE". Test Step 1. CHECK THE SOLENOID AND THE INTERNAL HARNESS OF THE TRANSMISSION.
Turn the key start switch to the ON position.
Ensure that the diagnostic code for the solenoid is on hold.
Observe the status of the diagnostic code indicator.
At the transmission case, disconnect the machine harness from the internal harness for the transmission. Expected Result:"SERV CODE" is NOT showing when the internal harness for the transmission is disconnected. Results:
YES - "SERV CODE" is NOT showing when the internal harness for the transmission is disconnected. The circuit is correct. The solenoid or the internal harness for the transmission has failed. Proceed to Test Step 2.
NO - "SERV CODE" is showing when the internal harness for the transmission is disconnected. The diagnostic code remains. Proceed to Test Step 3.Test Step 2. CHECK THE RESISTANCE OF THE SOLENOID.
Within the transmission case, disconnect the internal harness for the transmission from the solenoid that is suspected.
At the solenoid, measure the resistance between the two contacts of the connector for the solenoid. Expected Result:The resistance should be greater than 5 ohms.Results:
OK - The resistance is greater than 5 ohms.Repair: The resistance of the solenoid is correct. The internal harness for the transmission is failed. In the internal harness for the transmission, the wire for the signal to the solenoid is shorted to the return circuit for the solenoid (wire 975-WH(White)) or to the frame ground. Repair the internal harness for the transmission or replace the internal harness for the transmission.STOP
NOT OK - The resistance is not greater than 5 ohms.Repair: The solenoid has failed. Replace the solenoid.STOPTest Step 3. CHECK THE SIGNAL CIRCUIT FOR THE SOLENOID FOR A SHORT TO GROUND.
At the transmission case, the machine harness remains disconnected from the internal harness for the transmission. Turn the key start switch to the OFF position.
Disconnect the machine harness from the solenoid.
Disconnect the machine harness connectors J1 and J2 from the ECM.
At machine harness connector J1 or J2, measure the resistance from the solenoid signal contact to all possible sources of ground. The possible ground sources are contact J1-2, contact J1-5, contact J1-7, contact J1-15, contact J1-16, contact J2-3 and frame ground. Expected Result:Each resistance should be greater than 5000 ohms.Results:
OK - Each resistance is greater than 5000 ohms. The machine harness is correct. Proceed to Test Step 4.
NOT OK - Each resistance is not greater than 5000 ohms.Repair: There is a short in the machine harness. The short is between the wire for the signal to the solenoid and the circuit that has a low resistance measurement.