NOZZLE AS 4W1819 - Caterpillar

System Operation Description:The Electronic Control Module (ECM) must receive an accurate signal that indicates the power output of the generator. When the generator is stopped, the signal must be less than 0.01 VDC. The offset voltage is the voltage level of the signal when the generator is stopped.An offset voltage above 0.01 VDC can be reduced by adding resistance to the circuit.The following steps describe the procedure for adding the correct amount of resistance to the circuit in order to reduce the offset voltage to an acceptable level.Test Step 1. Identify the Configuration of the Wiring
Remove the electrical power from the engine.
Illustration 1 g01076325
Schematic for the wiring between the generator output power sensor and the ECM
Carefully inspect the wiring between the generator output power sensor and the ECM. Refer to Illustration 1. Determine if a potentiometer has been connected to the wiring. Expected Result:A potentiometer is connected to the wiring.Results:
Yes - A potentiometer is connected to the wiring. Proceed to Test Step 3.
No - A potentiometer is not connected to the wiring. Proceed to Test Step 2.Test Step 2. Install a PotentiometerThe potentiometer must have the following characteristics:
5000 Ohms
Linear taper
10 turnsThe wattage rating of the potentiometer is not important. 122-9457 Potentiometer meets these specifications.
Connect the terminal for the wiper to an end terminal. Use a piece of 16 gauge wire in order to make the connection.
Connect an ohmmeter to the end terminals of the potentiometer. Measure the resistance between the end terminals.
Adjust the potentiometer in order to create the minimum resistance across the terminals.
Refer to Illustration 1. Connect the potentiometer to the wiring. Use 16 gauge wire in order to make the connections. You may connect the potentiometer to the positive terminal or to the negative terminal of the generator output power sensor. Expected Result:The potentiometer is connected correctly.Results:
OK - The potentiometer is connected properly. Proceed to Test Step 4.
Not OK - The potentiometer is not connected properly.Repair: Make repairs to the installation, as needed.STOPTest Step 3. Adjust the Potentiometer to the Minimum Value
Disconnect one of the wires that is used to connect the potentiometer to the circuit.
Connect an ohmmeter to the end terminals of the potentiometer.
Adjust the potentiometer in order to create the minimum resistance across the terminals.
Reconnect the wire to the circuit. Expected Result:The potentiometer is set to the minimum value.Results:
OK - The potentiometer is set to the minimum value. Proceed to Test Step 4.
Not OK - The potentiometer is not set to the minimum value.Repair: The potentiometer must be set to the minimum value before you continue with this procedure. Perform this Test Step again. When the potentiometer is set to the minimum value, continue with this procedure.STOPTest Step 4. Adjust the PotentiometerNote: The multimeter must be connected to the P1 connector.
Illustration 2 g01076329
Terminal box
(P1-19) Load signal −
(P1-25) Load signal +
Insert 7X-1710 Multimeter Probes into terminals P1-19 and P1-25. Connect a digital voltmeter to the probes. The polarity of the connections is not important.
Restore the electrical power to the engine. Set the engine control to