0174450 JOHNSON FUEL TANK ASSY.

Use this procedure to check if the mode selection switch operates correctly.The mode selection switch inputs provide the operator with the ability to select a maximum of four different modes of operation. Different modes of operation can be used giving the operator a means to select the most efficient method of completing the required work.Each mode has a single fuel limit map, a rated speed, and a matched fuel delivery. Each mode also has a specific droop value for throttle 1 and throttle 2.
Table 2
Mode Number Switch 2 Switch 1 Enabled
1 Open Open Y/N
2 Open Closed Y/N
3 Closed Open Y/N
4 Closed Closed Y/N If a fault occurs in the circuit for either of the switches, the mode of operation will be different to the mode that was selected. If the mode of operation is not enabled on the application, a 2882-2 or 1743-2 diagnostic code will become active.During the following procedure, refer to the electrical schematic for the application.Complete the procedure in the order in which the steps are listed.
Table 3
Troubleshooting Test Steps Values Results
1. Inspect Electrical Connectors and Wiring
A. Turn the keyswitch OFF.
B. Thoroughly inspect the P1 connector. Thoroughly inspect the mode switch connectors, plugs, and interconnections on the harness. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
C. Perform a 45 N (10 lb) pull test on each of the wires in the P1 connector that are associated with the mode selector switches.
D. Check the screw for the ECM connector for the correct torque of 6 N m (53 lb in).
E. Check the harness for abrasions and for pinch points from the mode section switches to the ECM.
Loose connection or damaged wire
Result: There is a fault in a connector or the wiring.
Repair: Repair any faulty connectors or replace the wiring harness. Ensure that all the seals are properly in place and ensure that the connectors are correctly coupled.
Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault.
Result: All connectors, pins, and sockets are correctly coupled and/or inserted. The harness is free of corrosion, abrasion, and pinch points.
Proceed to Test Step 2.
2. Check the Status of the Mode Selection Switch
A. Turn the keyswitch to the OFF position.
B. Connect the electronic service tool to the diagnostic connector.
C. Turn the keyswitch to the ON position.
D. Monitor the status screen on the electronic service tool. Cycle the mode switch to the ON position and to the OFF position.
Switch status changes
Result: The switch status changes on the electronic service tool as the mode switches are cycled.
Use the electronic service tool to clear all logged diagnostic codes. Return the engine to service.
Result: The switch status does not change as the mode switches are cycled.
Proceed to Test Step 3.
3. Insert a Jumper at the Suspect Mode Switch
A. Turn the keyswitch to the OFF position.
B. Disconnect the connector for the suspect mode selection switch.
C. Fabricate a jumper wire and install the jumper wire across the two contacts of the suspect switch.
D. Turn the keyswitch to the ON position. Monitor the status screen on the electronic service tool. Connect the jumper wire and then disconnect the jumper wire.
E. Turn the keyswitch to the OFF position. Remove the jumper wire.
Switch status "CLOSED" with jumper installed
Result: When the jumper wire is connected, the switch is in the CLOSED position.
Repair: Replace the suspect mode selection switch.
Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault.
Result: When the jumper wire is connected, the switch is in the OPEN position
Proceed to Test Step 4.
4. Measure the Voltage at the Switch
A. Turn the keyswitch to the OFF position.
B. Disconnect the connector for the mode selection switches.
C. Turn the keyswitch to the ON position.
D. Use the electronic service tool to turn both of the mode switches to the ON position.
E. Measure the voltage from the input of each mode switch to a suitable ground.
At least 10 VDC for a 12 V system
At least 22 VDC for a 24 V system
Result: One of the measured voltages is not within the expected range - The fault is in the wiring between the suspect mode switch and the ECM.
Repair: Repair the faulty wiring or replace the faulty wiring.
Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault.
Result: The measured voltages are within the expected range.
Proceed to Test Step 5.
5. Check the Wiring for an Open Circuit
A. Turn the keyswitch to the OFF position.
B. Disconnect the connector for the mode switches.
C. Disconnect the P1 connector from the ECM.
D. Measure the resistance between the "Mode Switch 1" terminal on the P1 connector and the applicable terminal on the mode switch harness connector.
E. Measure the resistance between the "Mode Switch 2" terminal on the P1 connector and the applicable terminal on the mode switch harness connector.
Less than 2.0 Ohms
Result: One of the measured resistances is greater than 2.0 Ohms - The fault is in the wiring between the suspect mode switch and the ECM.
Repair: Repair the faulty wiring or replace the faulty wiring.
Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault.
Result: All measured resistances are less than 2.0 Ohms.
Proceed to Test Step 6.
6. Check the Wiring for a Short Circuit
A. Turn the keyswitch to the OFF position.
B. Disconnect the connector for the mode switches.
C. Disconnect the P1 connector from the ECM.
D. Measure the resistance between the "Mode Switch 1" terminal on the P1 connector and all other terminals on the P1 connector.
E. Measure the resistance between the "Mode Switch 2" terminal on the P1 connector and all other terminals on the P1 connector.
Greater than 100 Ohms
Result: One of the measured resistances is less