0175977 JOHNSON MANIFOLD ASSY.

Illustration 1 g01253310
Schematic
Table 1 shows continuity between the contacts of the throttle position switch in each position.
Table 1
Throttle Position Switch
Position Contacts
1 COM, S1
2 COM, S1, S2
3 COM, S2
4 COM, S2, S3
5 COM, S1, S2, S3
6 COM, S1, S3
7 COM, S3
8 COM, S3, S4
9 COM, S1, S3, S4
10 COM, S1, S2, S3, S4
Illustration 2 g01120703
P1 ECM connector
(P1-5) Digital return
(P1-22) Throttle backup switch
(P1-23) Throttle backup switch
(P1-66) Throttle command Test Step 1. Inspect Electrical Connectors and Wiring
Turn the keyswitch to the OFF position.
Thoroughly inspect the J1/P1 ECM connector and the J2/P2 ECM connector. Inspect all of the connectors that are associated with the circuit.
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that is associated with the active diagnostic code.
Check the ECM connector (allen head screw) for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Check the harness and wiring for abrasions and for pinch points from the sensors back to the ECM. Expected Result:All connectors, pins, and sockets are completely coupled and/or inserted. The harness and wiring are free of corrosion, of abrasion, and of pinch points.Results:
OK - The harness and wiring are OK. Proceed to Test Step 2.
Not OK - There is a problem in the connectors and/or wiring.Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled.Verify that the repair eliminates the problem.STOPTest Step 2. Check for Active Diagnostic Codes
Connect Caterpillar Electronic Technician (ET) to the service tool connector.
Turn the keyswitch to the ON position.
Monitor the active diagnostic code screen on Cat ET. Check and record any active diagnostic codes. Note: Wait at least 30 seconds in order for the diagnostic codes to become active.Expected Result:No diagnostic codes are active.Results:
OK - No diagnostic codes are active.Repair: The problem may have been related to a faulty connection in the harness. Carefully reinspect the connectors and wiring. Refer to Troubleshooting, "Electrical Connectors - Inspect".STOP
Not OK - A 91-08 diagnostic code is active at this time. Proceed to Test Step 3.Test Step 3. Check the Throttle Signal on Cat ET
Turn the keyswitch to the ON position.
Observe the status of "Throttle" on Cat ET.
Turn the throttle switch and observe the status of "Throttle" on Cat ET.
Turn the keyswitch to the OFF position. Expected Result:The throttle varies from 0 to 100 percent.Results:
OK - The throttle varies from 0 to 100 percent. The throttle and circuitry are operating correctly.Repair: If the problem is intermittent, refer to Troubleshooting, "Electrical Connectors - Inspect".STOP
Not OK - The throttle signal did not vary from 0 to 100 percent. Proceed to Test Step 4.Test Step 4. Check the Throttle Command at the Engine and Hydraulic Pump Controller
Remove the wire F889-WH(White) from terminal 44 of the engine and hydraulic pump controller.
Turn the keyswitch to the ON position.
Use a multimeter to monitor the percent duty cycle of the throttle command at terminal 44 of the engine and hydraulic pump controller. Adjust the throttle switch from the low idle position to the high idle position.
Turn the keyswitch to the OFF position. Expected Result:At low idle, the duty cycle is between 5 percent and 10 percent. At high idle, the duty cycle is between 90 percent and 95 percent.Results:
OK - The throttle command is correct. Proceed to Test Step 5.
Not OK - The throttle command is not correct. There may be a problem with the throttle switch or the engine and hydraulic pump controller.Repair: If a problem is suspected with the throttle position switch, refer to Table 1 for information on continuity between the switch contacts when the switch is in each position.If a problem is suspected with the engine and hydraulic pump controller, refer to the System Operation manual and the Testing and Adjusting manual for the machine.STOPTest Step 5. Check the Throttle Command at the ECM
Turn the keyswitch to the OFF position.
Fabricate a jumper wire that can be used to replace the signal wire in the ECM connector for the throttle signal. Crimp a connector socket to one end of the jumper wire.
Disconnect the J1/P1 ECM connector.
Remove the wire F889-WH(White) from ECM connector P1-66. Install the jumper wire into the terminal location for the throttle signal at the ECM connector.
Reconnect the ECM connectors.
Turn the keyswitch to the ON position.
Use a multimeter to monitor the percent duty cycle of the throttle command between ECM connector P1-66 (throttle command) and engine ground. Adjust the throttle switch from the low idle position to the high idle position.
Turn the keyswitch to the OFF position.
Replace all wires to the original configuration. Expected Result:At low idle, the duty cycle is between 5 percent and 10 percent. At high idle, the duty cycle is between 90 percent and 95 percent.Results:
OK - The throttle command is correct. The ECM is not processing the command properly. Verify that the ECM is receiving the correct battery voltage. If the ECM is receiving the correct battery voltage, replace the ECM.Repair: Refer to Troubleshooting, "Replacing the ECM" before replacing the ECM.STOP
Not OK - The throttle command is not correct.Repair: There is a problem in the harness or connectors between the engine and hydraulic pump control and the ECM. Repair the circuit. Verify that the repair eliminates the problem.STOP