0435576 JOHNSON PISTON, Stbd., Standard

Illustration 1 g01222823
Schematic for the throttle switch
Test Step 1. Inspect Electrical Connectors and Wiring
Remove the electrical power from the ECM.
Illustration 2 g01186024
Location of the J1/P1 ECM connector (typical left side engine view)
Thoroughly inspect the J1/P1 ECM connector. Refer to diagnostic functional tests Troubleshooting, "Electrical Connectors - Inspect" for details.
Illustration 3 g01250533
Terminal locations at the P1 ECM connector
(P1-22) Throttle input #1 (low)
(P1-23) Throttle input #2 (low par)
(P1-40) Throttle input #3 (high)
(P1-41) Throttle input #4 (high par)
Illustration 4 g01250541
Terminal locations at the throttle switch
(Terminal 1) Throttle input #1 (low)
(Terminal 2) Return
(Terminal 3) Throttle input #4 (high par)
(Terminal 4) Throttle input #2 (low par)
(Terminal 5) Return
(Terminal 6) Throttle input #3 (high)
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector and at the connector for the throttle switch.
Check the allen head screw for each of the ECM connectors for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
Check the harness and wiring for corrosion, for abrasion, and for pinch points from the throttle switch 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 connectors appear to be 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 the Status of the Throttle Inputs
Connect the Cat ET to the service tool connector.
Restore the electrical power to the ECM. Note: Wait at least 30 seconds in order for the diagnostic codes to become active.
Observe the status of the throttle inputs on Cat ET while you operate the throttle switch in each position.
Table 1
Throttle Input Neutral High "Rabbit" Low "Tortoise"
"#1 (Low)" Off Off On
"#2 (Low Par)" On Off On
"#3 (High)" Off On Off
"#4 (High Par)" On On Off Expected Result:The status of the throttle switch corresponds with the table above.Results:
OK - The status of the throttle switch is correct.Repair: The throttle switch is functioning properly at this time. There may be an intermittent electrical problem in the wiring harness or in a connector. If an intermittent electrical problem is suspected, refer to Troubleshooting, "Electrical Connectors - Inspect" for troubleshooting information.STOP
Not OK - One or more of the inputs is incorrect. There is a problem in the circuit for the throttle switch. Proceed to Test Step 3.Test Step 3. Check the Harness between the Throttle Switch and the ECM
Remove the electrical power from the ECM.
Fabricate a jumper wire that is long enough to create a short circuit across the connector for the throttle switch. Crimp spade terminals to each end of the jumper wire.
Disconnect the wires for the suspect throttle inputs from the throttle switch.
Restore the electrical power to the ECM.
Check the status of the suspect throttle inputs on Cat ET. Refer to Table 1.
Use the jumper wire to short the wires for the suspect throttle inputs to the return wire at the switch. Note: Wait at least 30 seconds in order for the diagnostic codes to become active.
Monitor the status of the suspect throttle input(s) on Cat ET.
Remove the jumper wire. Reconnect all wires to the original configuration. Expected Result:The status of the suspect throttle inputs change when the jumper wire is connected.Results:
OK - The harness and the ECM are OK.Repair: There is a problem with the throttle switch. Replace the switch. Verify that the repair eliminates the problem.STOP
Not OK - The status of the suspect throttle inputs do not change when the jumper wire is installed. Verify that the return circuit for the throttle switch is continuous to chassis ground. Ensure that the return circuit has a good connection to the chassis ground. Proceed to Test Step 4.Test Step 4. Check the Operation of the ECM
Remove the electrical power from the ECM.
Disconnect the J1/P1 ECM connector.
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