5031800 JOHNSON *SCREW

Illustration 1 g00646460
Schematic for transmission neutral switch
Test Step 1. Inspect Electrical Connectors and Wiring
Illustration 2 g01151850
Pin locations on ECM connector
(P1-62) Input 12 (transmission neutral switch)
Thoroughly inspect ECM vehicle harness connector J1/P1, the firewall bulkhead connector and the terminals for the following switches in the connectors:
Neutral switch (P1-62)Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the switches. Refer to Illustration 2.
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 abrasion and pinch points from the sensor to the ECM. Expected Result:All connectors, pins and sockets are completely coupled and/or inserted and the harness and wiring are free of corrosion, of abrasion or of pinch points.Results:
OK - Proceed to Test Step 2.
Not OK - 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 Neutral Switch Status on Caterpillar Electronic Technician (ET)
Table 1
Status of the Neutral Switch
Switch Position Switch Status Circuit
The transmission is in Neutral. ON Closed
The transmission is in Gear. OFF Open
Connect Cat ET to the cab data link connector.
Access the status screen on Cat ET.
Turn the ignition key switch to the ON position.
Shift the transmission into the Neutral position while the status of the neutral switch is being observed. Also, shift out of Neutral while the status of the neutral switch is being observed. Note: If the status indicates "Not Installed", check the programming of the "Transmission Style" Parameter. The "Transmission Style" must be programmed to "Automatic Option 3" or "Automatic Option 4".Expected Result:The switch status changes per the information in Table 1.Results:
Yes - The switch is operating normally.STOP
No - The ECM is not reading the switch status change. Proceed to Test Step 3.Test Step 3. Check the Switch Circuit for the ECM
Table 2
Status of the Neutral Switch Input
Condition of Switch Circuit Switch Status Circuit
Terminal 62 is open. OFF Open
Terminal 62 connected to +battery. ON Closed
Turn the ignition key switch to the OFF/RESET position.
Fabricate a jumper wire 100 mm (4 inch) long. Crimp a Deutsch pin to both ends of the wires.
Disconnect vehicle harness connector P1 from the ECM.
Connect a breakout T to ECM connector J1 and connect P1 to the breakout T.
Install the jumper into terminal 62 (neutral switch) of the breakout T. Connect the other end of the jumper to terminal 52 (unswitched +Battery) of the breakout T.
Turn the ignition key switch to the ON position.
Verify that Cat ET is connected to the cab data link connector.
Access the status screen.
While the neutral switch status is being monitored on the status screen slowly remove the jumper from terminal 52 (unswitched +Battery). Now, slowly insert the jumper into terminal 52 (unswitched +Battery). Refer to Table 2.Expected Result:The switch status changes per the information in Table 2.Results:
Yes - The ECM is functioning properly. Proceed to Test Step 4.
No - The ECM is not functioning properly.Repair: Perform the following repair:
Temporarily connect a test ECM.
Remove all jumpers and replace all connectors.
Recheck the system for active diagnostic codes.
Repeat the test step.
If the problem is resolved with the test ECM, reconnect the suspect ECM.
If the problem returns with the suspect ECM, replace the ECM.
Verify that the repair eliminates the problem. STOPTest Step 4. Insert a Jumper at the Neutral Switch
Table 3
Status of the Neutral Switch Input
Condition of Switch Circuit Switch Status Circuit
The wires for the neutral switch are disconnected. OFF in gear Open
The wires for the neutral switch are connected. ON in neutral Shorted
Turn the ignition key switch to the OFF/RESET position.
Ensure that ECM vehicle harness connector J1/P1 is connected.
Find the neutral switch in the vehicle.
Disconnect the wires from the terminals of the neutral switch.
Turn the ignition key switch to the ON position.
Access the status screen on Cat ET.
While the switch status is being monitored on the status screen slowly connect the switch wires and slowly disconnect the switch wires. Refer to Table 3.Expected Result:The switch status changes per the information in Table 3.Results:
Yes - The switch is not functioning properly.Repair: Perform the following repair:Replace the faulty switch.Verify that the repair eliminates the problem.STOP
No - There is a problem in the harness between the switch and the ECM. Proceed to Test Step 5.Test Step 5. Insert a Jumper at the Bulkhead Connector