83056M Mariner NUT

Illustration 1 g00864414
Typical circuit schematic for the service brake pedal position (switch 1)The return wire may be connected to P1-3, P1-5, or P1-18.Test Step 1. Inspect Electrical Connectors and Wiring.
Illustration 2 g01152482
Pin locations on ECM connector (P1-5) AP sensor/switch sensor common (P1-45) Service brake pedal position switch
Thoroughly inspect ECM vehicle harness connector J1/P1, the firewall bulkhead connector and the terminals for the following switches in the connectors:
Terminal 5 (AP Sensor/Switch Sensor Common )
Terminal 45 (Service Brake Pedal Position (Switch 1))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: Perform the following 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 Service Brake Switch on Caterpillar Electronic Technician (ET)
Table 1
Table for Status of the Service Brake Pedal Position    
Switch Position or Pedal Position    Status    Circuit    
The service brake pedal is depressed.     OFF     Open    
The service brake pedal is released.     ON     Closed    
Access the Cat ET status screen.
Turn the ignition key switch to the ON position.
Depress the service brake while the status of the service brake pedal position (switch 1) is being observed. Also, release the service brake while the status of the service brake pedal position (switch 1) is being observed.Refer to Table 1 for the status of the switch or for the status of the pedal position.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
Table 2
Table for Status of Service Brake Pedal Position (Switch 1)    
Condition of Switch Circuit    Switch Status    Circuit    
Terminal 45 is open.     ON     Open    
Terminal 45 connected to terminal 5.     OFF     Shorted    
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 45 (Service Brake Pedal Position Switch 1) of the breakout T. Connect the other end of the jumper to P1-5 (AP sensor/switch sensor common) 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 Cat ET status screen.
While the status of the service brake pedal position (switch 1) is being monitored on the Cat ET status screen slowly remove the jumper from terminal 5 and slowly insert the jumper from terminal 5 (AP sensor/switch sensor common).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 Service Brake Pedal Position (Switch 1)
Table 3
Table for Status of the Service Brake Pedal Position (Switch 1)    
Condition of Switch Circuit    Switch Status    Circuit    
The wires for the service brake pedal position switch 1 are disconnected.     ON     Open    
The wires for the service brake pedal position switch 1 are connected.     OFF     Shorted    
Turn the ignition key switch to the OFF/RESET position.
Ensure that ECM vehicle harness connector J1/P1 is connected.
Find the switch for the service brake pedal position (switch 1) in the vehicle.
Disconnect the wires from the switch terminals.
Turn the ignition key switch to the ON position.
Verify