COIL AS 6T6886 - Caterpillar

Illustration 1 g01177077
Schematic of the Forward SwitchThis diagnostic code is for the forward switch.
Table 1
Switch Circuits at the ECM Connector    
CID/
Switch    Switch
State    ECM Connector
and Contact No.    Switch Connector
Contact    Wire No.    Status    
CID 2121
Forward
Switch     Not Activated     J2-36 N/O     N/O (1)     E914-BU     O (2)    
J2-37 N/C N/C (3)     E915-GY     G (4)    
Activated J2-36 N/O     N/O     E914-BU     G    
J2-37 N/C N/C     E915-GY     O    
( 1 ) N/O = Normally Open.
( 2 ) O = Open.
( 3 ) N/C = Normally Closed.
( 4 ) G = Grounded.This switch has two inputs to the ECM. The inputs are Normally Open and Normally Closed. During normal operation, one of the inputs is open and the other input is grounded. A problem is detected when both inputs are in the same state at the same time. The possible causes of this diagnostic code are listed below:
There is an open wire between the common circuit for the switch (202-BK) and the ECM.
There is an open or grounded wire between the Normally Open contact of the switch (E914-BU) and the ECM.
There is an open or grounded wire between the Normally Closed contact of the switch (E915-GY) and the ECM.
The switch has failed.
The ECM has failed. This is unlikely. Test Step 1. CHECK THE CIRCUIT FOR PROPER OPERATION.
Turn the key start switch to the OFF position.
Disconnect the machine harness connectors J1 and J2 from the ECM.
At machine harness connector J1, measure the resistance from J1-13 (the return circuit) to the Normally Closed contact (E915-GY) and to the Normally Open contact (E914-BU). See table 1.
Measure the resistance while the switch is activated. Also, measure the resistance while the switch is not activated.Expected Result:The measurement is the same value as the value that is listed in table 1.Results:
OK - The value that is measured matches the value that is listed in the table. Proceed to Test Step 3.
NOT OK - The value that is measured does not match the value that is listed in the table. Proceed to Test Step 2.Test Step 2. CHECK THE SWITCH CIRCUIT AT THE SWITCH.
At the switch, disconnect the three wires from the switch.
At the switch, measure the resistance between the common contact and each of the Normally Closed contact and the Normally Open contact. See table 1.
Measure the resistance while the switch is activated. Also, measure the resistance while the switch is not activated.Expected Result:The measurement is the same value as the value in table 1.Results:
OK - The value that is measured matches the value that is listed in the table.Repair: The machine harness has failed. The return circuit (202-BK) could be open. The Normally Open circuit or the Normally Closed circuit could be open or shorted in the machine harness. Repair the machine harness or replace the machine harness.STOP
NOT OK - The value that is measured does not match the value that is listed in the table.Repair: The switch