0002129 WRENCH Caterpillar parts WRENCH
Alternative (cross code) number:
Illustration 1 g01004497
Schematic of the Decelerator Switch for the Joystick Control
Switch Circuits at the ECM Connector
State    Connector Contact    Switch Connector
Contact    Wire Number    Status
Not Activated     J1-42
N/O     N/O (1)     F774-WH     O (2)
N/C N/C (3)     R981-YL     G (4)
N/O     N/O     F774-WH     G
N/C N/C     R981-YL     O
( 1 ) Normally Open
( 2 ) Open
( 3 ) Normally Closed
( 4 ) GroundedThis 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 failure 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 (J764-BR) and the ECM.
There is an open wire between the normally open contact of the switch and the ECM.
There is an open wire between the normally closed contact of the switch and the ECM.
The switch has failed.
The ECM has failed. This is unlikely. Note: Ensure that the diagnostic code is on hold and that the diagnostic indicator is illuminated. System Response:The action lamp is ON. The diagnostic code will cause the switch to stop functioning. Other machine operations will not be affected.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 J1-70 (the return circuit) to the Normally Closed contact and to the Normally Open contact. See table 1.
Measure the resistance when the switch is activated and 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. The switch or the machine harness has failed. Proceed to Test Step 2.Test Step 2. CHECK THE SWITCH CIRCUIT AT THE JOYSTICK CONTROL.
Switch Circuits at the Connector for the Joystick
State    8 Pin Connector
Contact    Wire Color    Status
Decelerator Switch         1     COMMON     BK
Not Activated 7     N/O (1)     RD     O (2)
5 N/C (3)     YL     G (4)
Activated 7     N/O     RD     G
5 N/C     YL     O
( 1 ) Normally Open.
( 2 ) Open.
( 3 ) Normally Closed
( 4 ) Grounded
The switch has a 8-pin connector that will join to the machine harness. The connector can be accessed by removing the mounting plate for the joystick control on the left console.
Disconnect the 8 contact