AXLE GP 1937362 - Caterpillar

Illustration 1 g01625851This diagnostic code is for the push button switch (upshift).
Table 1
Switch Circuits at the ECM Connector
CID/
Switch Switch
State ECM Connector
and Contact No. Switch Connector
Contact Wire No. Status
CID 0622
Upshift
Switch Not Activated J2-28 N/O N/O(1) F785-WH(White) O(2)
J2-29 N/C N/C(3) F783-GN(Green) G(4)
Activated J2-28 N/O N/O F785-WH(White) G
J2-29 N/C N/C F783-GN(Green) 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 failure is detected when both inputs are in the same state at the same time. The transmission will fail to downshift when the downshift switch is pressed. The possible causes of this diagnostic code are listed below:
There is an open wire between the common circuit (202-BK(Black)) 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. 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 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 CONSOLE.
Table 2
Switch Circuits at the Console Connector
CID/
Switch Switch
State 6-Pin Connector
Contact No. Switch
Contact Wire Color Status
CID 0622
Upshift
Switch 2 COMMON PK
Not Activated 6 N/O(1) GN O(2)
1 N/C(3) WH G(4)
Activated 6 N/O GN G
1 N/C WH O
(1) N/O = Normally Open.
(2) O = Open.
(3) N/C = Normally Closed.
(4) G = Grounded.
The upshift switch and the downshift switch have a connector with 6 contacts which will join to the machine harness. The 6 contact connector can be accessed by removing the mounting plate for the parking brake switch on the left console.
Disconnect the 6 contact connector of the switches from the machine harness.
Measure the resistance between the common contact and the Normally Closed contact. Measure the resistance between the common contact and the Normally Open contact. See table 2.
The measurement is the same value as the value that is listed in table 2. 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(Black)), the Normally Open circuit, or the Normally Closed circuit is open in the machine harness.