938G Series II Wheel Loader and IT38G Series II Integrated Toolcarrier Power Train Caterpillar

2. Start the engine.

3. Place the auto-shift mode switch in the MANUAL position.

Note: The highest gear available in REVERSE is third gear.

4. Disengage the parking brake and operate the machine in all speeds and in both directions using the steering column shift lever. The implement handle remote FNR switch should remain in the Neutral position.

5. Observe that the transmission operates in all gears and observe that the transmission operates in both directions.

6. Place the steering column shift lever in NEUTRAL and operated the machine in all speeds and in both directions using the implement handle remote FNR switch.

7. Observe that the transmission operates in all gears and observe that the transmission operates in both directions.

If the transmission does not operate properly and a problem in the shift lever is still suspected, perform the following test.

Illustration 1	g00987048

1. CHECK THE SHIFT LEVER SIGNAL ON THE ET STATUS SCREEN.

   1. Disconnect the FNR switch harness 4 pin connector "C-C50" that is on the shift lever. Connect a jumper wire from pin 3 to pin 4 on the shifter 4 pin connector.

   2. Connect the Electronic Technician (ET) to the machine.

   3. Turn the disconnect switch and the key start switch to the ON position.

   4. Select the powertrain ECM and go to status screen 4.

   5. Move the shift lever through all of the possible positions. Observe the status of the "Shift Lever Position" on the ET screen.

      Expected Result: The status of the shift lever position changes properly.

      Results:

      STATUS CHANGES PROPERLY - The status of the shift lever position changes properly. The diagnostic code does not exist at this time. Proceed to Test Step 5.

      STATUS ALWAYS INVALID - The status on the ET screen is "DATA FAULT" in all positions of the shifter. Proceed to Test Step 2.

      STATUS INVALID IN A POSITION - The status on the ET screen is "DATA FAULT" in a particular position. Proceed to Test Step 3.

2. CHECK FOR POWER AND GROUND AT THE SHIFTER.

   1. At the shifter, connect the positive (red) multimeter lead to wire 110-GN. Connect the negative (black) multimeter lead to wire 200-BK.

   2. Measure the voltage between the two wires.

      Expected Result: The voltage is system voltage.

      Results:

      OK - The voltage is system voltage. Proceed to Test Step 3.

      NOT OK - The voltage is not system voltage. The wiring to the shifter may have failed.

      Repair: First check the fuse for wire 110-GN. If the fuse is bad, replace the fuse. If the fuse is good, the wiring harness may have failed. Repair the wiring harness or replace the wiring harness between the fuse and the shifter or between the shifter and ground.

      STOP.

3. CHECK THE SHIFTER HARNESS AND ECM.
   Show/hide table

   Table 1

   Valid Shift Lever Input States
   Output	Forward	Neutral	Reverse	First Gear	Second Gear	Third Gear	Fourth Gear
   1F	X	O	O	X	O	O	O
   2F	X	O	O	O	X	O	O
   3F	X	O	O	O	O	X	O
   4F	X	O	O	O	O	O	X
   1N	O	X	O	X	O	O	O
   2N	O	X	O	O	X	O	O
   3N	O	X	O	O	O	X	O
   4N	O	X	O	O	O	O	X
   1R	O	O	X	X	O	O	O
   2R	O	O	X	O	X	O	O
   3R	O	O	X	O	O	X	O
   4R	O	O	X	O	O	O	X
   N	O	X	O	O	O	O	O

   1. The shift lever has three connectors.
      • 8 Pin Connector

      • 6 Pin Connector

      • 4 Pin Connector

   2. At the shifter, disconnect the 8-pin harness connector "C-C52". The 6 pin harness connector remains connected to the shifter 6 pin connector. The shifter 4 pin connector remains jumpered between pins 3 and 4.

   3. Refer to the schematic of the shifter and connect two jumper wires from the ECM connectors to frame ground in order to simulate each position of the shifter. Use the 7X-1710 Multimeter Probe in order to make the connections. If a particular position is already suspect, begin with the wires for that position.

   4. Monitor the status of the shifter on the ET screen.

      Expected Result: As each combination of contacts are grounded, the ET screen displays the corresponding shifter position.

      Results:

      OK - As each combination of contacts are grounded, the ET screen displays the corresponding shifter position. The ECM and harness appear to be working correctly.

      Repair: Replace the shifter.

      STOP.

      NOT OK - One of the combination of contacts is incorrect. The wiring harness or the ECM is not working correctly. Proceed to Test Step 4.

4. CHECK THE ECM.
   Show/hide table

   Table 2

   Machine ECM Connector Pin Assignments
   Function	Wire Assignment	Machine ECM Pin Assignments
   Forward	G750-BU	Connector J2, Pin 49
   Neutral	G763-PU	Connector J2, Pin 23
   Reverse	G755-GY	Connector J2, Pin 28
   First Gear	G768-GN	Connector J2, Pin 50
   Second Gear	G760-WH	Connector J1, Pin 41
   Third Gear	G761-YL	Connector J1, Pin 42
   Fourth Gear	G762-BR	Connector J1, Pin 43

   1. Open the machine service disconnect switch.

   2. Based on the information in table 2 remove the corresponding wires from the machine ECM harness connectors "C-C12" and "C-C13". Also use the shifter schematic for reference. After removing all of the wires shown in table 2, place DT sockets into the connectors and wire the sockets so they can be connected to frame ground individually. Be sure that the wires cannot accidentally touch frame ground.

   3. Close the machine service disconnect switch. Power up the machine with the key in the run position, and connect and start up the ET service tool.

   4. Select the powertrain ECM and go to status screen 4.

   5. Monitor the status of the shifter on the ET screen.

      Expected Result: As each combination of contacts are grounded, the ET screen displays the corresponding shifter position.

      Results:

      OK - As each combination of contacts are grounded, the ET screen displays the corresponding shifter position. The ECM is working properly. The wiring harness may have failed.

      Repair: Repair the wiring harness or replace the wiring harness.

      STOP.

      NOT OK - One of the combinations of contacts does not cause the proper status to be displayed. The ECM may have failed.

      Repair: Clean the contacts for the ECM harness connectors. It is unlikely that the ECM has failed. Exit this procedure and perform this entire procedure again. If the problem remains, replace the ECM. It is preferable to show that the new ECM corrects the problem and that the suspect ECM demonstrates the problem.

      STOP.

5. VERIFY SHIFT LEVER REMOTE FNR SWITCH FUNCTIONALITY.

   1. Place shift lever on the steering column in Neutral and First Gear.

   2. At the shifter 4 pin connector, remove the jumper wire between pin 3 and pin 4.

   3. Connect 4 pin receptacle, connector "C-C50" from the cab harness onto the shifter 4 pin plug. This will enable the remote FNR switch circuit for the shift handle

   4. Insure that the pins and sockets are seated properly, and that the connector mates correctly.

   5. Place the remote FNR switch in the FORWARD position.

   6. Verify that ET shows "F1" as desired gear.

   7. Place the remote FNR switch in the REVERSE position.

   8. Verify that ET shows "R1" as desired gear.

      Expected Result: As each combination is switched, the ET screen displays the corresponding gear and direction.

      Results:

      STATUS CHANGES PROPERLY - The status of the shift lever position changes properly. Monitor the machine to see if the problem occurs. If the problem occurs, repeat the entire test procedure again.

      STOP.

      STATUS INVALID - The status on the ET screen is "DATA FAULT" in either a particular position or all positions. Proceed to Test Step 6.

6. VERIFY SHIFT LEVER REMOTE FNR HARNESS.

   1. Ensure shift lever on the steering column is in Neutral and First Gear.

   2. Assure that the cab harness 4 pin receptacle Connector "C-C50" is connected to the shifter 4 pin plug.

   3. Disconnect the 6 pin connector that goes to the remote FNR switch assembly.

   4. On the cab harness connector "C-C23", place a jumper wire from pin 1 202-BK to pin 4 G787-GN.

   5. Verify that ET shows "F1" as the desired gear.

   6. Move the jumper wire connection so that is from pin 1 202-BK to pin 6 G788-YL.

   7. Verify that ET shows "R1" as the desired gear.

   8. Move the jumper wire connection so that is from pin 1 202-BK to pin 5 P916-OR.

   9. Verify that ET shows "N1" as the desired gear.

      Expected Result: As each jumper pin combination is checked, the ET screen displays the corresponding gear and direction.

      Results:

      STATUS CHANGES PROPERLY - The status of the shift lever position changes properly. The harness from the remote FNR switch assembly to the ECM is working correctly.

      Repair: Replace the remote FNR switch assembly.

      STOP.

      STATUS ALWAYS INVALID - The status on the ET screen is "DATA FAULT" no matter which wire is jumpered to pin 1. The common signal pin 1 202-BK may have lost connection to machine ground. The wiring harness may have failed.

      Repair: Replace the wiring harness or repair the wiring harness.

      STOP.

      STATUS INVALID WHEN A PARTICULAR WIRE IS JUMPERED - The status on the ET screen is "DATA FAULT" when a particular wire is jumped to pin 1. The wiring harness may have failed.

      Repair: Replace the wiring harness or repair the wiring harness.

      STOP.