938 Shift Lever Troubleshooting
February 13, 2023 | Author: Anonymous | Category: N/A
Short Description
Download 938 Shift Lever Troubleshooting...
Description
938G Wheel Loader 6WS00001-UP (MACHINE) POWERED BY 3126 Engine(SEBP25... Page 1 of 10
Shutdown SIS Previous Screen
Product: WHEEL LOADER Model: 938G WHEEL LOADER 6WS Configuration: 938G Wheel Loader 6WS00001-UP (MACHINE) POWERED BY 3126 Engine
Troubleshooting IT28G and IT38G Integrated Toolcarriers and 924G, 924GZ, 928G and 938G Wheel Loaders Power Train Electronic Control System Media Number -SENR1218-05
Publication Publication Date -01/10/2001
Date Updated -25/10/2001
i01600489
Transmission Control (Shift Lever) SMCS - 3065-038 System Operation Description:
https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/sisweb... 26/01/2018 938G Wheel Loader 6WS00001-UP (MACHINE) POWERED BY 3126 Engine(SEBP25... Page 2 of 10
Illustration 1
g00821347
Schematic of the Circuit for the Shift Lever
Note: Before troubleshooting the shift lever, move the shift lever through all positions. Check for any active diagnostic codes.
This procedure relates to the shift lever and to the components of the harness that are related to the shift lever. When measurements are taken, use u se the 146-4080 Digital Multimeter, or an equivalent Multimeter. Use the 7X-1708 Multimeter Probe. Connect the spoons to the positive lead and the negative lead. Check the related circuits for opens and shorts in the harness, and measure the resistance of the wire.
https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/sisweb... 26/01/2018 938G Wheel Loader 6WS00001-UP (MACHINE) POWERED BY 3126 Engine(SEBP25... Page 3 of 10
Reference the electrical schematic of the machine. The schematic is used in order to quickly locate the wiring that is related to the shift lever. Test Step 1. CHECK FOR AN INTERMITTENT I NTERMITTENT CONNECTION
Use the Electronic Technician (ET) when this test step is performed. A. Connect Connect the the ET to the the machin machine. e. B. Turn the key start start switch switch and the disconnect disconnect switch switch to the ON positio position. n. C. Star Startt the the ET. ET. Note: The ET will initiate communications with the Electronic Control Modules on the machine. After communication has been be en established, the ET will list the Electronic Control Modules on the machine.
D. Select the the desired desired Electroni Electronicc Control Control Module. Module. E. Select "diagnosti "diagnostics" cs" from the main menu. Then, select "active "active diagnostics" diagnostics" from the drop-down drop-down menu. F. Monitor Monitor the active diagnosti diagnosticc screen while each of the harnesses harnesses and the connectors connectors that are connected to the component is wiggled. Note: If the harness wiggled and the diagnostic code disappears, there is a problem in the wiring or the connector.
G. From the Status screen, screen, monitor monitor the shift shift lever as the harnesses harnesses are wiggled wiggled.. Note: If the harness is wiggled and the reading changes c hanges erratically, there is a problem in the wiring or the connector. Expected Result:
Wiggling the harnesses or the connectors does NOT have an effect on the status of a diagnostic code or the operation of the shift lever. Results:
• OK - Wiggling the harnesses or the connectors does NOT have an effect on the status of a diagnostic code or the operation of the shift lever. Proceed to test step 2. • NOT OK - Wiggling the harnesses or the connectors has an effect on the status of a diagnostic code or the operation of the shift lever. Repair: Repair the harness and/or connectors or replace the harness and/or con connectors nectors that are causing the problem. Stop. Test Step 2. INSPECT THE ELECTRICAL EL ECTRICAL CONNECTORS.
https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/sisweb... 26/01/2018 938G Wheel Loader 6WS00001-UP (MACHINE) POWERED BY 3126 Engine(SEBP25... Page 4 of 10
A. Perform Perform the "Electrical "Electrical Connector Connector - Inspect" procedure procedure in this this manual. Expected Result:
Every test step in the "Electrical Connector - Inspect" Ins pect" procedure has an OK result. Results:
• OK - Every test step in the "Electrical Connector - Inspect" procedure has an OK result. Proceed to test step 3. • NOT OK - One of the test steps in the "Electrical Connector - Inspect" procedure has an NOT OK result. Repair: Follow the recommended repair that is provided in the "Electrical Connector - Inspect" procedure. Stop. Test Step 3. CHECK THE DATE CODE OF THE SHIFT LEVER.
Some shift lever may experience any of the following failure modes: • Interm Intermitt ittent ent operation operation of of the speed speed function function • Disabl Disabling ing of the speed speed output (transm (transmissi ission on neutralizer neutralizer)) • Speed out output put remains remains in in the last last valid valid speed. speed. A. Check the shift lever lever for for a suspect suspect date date code. code. Note: A problem is limited to certain dates of manufacturing for the shift lever. There is a date code with six Alpha-characters on the bottom of the shift lever. The last four characters of the suspect date codes are "NRNN", "NANN", "NLNN", "NKNN", "NONN", and "NDNN". Expected Result:
The shift lever DOES NOT have a suspect date code. Results:
• OK - The shift lever DOES NOT have a suspect date code. Follow the remaining Troubleshooting procedure if a problem exists with the shift lever. Additional service information will be announced as the information becomes available. Proceed to test step 4. • NOT OK - The shift lever has a suspect date code. Repair: Replace the shift lever. Stop. Test Step 4. CHECK THE SHIFT LEVER. LE VER.
https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/sisweb... 26/01/2018 938G Wheel Loader 6WS00001-UP (MACHINE) POWERED BY 3126 Engine(SEBP25... Page 5 of 10
A. The ECM and the shift shift lever remain remain connected connected to the wiring wiring harness. harness. B. The disconnect disconnect switch switch and the key start start switch switch are in the ON position. position. C. The remote remote direction direction switch switch is in in the NEUTRAL NEUTRAL position. position. D. Place the shift shift lever is is in the position position with the problem, problem, if known. known. E. At the harness connector for the ECM, measure the voltages from contact 2 (wire 202-BK) to the following contacts at the shift lever: ◦
Contacts 1 to 8 (8 Pin Connector)
◦
Contacts 1,2, 5, and 6 (6 Pin Connector)
◦
Contacts 1,2, and 3 (4 Pin Connector)
F. Compare the the measurement measurementss with the the following following tables. tables. Table 1
FNR Switch
Shift Lever Pos.
Key Start Switch Pos.
1st Gear
2nd Gear
3rd Gear
4th Gear
Start Relay
Neut. Out
Rev Out
Fwd Out
1
2
3
4
5
6
7
8
8 P in
8 Pin
8 Pin
8 Pin
8 Pin
8 Pin
8 Pin
VDC
VDC
VDC
VDC
VDC
VDC
VDC
0.11
3.53
3.53
3.53
0.02
3.54
3.52
0.11
3.53
0.11
3.53
3.53
0.02
3.54
3.51
0.11
3.53
3.53
0.11
3.53
0.02
3.53
3.51
0.11
3.53
3.53
3.53
0.11
0.02
3.54
3.51
0.11
0.11
3.51
3.51
3.51
27.05
0.11
3.49
3.51
0.11
3.53
3.53
3.53
0.02
3.53
0.11
3.53
3.53
0.11
3.53
3.53
0.02
3.53
0.11
3.53
8 Pin VDC
N
1F
Run
N
2F
Run
N
3F
Run
N
4F
Run
N
N
Run
N
1R
Run
N
2R
Run
https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/sisweb... 26/01/2018 938G Wheel Loader 6WS00001-UP (MACHINE) POWERED BY 3126 Engine(SEBP25... Page 6 of 10
N
3R
Run
3.53
3.53
0.11
3.53
0.02
3.53
0.11
3.53
Table 2
FNR Switch
Shift Lever Pos.
Key Start Switch Pos.
+ Battery
Ground
Backup Key Switch Alarm (Out) (In)
1
2
5
6
6 Pin
6 Pin
6 Pin
6 Pin
VDC
VDC
VDC
VDC
N
1F
Run
27.99
0.02
27.94
27.94
N
2F
Run
27.99
0.02
27.95
27.94
N
3F
Run
27.99
0.02
27.94
27.94
N
4F
Run
27.99
0.02
27.94
27.94
N N
N 1R
Run Run
28.01 27.97
0.01 0.03
27.92 27.93
27.95 0.63
N
2R
Run
27.97
0.03
27.93
0.63
N
3R
Run
27.97
0.03
27.93
0.63
Table 3
FNR Switch
Shift Lever Pos.
Key Start Switch Pos.
Fwd Switch In
Rev Switch In
Neutral Switch Input
1
2
3
4 Pin
4 Pin
4 Pin
VDC
VDC
VDC
N
1F
Run
27.93
27.93
0.03
N
2F
Run
27.93
27.93
0.02
N
3F
Run
27.93
27.93
0.02
N
4F
Run
27.93
27.93
0.02
N
N
Run
27.94
27.94
0.03
N N
1R 2R
Run Run
27.92 27.92
27.92 27.92
0.03 0.03
https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/sisweb... 26/01/2018 938G Wheel Loader 6WS00001-UP (MACHINE) POWERED BY 3126 Engine(SEBP25... Page 7 of 10
N
3R
Run
27.92
27.92
0.03
Expected Result:
The voltage that is measured is within the specification of ± 0.10 VDC. See the tables that are provided. Results:
• OK - The voltage that is measured is within the specification of ± 0.10 VDC. Proceed to test step 5. • NOT OK - One or more of the measured voltages are NOT within the specification. Inspect the wiring harness from the ECM to the shift lever. Check C heck for damaged components or loose connections in the harness. Repair: Ensure that the fuse and the circuit breaker for the transmission controls are in the proper working condition. Inspect the ground strap for the ECM. Verify that the ground strap is secure and undamaged. There should be continuity in the wiring harness between the shift lever and the ECM for the power and ground circuits. Repair any failed components or replace any failed components with the recommended Caterpillar C aterpillar parts. Stop. Test Step 5. CHECK THE WIRING HARNESS FOR SHORT CIRCUIT CONDITIONS.
A. Turn the key start start switch switch and the disconnect disconnect switch switch to the OFF position. position. B. Disconnect Disconnect the ECM and and the shift lever lever from the wiring wiring harness. harness. C. At the harness connector for the ECM, measure the resistance from contact 20 (Wire G768-GN) to all other contacts. D. At the harness connector connector for the the ECM, measure the resistanc resistancee from contact contact 21 (Wire G760WH) to all other contacts. E. At the harness connector for the ECM, measure the resistance from contact 22 (Wire G761-YL) to all other contacts. F. At the harness connector connector for the the ECM, measure the resistanc resistancee from contact contact 23 (Wire G762-BR) G762-BR) to all other contacts. G. At the harness connector for the ECM, measure the resistance from contact 10 (Wire G763-PU) to all other contacts. H. At the harness connector for the ECM, measure the resistance from contact 17 (Wire G755-GY) to all other contacts. I. At the harness harness connector for for the ECM, measure the resistance from contact15 (Wire (Wire G750-BU) to all other contacts.
https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/sisweb... 26/01/2018 938G Wheel Loader 6WS00001-UP (MACHINE) POWERED BY 3126 Engine(SEBP25... Page 8 of 10
Expected Result:
The resistance for each measurement is greater than 5000 ohms. Results:
• OK - The resistance for each measurement is greater than 5000 ohms. Proceed to test step 6. • NOT OK - The resistance that is measured is less than 5 ohms o hms for one or more of the measurements. Repair: Repair the wiring harness or replace rep lace the wiring harness. Stop. Test Step 6. CHECK THE HARNESS FOR F OR AN OPEN CIRCUIT. Note: Measure the resistance of the appropriate wires. For example, the shift lever operates properly in every direction except the FIRST SPEED FORWARD position. Then, perform the appropriate a ppropriate test steps.
A. The key start switch switch and the disconnec disconnectt switch switch remain in the OFF positi position. on. B. The ECM and the shift shift lever remain remain disconnecte disconnected d from the wiring wiring harness. harness. C. At the harness connector for the ECM, measure the resistance from contact 20 (Wire G768-GN) to contact 1 (Wire G768-GN) at the six s ix pin connector for the shift lever. D. At the harness connector connector for the the ECM, measure the resistanc resistancee from contact contact 21 (Wire G760WH) to contact 2 (Wire G760-WH) at the six pin connector for the shift lever. E. At the harness connector for the ECM, measure the resistance from contact 22 (Wire G761-YL) to contact 3 (Wire G761-YL) at the six pin connector for the shift lever. F. At the harness connector connector for the the ECM, measure the resistanc resistancee from contact contact 23 (Wire G762-BR) G762-BR) to contact 4 (Wire G762-BR) at the six pin connector for the shift lever. G. At the harness connector for the ECM, measure the resistance from contact 10 (Wire G763-PU) to contact 6 (Wire G763-PU) at the six pin connector for the shift lever. H. At the harness connector for the ECM, measure the resistance from contact 17 (Wire G755-GY) to contact 7 (Wire G755-GY) at the eight e ight pin connector for the shift lever. I. At the harness connector for the ECM, measure the resistance from contact 15 (Wire G750-BU) to contact 8 (Wire G750-BU) at the eight pin connector for the shift lever. Expected Result:
The resistance for each measurement is less than tha n 5 ohms. Results:
https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/sisweb... 26/01/2018 938G Wheel Loader 6WS00001-UP (MACHINE) POWERED BY 3126 Engine(SEBP25... Page 9 of 10
• OK - The resistance for each measurement is less than 5 ohms. Proceed to test step 7. • NOT OK - The resistance for one or more of the measurements is greater than 5000 ohms. A problem exists in the harness. Repair: Repair the harness or replace the harness. Stop. Test Step 7. VERIFY THAT THE SHIFT S HIFT LEVER IS OPERATING CORRECTLY.
A. Connect the the ECM and the shift shift lever lever to the wirin wiring g harness. harness. B. Turn the disconnect disconnect switch switch and the key key start switch switch to the ON positio position. n. C. Shift the transmission through every gear and shift the transmission transmission through every direction position. D. Check the shift lever lever for for proper proper operation. operation. Expected Result:
The shift lever problem remains. Results:
• YES - The shift lever problem remains. The condition has h as not been corrected. The transmission electronic control module may have failed. Proceed to test step 8. • NO - The shift lever is operating correctly. The problem was probably p robably caused by a poor electrical connection. Repair: Resume normal operation and watch for a reoccurence of the problem. Stop. Test Step 8. VERIFY THAT THE TRANSMISSION TRA NSMISSION ELECTRONIC CONTROL MODULE HAS FAILED.
A. Turn the key start start switch switch and the disconnect disconnect switch switch to the OFF position. position. B. Disconnect Disconnect the shift shift lever lever from from the wiring wiring harness. harness. C. Create a jumper jumper wire that that can short from from contact contact 2 on the six pin connector connector to two of the pins pins on the eight pin connector on the wiring harness. D. Turn the disconnect disconnect switch switch and the key key start switch switch to the ON positio position. n. E. Use the ET to display display "Group "Group 1 Gear Lever Paramet Parameters" ers".. F. Connect the the jumper from from pin 2 (6 pin connector) connector) to pins 1 and and 8 (8 pin connector). connector). The gear lever should read "1" on the display.
https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/sisweb... 26/01/2018 938G Wheel Loader 6WS00001-UP (MACHINE) POWERED BY 3126 Engine(SEBP... Page 10 of 10
G. Connect the jumper from pin 2 (6 pin connector) to pins 2 and 8 (8 pin connector). The gear lever should read "2" on the display. H. Connect the jumper from pin 2 (6 pin connector) to pins 3 and 8 (8 pin connector). The gear lever should read "3" on the display. I. Connect the the jumper from from pin 2 (6 pin connector) connector) to pins 4 and and 8 (8 pin connector). connector). The gear lever should read "4" on the display. J. Connect the jumper from pin 2 (6 pin connector) to pins 1 and 7 (8 pin connector). The gear lever should read "1R" on the display. K. Connect the jumper from pin 2 (6 pin connector) to pins 2 and 7 (8 pin connector). The gear lever should read "2R" on the display. L. Connect the the jumper from from pin 2 (6 pin connector) connector) to pins 3 and and 7 (8 pin connector). connector). The gear lever should read "3R" on the display. M. Connect the jumper from pin 2 (6 pin connector) to pins 4 and 7 (8 pin connector). The gear lever should read "4R" on the display. N. Connect the jumper from pin 2 (6 pin connector) to pins 4 and 6 (8 pin connector). The gear lever should read "N" on the display. Expected Result:
All of the gear parameters are correct. c orrect. Results:
• OK - All of the gear parameters are correct. The problem is due to a prob problem lem in either the wiring harness or the shift lever. Exit this procedure and perform this procedure again. Stop. • NOT OK - All of the gear parameters are NOT correct. The ECM may have failed. Repair: It is unlikely that the ECM has failed. Exit this procedure and perform this procedure again. If the cause of the problem is not found, replace the ECM. Refer to Testing and Adjusting, "Electronic Control Module (ECM) - Replace". Stop.
Copyright 1993 - 2018 Caterpillar Inc. All Rights Reserved. Private Network For SIS Licensees.
Fri Jan 26 14:55:08 EST 2018
View more...
Comments
