Question about message "Service 4WD"
10-01-2005, 05:44 PM
#11
Document ID# 1696742
2000 Chevrolet Chevy K Silverado - 4WD
--------------------------------------------------------------------------------
Intermittent Service 4WD Light Comes On with DTC C0306 or C0308 Stored in TCCM - keywords 246 246EAU 263 263EAU case light NP1 NP8 #PIP3526 - (Aug 18, 2005)
Intermittent Service 4WD Light Comes On With DTC C0306 or C0308 Stored In TCCM
1999-2005 Cadillac Escalade
1999-2005 Chevrolet Avalanche, Silverado, Suburban, Tahoe
1999-2005 GMC Sierra, Yukon, Yukon XL
Equipped with Transfer Case (RPO - NP8 or NP1)
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
Service 4WD light comes on while trying to change transfer case modes. Condition may be intermittent. DTC C0306 OR C0308 will be set in the transfer case control module.
Recommendation/Instructions:
If published diagnostics do not lead to a correction, check all engine grounds for poor connection. These grounds are not shown on any transfer case schematics but if not clean and tight, components grounding through the suspect grounds can then seek other ground paths and interfere with transfer case operation. Battery cable engine grounds as well as grounds located on the back of the engine cylinder heads are possible sources of this concern.
Also make sure grounds are mounted to the correct location. For example, a ground that should be on the frame possibly moved to the core support during a previous repair may also cause this concern.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION
© Copyright General Motors Corporation. All Rights Reserved.
--------------------------------------------------------------------------------
Document ID# 1696742
2000 Chevrolet Chevy K Silverado - 4WD
2000 Chevrolet Chevy K Silverado - 4WD
--------------------------------------------------------------------------------
Intermittent Service 4WD Light Comes On with DTC C0306 or C0308 Stored in TCCM - keywords 246 246EAU 263 263EAU case light NP1 NP8 #PIP3526 - (Aug 18, 2005)
Intermittent Service 4WD Light Comes On With DTC C0306 or C0308 Stored In TCCM
1999-2005 Cadillac Escalade
1999-2005 Chevrolet Avalanche, Silverado, Suburban, Tahoe
1999-2005 GMC Sierra, Yukon, Yukon XL
Equipped with Transfer Case (RPO - NP8 or NP1)
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
Service 4WD light comes on while trying to change transfer case modes. Condition may be intermittent. DTC C0306 OR C0308 will be set in the transfer case control module.
Recommendation/Instructions:
If published diagnostics do not lead to a correction, check all engine grounds for poor connection. These grounds are not shown on any transfer case schematics but if not clean and tight, components grounding through the suspect grounds can then seek other ground paths and interfere with transfer case operation. Battery cable engine grounds as well as grounds located on the back of the engine cylinder heads are possible sources of this concern.
Also make sure grounds are mounted to the correct location. For example, a ground that should be on the frame possibly moved to the core support during a previous repair may also cause this concern.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION
© Copyright General Motors Corporation. All Rights Reserved.
--------------------------------------------------------------------------------
Document ID# 1696742
2000 Chevrolet Chevy K Silverado - 4WD
10-01-2005, 05:45 PM
#12
Document ID# 877978
2000 Chevrolet Chevy K Silverado - 4WD
--------------------------------------------------------------------------------
Service 4WD Indicator Illuminated, DTC B2725 Set (Replace Transfer Case Shift Control Switch) #02-04-21-004 - (Apr 15, 2002)
"Service 4WD" Indicator Illuminated, DTC B2725 Set (Replace Transfer Case Shift Control Switch)
1999-2002 Chevrolet and GMC C/K Pickup and Utility Models (Silverado, Sierra, Avalanche, Suburban, Tahoe, Yukon, Yukon XL)
with Four Wheel Drive and NVG 236/246 Transfer Case (RPO NP8)
Condition
Some customers may comment on the Service 4WD indicator illuminating. Upon investigation, the technician may find DTC B2725 set.
Cause
The condition may be due to a intermittent fault in the transfer case shift control switch.
Correction
Important
The transfer case shift control module should not need replacement. DO NOT replace P/N 15749703 unless diagnosis points to the module as the malfunction.
Replace the transfer case shift control switch using published Service Information procedures.
Parts Information
Part Number
Description
15709327
Transfer Case Shift Control Switch
Parts are currently available from GMSPO.
Warranty Information
For vehicles repaired under warranty, use:
Labor Operation
Description
Labor Time
K4123
Switch, Transfer Case Select - Replace
Use published labor operation time
GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION
© Copyright General Motors Corporation. All Rights Reserved.
--------------------------------------------------------------------------------
Document ID# 877978
2000 Chevrolet Chevy K Silverado - 4WD
2000 Chevrolet Chevy K Silverado - 4WD
--------------------------------------------------------------------------------
Service 4WD Indicator Illuminated, DTC B2725 Set (Replace Transfer Case Shift Control Switch) #02-04-21-004 - (Apr 15, 2002)
"Service 4WD" Indicator Illuminated, DTC B2725 Set (Replace Transfer Case Shift Control Switch)
1999-2002 Chevrolet and GMC C/K Pickup and Utility Models (Silverado, Sierra, Avalanche, Suburban, Tahoe, Yukon, Yukon XL)
with Four Wheel Drive and NVG 236/246 Transfer Case (RPO NP8)
Condition
Some customers may comment on the Service 4WD indicator illuminating. Upon investigation, the technician may find DTC B2725 set.
Cause
The condition may be due to a intermittent fault in the transfer case shift control switch.
Correction
Important
The transfer case shift control module should not need replacement. DO NOT replace P/N 15749703 unless diagnosis points to the module as the malfunction.
Replace the transfer case shift control switch using published Service Information procedures.
Parts Information
Part Number
Description
15709327
Transfer Case Shift Control Switch
Parts are currently available from GMSPO.
Warranty Information
For vehicles repaired under warranty, use:
Labor Operation
Description
Labor Time
K4123
Switch, Transfer Case Select - Replace
Use published labor operation time
GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION
© Copyright General Motors Corporation. All Rights Reserved.
--------------------------------------------------------------------------------
Document ID# 877978
2000 Chevrolet Chevy K Silverado - 4WD
10-01-2005, 05:46 PM
#13
Document ID# 1696742
2003 Chevrolet Chevy K Silverado - 4WD
--------------------------------------------------------------------------------
Intermittent Service 4WD Light Comes On with DTC C0306 or C0308 Stored in TCCM - keywords 246 246EAU 263 263EAU case light NP1 NP8 #PIP3526 - (Aug 18, 2005)
Intermittent Service 4WD Light Comes On With DTC C0306 or C0308 Stored In TCCM
1999-2005 Cadillac Escalade
1999-2005 Chevrolet Avalanche, Silverado, Suburban, Tahoe
1999-2005 GMC Sierra, Yukon, Yukon XL
Equipped with Transfer Case (RPO - NP8 or NP1)
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
Service 4WD light comes on while trying to change transfer case modes. Condition may be intermittent. DTC C0306 OR C0308 will be set in the transfer case control module.
Recommendation/Instructions:
If published diagnostics do not lead to a correction, check all engine grounds for poor connection. These grounds are not shown on any transfer case schematics but if not clean and tight, components grounding through the suspect grounds can then seek other ground paths and interfere with transfer case operation. Battery cable engine grounds as well as grounds located on the back of the engine cylinder heads are possible sources of this concern.
Also make sure grounds are mounted to the correct location. For example, a ground that should be on the frame possibly moved to the core support during a previous repair may also cause this concern.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION
© Copyright General Motors Corporation. All Rights Reserved.
--------------------------------------------------------------------------------
Document ID# 1696742
2003 Chevrolet Chevy K Silverado - 4WD
2003 Chevrolet Chevy K Silverado - 4WD
--------------------------------------------------------------------------------
Intermittent Service 4WD Light Comes On with DTC C0306 or C0308 Stored in TCCM - keywords 246 246EAU 263 263EAU case light NP1 NP8 #PIP3526 - (Aug 18, 2005)
Intermittent Service 4WD Light Comes On With DTC C0306 or C0308 Stored In TCCM
1999-2005 Cadillac Escalade
1999-2005 Chevrolet Avalanche, Silverado, Suburban, Tahoe
1999-2005 GMC Sierra, Yukon, Yukon XL
Equipped with Transfer Case (RPO - NP8 or NP1)
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
Service 4WD light comes on while trying to change transfer case modes. Condition may be intermittent. DTC C0306 OR C0308 will be set in the transfer case control module.
Recommendation/Instructions:
If published diagnostics do not lead to a correction, check all engine grounds for poor connection. These grounds are not shown on any transfer case schematics but if not clean and tight, components grounding through the suspect grounds can then seek other ground paths and interfere with transfer case operation. Battery cable engine grounds as well as grounds located on the back of the engine cylinder heads are possible sources of this concern.
Also make sure grounds are mounted to the correct location. For example, a ground that should be on the frame possibly moved to the core support during a previous repair may also cause this concern.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION
© Copyright General Motors Corporation. All Rights Reserved.
--------------------------------------------------------------------------------
Document ID# 1696742
2003 Chevrolet Chevy K Silverado - 4WD
10-01-2005, 05:47 PM
#14
Document ID# 1677268
2003 Chevrolet Chevy K Silverado - 4WD
--------------------------------------------------------------------------------
Service 4WD Light Illuminated, DTC C0374 Set (Inspect Wiring Harness to Transfer Case Speed Sensors, Replace Wiring Harness) #05-04-21-003 - (Jun 27, 2005)
"Service 4WD" Light Illuminated, DTC C0374 Set (Inspect Wiring Harness to Transfer Case Speed Sensors, Replace Wiring Harness)
2004-2005 Buick Rainier
2003-2005 Cadillac Escalade Models
2003-2005 Chevrolet Avalanche, Silverado, Suburban, Tahoe, TrailBlazer, TrailBlazer EXT
2003-2005 GMC Envoy, Envoy XL, Sierra, Yukon, Yukon XL
2003-2004 Oldsmobile Bravada
with Four Wheel Drive or All-Wheel Drive
and Active All-Wheel Drive (RPO NP4) or Active Two-Speed (RPO NP8) Transfer Case
Condition
Some customers may comment on intermittent illumination of the "Service 4WD" light. Upon investigation, the technician may find DTC C0374 set. The customer may also comment on intermittent erratic operation of the 4WD or AWD system after driving through rain/snow or simply going through a car wash.
Cause
The speed sensor signal may have become corrupted. Possible openings in the speed sensor wire insulation (twisted pairs) can allow water intrusion. Also, wire connections contaminated by water may result in short circuits and erroneous speed sensor readings. This most often occurs on the rear speed sensor circuit.
Correction
Inspect the wiring harness to the transfer case speed sensors. On Rainier, TrailBlazer and Envoy models (NP4), fabricate a replacement speed sensor harness between the C101 connector and the speed sensors. Refer to SI Document ID #1454917. Replace the affected twisted pairs. Use service connector pack, P/N 88987183, at the speed sensor end and terminal, P/N 15326267, at C101. Terminal testing tools and service terminals can be found in Terminal Repair Kit J 38125. Do not over twist the two wires in the replacement harness.
The smaller transfer case harness splices into the larger chassis harness a few inches in front of the crossmember. The chassis harness routes along the left side of the frame under the driver door area. Use nylon tie straps to secure the fabricated harness to the main chassis harness between the transfer case and C101.
On the full-size pickup and utility models (NP8), replace the 2.2 m (88 in) pigtail harness that runs from the C151 connector under the hood to the transfer case. Use either harness, P/N 15224661 or 15224663, depending on vehicle equipment. Refer to SI Document ID #1430253.
Important: Technicians should verify the integrity of the splice joints after the repair. All splice joints and connections should seal properly against water or a repeat condition can occur.
Parts Information
Part Number
Description
15224661
Harness Asm-Transfer Case Sel
(4WD Full-Size Pickup/Utility w/NP8 and without Four Wheel Steering (NYS)
15224663
Harness Asm-Transfer Case Sel
(4WD Full-Size Pickup/Utility w/NP8 and Four Wheel Steering (NYS)
88987183
Connector-w/leads, 2-way, Female (Speed Sensor)
(All Vehicles)
Warranty Information
For vehicles repaired under warranty, use:
Labor Operation
Description
Labor Time
N6630
Wiring And/Or Connector-Transmission/Transfer Case/Transaxle/Front and Rear Axle Control - Repair or Replace
Use published labor operation time
GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION
© Copyright General Motors Corporation. All Rights Reserved.
--------------------------------------------------------------------------------
Document ID# 1677268
2003 Chevrolet Chevy K Silverado - 4WD
2003 Chevrolet Chevy K Silverado - 4WD
--------------------------------------------------------------------------------
Service 4WD Light Illuminated, DTC C0374 Set (Inspect Wiring Harness to Transfer Case Speed Sensors, Replace Wiring Harness) #05-04-21-003 - (Jun 27, 2005)
"Service 4WD" Light Illuminated, DTC C0374 Set (Inspect Wiring Harness to Transfer Case Speed Sensors, Replace Wiring Harness)
2004-2005 Buick Rainier
2003-2005 Cadillac Escalade Models
2003-2005 Chevrolet Avalanche, Silverado, Suburban, Tahoe, TrailBlazer, TrailBlazer EXT
2003-2005 GMC Envoy, Envoy XL, Sierra, Yukon, Yukon XL
2003-2004 Oldsmobile Bravada
with Four Wheel Drive or All-Wheel Drive
and Active All-Wheel Drive (RPO NP4) or Active Two-Speed (RPO NP8) Transfer Case
Condition
Some customers may comment on intermittent illumination of the "Service 4WD" light. Upon investigation, the technician may find DTC C0374 set. The customer may also comment on intermittent erratic operation of the 4WD or AWD system after driving through rain/snow or simply going through a car wash.
Cause
The speed sensor signal may have become corrupted. Possible openings in the speed sensor wire insulation (twisted pairs) can allow water intrusion. Also, wire connections contaminated by water may result in short circuits and erroneous speed sensor readings. This most often occurs on the rear speed sensor circuit.
Correction
Inspect the wiring harness to the transfer case speed sensors. On Rainier, TrailBlazer and Envoy models (NP4), fabricate a replacement speed sensor harness between the C101 connector and the speed sensors. Refer to SI Document ID #1454917. Replace the affected twisted pairs. Use service connector pack, P/N 88987183, at the speed sensor end and terminal, P/N 15326267, at C101. Terminal testing tools and service terminals can be found in Terminal Repair Kit J 38125. Do not over twist the two wires in the replacement harness.
The smaller transfer case harness splices into the larger chassis harness a few inches in front of the crossmember. The chassis harness routes along the left side of the frame under the driver door area. Use nylon tie straps to secure the fabricated harness to the main chassis harness between the transfer case and C101.
On the full-size pickup and utility models (NP8), replace the 2.2 m (88 in) pigtail harness that runs from the C151 connector under the hood to the transfer case. Use either harness, P/N 15224661 or 15224663, depending on vehicle equipment. Refer to SI Document ID #1430253.
Important: Technicians should verify the integrity of the splice joints after the repair. All splice joints and connections should seal properly against water or a repeat condition can occur.
Parts Information
Part Number
Description
15224661
Harness Asm-Transfer Case Sel
(4WD Full-Size Pickup/Utility w/NP8 and without Four Wheel Steering (NYS)
15224663
Harness Asm-Transfer Case Sel
(4WD Full-Size Pickup/Utility w/NP8 and Four Wheel Steering (NYS)
88987183
Connector-w/leads, 2-way, Female (Speed Sensor)
(All Vehicles)
Warranty Information
For vehicles repaired under warranty, use:
Labor Operation
Description
Labor Time
N6630
Wiring And/Or Connector-Transmission/Transfer Case/Transaxle/Front and Rear Axle Control - Repair or Replace
Use published labor operation time
GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION
© Copyright General Motors Corporation. All Rights Reserved.
--------------------------------------------------------------------------------
Document ID# 1677268
2003 Chevrolet Chevy K Silverado - 4WD
10-01-2005, 05:47 PM
#15
Document ID# 1341278
2003 Chevrolet Chevy K Silverado - 4WD
--------------------------------------------------------------------------------
Service 4WD Light On, 4WD Inoperative, Diagnostic Trouble Codes (DTC) C0300 and/or C0305 Set (Reprogram Transfer Case Control Module (TCCM)) #03-04-21-005 - (Jun 5, 2003)
Service 4WD Light On, 4WD Inoperative, Diagnostic Trouble Codes (DTC) C0300 and/or C0305 Set (Reprogram Transfer Case Control Module (TCCM))
2003 Chevrolet Avalanche, Silverado, Suburban, Tahoe, TrailBlazer
2003 GMC Envoy, Sierra, Yukon, Yukon XL
2003 Oldsmobile Bravada
with 4WD (RPOs NP4, NP8)
Condition
Some customers may comment that the Service 4WD light is on and/or the 4WD is inoperative.
Cause
Condition may be caused by a TCCM calibration issue.
Correction
Follow the service procedure below for diagnosis and repair of this condition.
With a scan tool, select the TCCM DTCs.
- If TCCM DTCs C0300 or C0305 are present in the TCCM, continue with TCCM reprogramming in Step 2.
- If TCCM DTC C0374 is present with any of the above codes, disregard and clear the DTC and continue with TCCM reprogramming in step 2.
- If TCCM DTC C0374 is present alone with none of the above listed codes, additional diagnosis is required. Refer to Service Information (SI) for proper diagnosis of the applicable vehicle.
- If TCCM DTC C0550 is present, refer to DTC C0550 in SI for proper diagnosis of the applicable vehicle.
Clear all DTCs and reprogram the TCCM with TIS version 3.5 or newer released to the dealers on 3-22-03. Refer to Transfer Case Control Module Reprogramming (SI Document ID #727487).
Warranty Information
For vehicles repaired under warranty, use:
Labor Operation
Description
Labor Time
N8521
Module, Transfer Case Control - Reprogram
0.4 hr
Add:
Diagnosis
0.0-0.3 hr
GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION
© Copyright General Motors Corporation. All Rights Reserved.
--------------------------------------------------------------------------------
Document ID# 1341278
2003 Chevrolet Chevy K Silverado - 4WD
2003 Chevrolet Chevy K Silverado - 4WD
--------------------------------------------------------------------------------
Service 4WD Light On, 4WD Inoperative, Diagnostic Trouble Codes (DTC) C0300 and/or C0305 Set (Reprogram Transfer Case Control Module (TCCM)) #03-04-21-005 - (Jun 5, 2003)
Service 4WD Light On, 4WD Inoperative, Diagnostic Trouble Codes (DTC) C0300 and/or C0305 Set (Reprogram Transfer Case Control Module (TCCM))
2003 Chevrolet Avalanche, Silverado, Suburban, Tahoe, TrailBlazer
2003 GMC Envoy, Sierra, Yukon, Yukon XL
2003 Oldsmobile Bravada
with 4WD (RPOs NP4, NP8)
Condition
Some customers may comment that the Service 4WD light is on and/or the 4WD is inoperative.
Cause
Condition may be caused by a TCCM calibration issue.
Correction
Follow the service procedure below for diagnosis and repair of this condition.
With a scan tool, select the TCCM DTCs.
- If TCCM DTCs C0300 or C0305 are present in the TCCM, continue with TCCM reprogramming in Step 2.
- If TCCM DTC C0374 is present with any of the above codes, disregard and clear the DTC and continue with TCCM reprogramming in step 2.
- If TCCM DTC C0374 is present alone with none of the above listed codes, additional diagnosis is required. Refer to Service Information (SI) for proper diagnosis of the applicable vehicle.
- If TCCM DTC C0550 is present, refer to DTC C0550 in SI for proper diagnosis of the applicable vehicle.
Clear all DTCs and reprogram the TCCM with TIS version 3.5 or newer released to the dealers on 3-22-03. Refer to Transfer Case Control Module Reprogramming (SI Document ID #727487).
Warranty Information
For vehicles repaired under warranty, use:
Labor Operation
Description
Labor Time
N8521
Module, Transfer Case Control - Reprogram
0.4 hr
Add:
Diagnosis
0.0-0.3 hr
GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION
© Copyright General Motors Corporation. All Rights Reserved.
--------------------------------------------------------------------------------
Document ID# 1341278
2003 Chevrolet Chevy K Silverado - 4WD
10-01-2005, 05:48 PM
#16
Document ID# 1054312
2003 Chevrolet Chevy K Silverado - 4WD
--------------------------------------------------------------------------------
Adm Msg - Inoperative 4WD/AWD or Service 4WD Indicator (Admin Number VSS20020131 10/4/02) #VSS20020131 - (Oct 4, 2002)
Adm Msg -- Inoperative 4WD/AWD or Service 4WD Indicator (Admin Number VSS20020131 -- 10/04/02)
Chevrolet Silverado, Tahoe, Suburban, Avalanche, TrailBlazer, TrailBlazer EXT; GMC Sierra, Yukon, Yukon XL, Envoy, Envoy XL; Oldsmobile Bravada
With RPO Codes: NP8 - Autotrack Transfer Case; NP4 - Autotrack Transfer Case; NP1 - Electric Shift Transfer Case
Important
Corporate Bulletin Number 02-04-21-006A will supersede this message.
Customer Concern
Some customers may comment that the service 4WD indicator is on, or the 4WD system is inoperative.
Cause
The Transfer Case Control Module (TCCM) has not received the wake-up call during key-up and has remained in the "sleep mode." When the TCCM is in the "sleep mode," it will not communicate with the class II bus or the Tech 2.
Correction
Remove the underhood TCCM fuse (labeled ATCM or TREC). Wait 30 seconds and then reinstall the fuse. The module should "wake up" and communicate with the Tech 2. Reprogram the TCCM using normal SPS procedures, using operating system calibration number 12580062 (or the most current calibration).
GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION
© Copyright General Motors Corporation. All Rights Reserved.
--------------------------------------------------------------------------------
Document ID# 1054312
2003 Chevrolet Chevy K Silverado - 4WD
2003 Chevrolet Chevy K Silverado - 4WD
--------------------------------------------------------------------------------
Adm Msg - Inoperative 4WD/AWD or Service 4WD Indicator (Admin Number VSS20020131 10/4/02) #VSS20020131 - (Oct 4, 2002)
Adm Msg -- Inoperative 4WD/AWD or Service 4WD Indicator (Admin Number VSS20020131 -- 10/04/02)
Chevrolet Silverado, Tahoe, Suburban, Avalanche, TrailBlazer, TrailBlazer EXT; GMC Sierra, Yukon, Yukon XL, Envoy, Envoy XL; Oldsmobile Bravada
With RPO Codes: NP8 - Autotrack Transfer Case; NP4 - Autotrack Transfer Case; NP1 - Electric Shift Transfer Case
Important
Corporate Bulletin Number 02-04-21-006A will supersede this message.
Customer Concern
Some customers may comment that the service 4WD indicator is on, or the 4WD system is inoperative.
Cause
The Transfer Case Control Module (TCCM) has not received the wake-up call during key-up and has remained in the "sleep mode." When the TCCM is in the "sleep mode," it will not communicate with the class II bus or the Tech 2.
Correction
Remove the underhood TCCM fuse (labeled ATCM or TREC). Wait 30 seconds and then reinstall the fuse. The module should "wake up" and communicate with the Tech 2. Reprogram the TCCM using normal SPS procedures, using operating system calibration number 12580062 (or the most current calibration).
GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION
© Copyright General Motors Corporation. All Rights Reserved.
--------------------------------------------------------------------------------
Document ID# 1054312
2003 Chevrolet Chevy K Silverado - 4WD
10-02-2005, 03:16 PM
#17
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you will have to check for any ATC (transfercase) codes to get the service 4wd codes. they are a different selection from PCM (engine) and won't show up unless you specifically choose the atc. what scanner was autozone using?
01-24-2006, 12:57 PM
#19
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hey guys, i have a very similar problem, except i pulled the code and i think it was a 1026... i cant remember for sure, ill go scan it again in a second.
but i just came across this post from ss1le, and it doesnt look like any of the symptoms are the same as mine...
my S4WD light is on as soon as i start the truck, the code said "No communication with ATC/transfercase
the indicator lights on the 4wd switches are not lighting up (not even the 2wd light)
any ideas on this?
ill go pull the code in a second and post the code if the one i said is incorrect.
thanks alot guys... i hope i fix this before i get any snow here.
but i just came across this post from ss1le, and it doesnt look like any of the symptoms are the same as mine...
my S4WD light is on as soon as i start the truck, the code said "No communication with ATC/transfercase
the indicator lights on the 4wd switches are not lighting up (not even the 2wd light)
any ideas on this?
ill go pull the code in a second and post the code if the one i said is incorrect.
thanks alot guys... i hope i fix this before i get any snow here.
01-24-2006, 04:21 PM
#20
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Location: Minnesota
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just fixed it!!!
i was un aware that the ATC fuse exsisted, i checked the 4WD fuse several times, and it was fine, but after reading this thread, i noticed ATC fuse, so i went to pull it to get the atc out of "sleep mode" as stated above, when i pulled it it was blown!!
i replaced it and i now have 4wd... this made my day as it has been out of service for about three weeks.
any ways, thanks for the link SS1le02.
i was un aware that the ATC fuse exsisted, i checked the 4WD fuse several times, and it was fine, but after reading this thread, i noticed ATC fuse, so i went to pull it to get the atc out of "sleep mode" as stated above, when i pulled it it was blown!!
i replaced it and i now have 4wd... this made my day as it has been out of service for about three weeks.
any ways, thanks for the link SS1le02.
