I am going to try and explain the steps that I took to clear the Malfunction Indicator Light that I had on my 2006 Chevrolet Silverado Z71.
I started my truck one morning and noticed as I was backing out of the driveway that a message was running across my DIC. The message read "Service 4WD", at first I thought this may have been something that comes on after a certain amount of time to remind me of service. Upon further research I learned that this was a malfunction of the 4WD system. All of the indicator lights on my pushbutton 4WD switch were out and it wouldn't switch into 4WD.
Through all the research that I read it looked like GM had an issue with the solder joints in the switch. Most people reported resoldering the connections or replacing the switch had cured the problem. I had also read that the Transfer Case Encoder Motor Sensor also has a high failure rate.
I ordered the following parts from gmpartsdirect.com; 15136039/ 4WD switch/ $49, 88962315/ Encoder Motor Sensor/ $61, 12384990/ Gasket/ $6.
This is the pushbutton 4WD switch that I have in my truck.
First step was to remove the dash trim piece around the instrument cluster. Tilt your steering wheel all the way down, place the shift lever in L1 and grab the edge of the bezel and pull out. It takes a little persuading to release and get out of the way just take your time.
Next I used my small screwdriver to lift up the tabs for the switch and pull it out, one at the top and another along the left hand side and it will come out.
After removing the switch unplug the 2 connectors and install your new switch.
*** Now you could try to reflow the solder in the switch but when a new switch only costs $50 it's really not worth screwing with in my opinion. The cold solder issue hasn't truely been reported in several years so I think that issue was solved before my truck was produced. I did take my switch apart and resolder all joints and it made no difference in my situation***
From this point I tried the 4WD and it still didn't work, the lights in the switch would cycle through when I started the truck and then they would all go out. So I had just replaced a switch that was still good.
Next step in my parts changing journey was to change out the Encoder Motor Sensor.
The Encoder Motor Sensor is mounted inside the Transfer Case Shift Motor, this requires removal of the Shift Motor from the transfer case and then disassembling the motor to change out the sensor. The sensor sends a feedback signal to the Transfer Case Control Module (TCCM) telling the TCCM which gear the T-Case is in. Any deviation from the request and action will pop the "Service 4WD" MIL alerting the operator of a problem.
Removal Procedure for transfer case motor/encoder[FONT="]
1. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
2. Remove the transfer case shield.
3. Remove the front drive shaft.
4. Remove the motor/encoder electrical connectors.
[/FONT] [FONT="]5. Remove the motor/encoder mounting bolts.
6. Remove the motor/encoder assembly.
7. [/FONT]Separate the encoder motor assembly from the transfer case and place it on a work bench. [FONT="]
Now it's time to take the shift motor apart.
1. [/FONT]Remove the four screws on the outer perimeter of the encoder motor housing. Important: For proper timing and ease of reassembly, hold the gear in place as your remove the cover from the encoder motor assembly with your thumb or finger.
2. Carefully remove the cover from the encoder motor assembly. The cover has a seal on the bottom side. Place the cover in a position to protect this seal from damage and/or contamination.
Important: DO NOT REMOVE THE SCREWS INDICATED WITH THE (1) IN THE ABOVE ILLUSTRATION.
_________
Splitting the casing:
Important: Observe the location of the punch mark on the large gear in relation to the timing mark on the housing if the transfer case was placed in the 2HI for the NV263 (NP1), or Neutral for the NV246 (NP8). The timing marks should be within one tooth of proper alignment. If not, you must note the timing mark positions for reassembly.
I used a Sharpie as well as the timing marks.
Locate the two shims; one on the small gear and another on the larger gear. Set them aside on a clean surface for reuse. Important: After removing the large gear from the housing, a dark gray phenolic spacer should remain in the casting where the bottom of the large gear resides. Locate this spacer and save for reuse.
Carefully lift the large gear from the housing. The sensor and wiring harness will come with the gear.
Disconnect the wiring from the sensor.
Separate the sensor from the large gear.
Ensure the phenolic spacer is in position in the housing.
Important: The sensor has two (2) keyed areas which must be properly positioned when reassembled. The bottom of the sensor has a positioning pin that must be positioned in the cavity in the housing. The sensor key must be properly positioned over the key way in the large gear. Follow the step by step instructions below for ease of assembly.
1:Carefully position the new encoder sensor to the large gear aligning the key way slots. Just begin the insertion of the keyway over the key. Press the sensor onto the large gear using a ¾ inch deep well socket. This will ensure proper installation of the sensor. Notice: Not using the socket to press the sensor on may result in damage to the sensor.
2: Connect the wiring harness to the sensor. The wiring harness connector wording (TOP) must face up or toward large gear.
3: Position the sensor and gear into the housing with the positioning pin seated in the housing. Align timing marks on the large gear and housing previously mentioned.
4: Reinstall the shims on the small and large gears.
5: Ensure that the wiring harness is properly seated in the housing.
6: Replace the encoder motor cover seal.
7: Reinstall the cover with the four (4) screws.
Tighten
Tighten the two (2) long screws to 3.38 N·m (30 lb in).
Tighten the two (2) short screws to 2.25 N·m (20 lb in).
8: Place the encoder to transfer case gasket into position on the dowel pins in the transfer case.
9: Reinstall the encoder motor assembly to the transfer case.
Tighten
Tighten the bolts in the sequence shown to 20 N·m (15 lb ft).
Reinstall the front drive shaft and skid plates that were removed previously. There is a clamp that holds the dust cover in place on the drive shaft, I did not have a part number for it but I was able to get one at my local parts store. The whole process looks a heck of a lot harder than it was. I would say it took less than an hour to do and I was only out about $130 which would have been what the dealership would charge just to look at it. So I feel like I came out ahead and learned a lot in the process.
When I looked at the old Encoder Sensor it had wear marks in it from sitting in the same place all the time. Since I did this I regularly switch to 4WD to kind of "clean" the sensor. Which is not a bad idea for those of you that have a 4WD and don't use it regularly.
I hope this helps someone down the road, feel free to contact me if you have a similar problem. I'll offer all the help I can.
I started my truck one morning and noticed as I was backing out of the driveway that a message was running across my DIC. The message read "Service 4WD", at first I thought this may have been something that comes on after a certain amount of time to remind me of service. Upon further research I learned that this was a malfunction of the 4WD system. All of the indicator lights on my pushbutton 4WD switch were out and it wouldn't switch into 4WD.
Through all the research that I read it looked like GM had an issue with the solder joints in the switch. Most people reported resoldering the connections or replacing the switch had cured the problem. I had also read that the Transfer Case Encoder Motor Sensor also has a high failure rate.
I ordered the following parts from gmpartsdirect.com; 15136039/ 4WD switch/ $49, 88962315/ Encoder Motor Sensor/ $61, 12384990/ Gasket/ $6.
This is the pushbutton 4WD switch that I have in my truck.
First step was to remove the dash trim piece around the instrument cluster. Tilt your steering wheel all the way down, place the shift lever in L1 and grab the edge of the bezel and pull out. It takes a little persuading to release and get out of the way just take your time.
Next I used my small screwdriver to lift up the tabs for the switch and pull it out, one at the top and another along the left hand side and it will come out.
After removing the switch unplug the 2 connectors and install your new switch.
*** Now you could try to reflow the solder in the switch but when a new switch only costs $50 it's really not worth screwing with in my opinion. The cold solder issue hasn't truely been reported in several years so I think that issue was solved before my truck was produced. I did take my switch apart and resolder all joints and it made no difference in my situation***
From this point I tried the 4WD and it still didn't work, the lights in the switch would cycle through when I started the truck and then they would all go out. So I had just replaced a switch that was still good.
Next step in my parts changing journey was to change out the Encoder Motor Sensor.
The Encoder Motor Sensor is mounted inside the Transfer Case Shift Motor, this requires removal of the Shift Motor from the transfer case and then disassembling the motor to change out the sensor. The sensor sends a feedback signal to the Transfer Case Control Module (TCCM) telling the TCCM which gear the T-Case is in. Any deviation from the request and action will pop the "Service 4WD" MIL alerting the operator of a problem.
Removal Procedure for transfer case motor/encoder[FONT="]
1. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
2. Remove the transfer case shield.
3. Remove the front drive shaft.
4. Remove the motor/encoder electrical connectors.
[/FONT] [FONT="]5. Remove the motor/encoder mounting bolts.
6. Remove the motor/encoder assembly.
7. [/FONT]Separate the encoder motor assembly from the transfer case and place it on a work bench. [FONT="]
Now it's time to take the shift motor apart.
1. [/FONT]Remove the four screws on the outer perimeter of the encoder motor housing. Important: For proper timing and ease of reassembly, hold the gear in place as your remove the cover from the encoder motor assembly with your thumb or finger.
2. Carefully remove the cover from the encoder motor assembly. The cover has a seal on the bottom side. Place the cover in a position to protect this seal from damage and/or contamination.
Important: DO NOT REMOVE THE SCREWS INDICATED WITH THE (1) IN THE ABOVE ILLUSTRATION.
_________
Splitting the casing:
Important: Observe the location of the punch mark on the large gear in relation to the timing mark on the housing if the transfer case was placed in the 2HI for the NV263 (NP1), or Neutral for the NV246 (NP8). The timing marks should be within one tooth of proper alignment. If not, you must note the timing mark positions for reassembly.
I used a Sharpie as well as the timing marks.
Locate the two shims; one on the small gear and another on the larger gear. Set them aside on a clean surface for reuse. Important: After removing the large gear from the housing, a dark gray phenolic spacer should remain in the casting where the bottom of the large gear resides. Locate this spacer and save for reuse.
Carefully lift the large gear from the housing. The sensor and wiring harness will come with the gear.
Disconnect the wiring from the sensor.
Separate the sensor from the large gear.
Ensure the phenolic spacer is in position in the housing.
Important: The sensor has two (2) keyed areas which must be properly positioned when reassembled. The bottom of the sensor has a positioning pin that must be positioned in the cavity in the housing. The sensor key must be properly positioned over the key way in the large gear. Follow the step by step instructions below for ease of assembly.
1:Carefully position the new encoder sensor to the large gear aligning the key way slots. Just begin the insertion of the keyway over the key. Press the sensor onto the large gear using a ¾ inch deep well socket. This will ensure proper installation of the sensor. Notice: Not using the socket to press the sensor on may result in damage to the sensor.
2: Connect the wiring harness to the sensor. The wiring harness connector wording (TOP) must face up or toward large gear.
3: Position the sensor and gear into the housing with the positioning pin seated in the housing. Align timing marks on the large gear and housing previously mentioned.
4: Reinstall the shims on the small and large gears.
5: Ensure that the wiring harness is properly seated in the housing.
6: Replace the encoder motor cover seal.
7: Reinstall the cover with the four (4) screws.
Tighten
Tighten the two (2) long screws to 3.38 N·m (30 lb in).
Tighten the two (2) short screws to 2.25 N·m (20 lb in).
8: Place the encoder to transfer case gasket into position on the dowel pins in the transfer case.
9: Reinstall the encoder motor assembly to the transfer case.
Tighten
Tighten the bolts in the sequence shown to 20 N·m (15 lb ft).
Reinstall the front drive shaft and skid plates that were removed previously. There is a clamp that holds the dust cover in place on the drive shaft, I did not have a part number for it but I was able to get one at my local parts store. The whole process looks a heck of a lot harder than it was. I would say it took less than an hour to do and I was only out about $130 which would have been what the dealership would charge just to look at it. So I feel like I came out ahead and learned a lot in the process.
When I looked at the old Encoder Sensor it had wear marks in it from sitting in the same place all the time. Since I did this I regularly switch to 4WD to kind of "clean" the sensor. Which is not a bad idea for those of you that have a 4WD and don't use it regularly.
I hope this helps someone down the road, feel free to contact me if you have a similar problem. I'll offer all the help I can.
Glad you got it all working right.
