Another 4WD light flashing problem
#11
07-07-2012, 07:09 PM
Just tested the plug at the axle and I have power coming from the plug. (13.84). I didn't pull the cable out I just examined it and there were no kinks. Should I then pull it out? Do I undo from the nut or do I take the whole housing off. Just assuming the cable is OK then what????
PS thanks for the help so far I greatly appreciate it.
PS thanks for the help so far I greatly appreciate it.
If the solenoid is working and is now able to control the actuator, then there really isn't any need to test its wiring any longer and we need to move on to something else.
I would move down to the switch at the front axle to see if it is opening & closing in response to the cable being moved.I posted two links in my response above.
They're the underlined sections of text.
I would move down to the switch at the front axle to see if it is opening & closing in response to the cable being moved.I posted two links in my response above.
They're the underlined sections of text.
#12
07-07-2012, 07:24 PM
Getting late for me to do much here now almost dark.
I haven't checked the front diff level lately (about a month ago) and it seemed ok. No leaks. If it was to low would this cause this problem? Should I pull the cable as you suggested earlier do I unbolt the whole side with the plug and all??? or just where the cable goes in? If I pull the whole cover off I should also see the fork right. I know on my buddies jeep the fork was shot but the cable looked fine. Any suggestion you have for me to look at tomorrow would be great and appreciated.
I haven't checked the front diff level lately (about a month ago) and it seemed ok. No leaks. If it was to low would this cause this problem? Should I pull the cable as you suggested earlier do I unbolt the whole side with the plug and all??? or just where the cable goes in? If I pull the whole cover off I should also see the fork right. I know on my buddies jeep the fork was shot but the cable looked fine. Any suggestion you have for me to look at tomorrow would be great and appreciated.
#13
07-07-2012, 07:55 PM
The switch is fed +12V by the TCCM. When the cable is pulled, a detent in the housing pushes on the switch & causes it to complete the circuit sending that +12V back to the TCCM. You have verified that you are getting +12V to the switch. To test the switch, use a multimeter to show that it reads open when the cable is slack (pushed into the housing) and closed when the cable is pulled. Or use a test light to show that the output side of the switch gets +12V when the cable is pulled and only when the cable is pulled.
Just undo the 3 bolts that hold the cable housing on and pull it out.
Assuming anything in auto repair is a surefire way to miss something important.
Really, going this far without reading the codes from the TCCM has been somewhat wasteful, but not everyone has access to a scantool capable of bi-directional control of serial bus devices like the TCCM.
Just undo the 3 bolts that hold the cable housing on and pull it out.
Assuming anything in auto repair is a surefire way to miss something important.
Really, going this far without reading the codes from the TCCM has been somewhat wasteful, but not everyone has access to a scantool capable of bi-directional control of serial bus devices like the TCCM.
#14
07-07-2012, 08:20 PM
Just undo the 3 bolts that hold the cable housing on and pull it out. Just got off the phone with a buddy of mine and he said the same.
Assuming anything in auto repair is a surefire way to miss something important. Agreed
Really, going this far without reading the codes from the TCCM has been somewhat wasteful, but not everyone has access to a scantool capable of bi-directional control of serial bus devices like the TCCM.
I had to do the hoses as I picked one up it started falling a part. I dont have a computer, but I saw this manual way. I'm not sure if they mean the 13 pin on the top or the bottom or top. Seems to me it would be the one on top (assuming they mean the ODBII connector).
http://gmcowners.com/gmc-forum/archi...p/t-14184.html
You don't need a reader to get the tccm code. TCCM codes are, 1, 2, 3, 4
Pin 13 is the pin use use to ground to check codes.
If you did indeed ground #13 the 4wd light will blink
Code "1" is "RAM standby power" and is considered normal, may be caused by clearing the codes.
Code "2" is "Encoder fault"
Code "3" is "TCCM motor circuit"
Code "4" is "RAM/ROM failure"
Assuming anything in auto repair is a surefire way to miss something important. Agreed
Really, going this far without reading the codes from the TCCM has been somewhat wasteful, but not everyone has access to a scantool capable of bi-directional control of serial bus devices like the TCCM.
I had to do the hoses as I picked one up it started falling a part. I dont have a computer, but I saw this manual way. I'm not sure if they mean the 13 pin on the top or the bottom or top. Seems to me it would be the one on top (assuming they mean the ODBII connector).
http://gmcowners.com/gmc-forum/archi...p/t-14184.html
You don't need a reader to get the tccm code. TCCM codes are, 1, 2, 3, 4
Pin 13 is the pin use use to ground to check codes.
If you did indeed ground #13 the 4wd light will blink
Code "1" is "RAM standby power" and is considered normal, may be caused by clearing the codes.
Code "2" is "Encoder fault"
Code "3" is "TCCM motor circuit"
Code "4" is "RAM/ROM failure"
#15
07-07-2012, 08:35 PM
Those are the methods/codes for the NP233 transfer case (the same information is available in our Tech Article section and a link to that very thread is in my signature below entitled '96+ NV233 Diagnosis') , not the NP236. You have the Auto4wd (NV236) transfer case which works differently and cannot be accessed the same way.
Please try to listen to what I'm telling you. I don't write all of this stuff to waste your time.
*EDIT* In fact, that thread is full of mixed information given that it shows the NV236 vacuum solenoid yet lists the NV233 codes, never once mentioning anything about the transfer case options, number of buttons, or anything else that would help identify the transfer case being discussed; something that should have been questioned in the first response to the initial post to give the most accurate help necessary.
Also, please use the quote (
) feature when you are quoting other people.
Please try to listen to what I'm telling you. I don't write all of this stuff to waste your time.
*EDIT* In fact, that thread is full of mixed information given that it shows the NV236 vacuum solenoid yet lists the NV233 codes, never once mentioning anything about the transfer case options, number of buttons, or anything else that would help identify the transfer case being discussed; something that should have been questioned in the first response to the initial post to give the most accurate help necessary.
Also, please use the quote (
) feature when you are quoting other people.
#16
07-07-2012, 08:45 PM
OK. Is it still worth taking the TCCM to someone to read? I suppose it would have to be a transmission shop or GM. I will pull off the housing tomorrow and test switch, cant get the TTCM tested at least until Monday.
#17
07-07-2012, 08:51 PM
I'm guessing you cant use a ODBII reader eh, it's some sort of other scanning tool?
#18
07-07-2012, 08:59 PM
The TCCM needs to be in the truck to get it scanned. It is scanned via the DLC (diagnostic or data link connector) under the steering wheel. The bad news is that the act of disconnecting the battery will have erased any stored codes from the TCCM so to set the codes again, you need to attempt to shift from 2HI to any of the other modes.
I would continue through your checks of the switch. Checking the switch can also confirm the health of the cable. If the switch opens & closes properly, then the cable is also functioning properly.
When you get to the point of trying to get it to shift, to aid these shifts, it helps to be moving. Even slight movement helps. Any range shift (high range to low range or vice verse) must be done with the transmission in neutral. So if you want to go from 2HI to 4LO, get the truck moving around 2-4mph, pop the transmission into neutral, and hit 4LO. For any mode shift (2wd to 4wd, 2wd to Auto4wd, 4wd to Auto4wd, or the reverse of these three) you can be in reverse or drive, but do not have any wheels slipping (i.e. all wheels must be spinning at the same rate).
*EDIT* - Just saw your 2nd reply - Please edit your post rather than reply to yourself. Consecutive posting is prohibited by the rules of the forum since you have the ability to edit in what you have left off.
To answer your question, Generic OBD2 readers are not capable of accessing the TCCM. This functionality requires an Enhanced OBD2 scantool that is capable of bi-directional control as I stated earlier; typically costing >$1000 for a standalone unit (>$500 for PC based units). The tools that most autoparts stores have available do not have this functionality.
I would continue through your checks of the switch. Checking the switch can also confirm the health of the cable. If the switch opens & closes properly, then the cable is also functioning properly.
When you get to the point of trying to get it to shift, to aid these shifts, it helps to be moving. Even slight movement helps. Any range shift (high range to low range or vice verse) must be done with the transmission in neutral. So if you want to go from 2HI to 4LO, get the truck moving around 2-4mph, pop the transmission into neutral, and hit 4LO. For any mode shift (2wd to 4wd, 2wd to Auto4wd, 4wd to Auto4wd, or the reverse of these three) you can be in reverse or drive, but do not have any wheels slipping (i.e. all wheels must be spinning at the same rate).
*EDIT* - Just saw your 2nd reply - Please edit your post rather than reply to yourself. Consecutive posting is prohibited by the rules of the forum since you have the ability to edit in what you have left off.
To answer your question, Generic OBD2 readers are not capable of accessing the TCCM. This functionality requires an Enhanced OBD2 scantool that is capable of bi-directional control as I stated earlier; typically costing >$1000 for a standalone unit (>$500 for PC based units). The tools that most autoparts stores have available do not have this functionality.
#19
07-07-2012, 09:04 PM
OK so a garage might be able to read them I might know someone. I will follow through the other tests tomorrow and then ask the Garage to read them for me (I will remember to do that on Monday) Might as well put the battery and holder back in tomorrow since I know the actuator is fine.
Cheers see what I can find tomorrow.
Cheers see what I can find tomorrow.
The TCCM needs to be in the truck to get it scanned. It is scanned via the DLC (diagnostic or data link connector) under the steering wheel. The bad news is that the act of disconnecting the battery will have erased any stored codes from the TCCM so to set the codes again, you need to attempt to shift from 2HI to any of the other modes.
I would continue through your checks of the switch. Checking the switch can also confirm the health of the cable. If the switch opens & closes properly, then the cable is also functioning properly.
When you get to the point of trying to get it to shift, to aid these shifts, it helps to be moving. Even slight movement helps. Any range shift (high range to low range or vice verse) must be done with the transmission in neutral. So if you want to go from 2HI to 4LO, get the truck moving around 2-4mph, pop the transmission into neutral, and hit 4LO. For any mode shift (2wd to 4wd, 2wd to Auto4wd, 4wd to Auto4wd, or the reverse of these three) you can be in reverse or drive, but do not have any wheels slipping (i.e. all wheels must be spinning at the same rate).
I would continue through your checks of the switch. Checking the switch can also confirm the health of the cable. If the switch opens & closes properly, then the cable is also functioning properly.
When you get to the point of trying to get it to shift, to aid these shifts, it helps to be moving. Even slight movement helps. Any range shift (high range to low range or vice verse) must be done with the transmission in neutral. So if you want to go from 2HI to 4LO, get the truck moving around 2-4mph, pop the transmission into neutral, and hit 4LO. For any mode shift (2wd to 4wd, 2wd to Auto4wd, 4wd to Auto4wd, or the reverse of these three) you can be in reverse or drive, but do not have any wheels slipping (i.e. all wheels must be spinning at the same rate).
#20
07-08-2012, 01:14 PM
I removed the 3 bolts, seems difficult to remove the cover, should I loosen up the bolt on the cable first? I loosen off that nut, still cannot pull the plate off more then 1/2 inch. Do I need to disconnect it first at the actuator?
Last edited by greatwhite; 07-08-2012 at 01:56 PM.