I have a 4Dr 4.3 Vortec 2000 Blazer with a 4WD error light on a cold start. With the error light on 4WD will not work and no light appears on the 4WD push buttons. Turning the engine off and restarting will fix the problem until the next cold start. Occasionally the error will appear when driving long distances with the engine running, but the 4WD is still operational then. I am anticipating getting the error codes read later this week. Any ideas what the problem is?

 

codes needed in order to point you in the right direction.

 

Just fixed mine doing the same thing
go get 12' of vacuum hose and replace from the TBI to the vacuum diaphram under the batt. box
get both front tires in the air see if you pull on the cable the diff. lock's up and bout tires turn by hand with the vacuum diaphram off spary the cable with WD 40
also their is a vacuum canaster in the left fender check that line also

good luck

 

I just got the codes read today. There are two error codes recorded.

Code 308 and Code 323

The mechanic that read the codes thought it might poissibly be an electrical problem - possibly the electric motor on the converter. I don't have any diagrams of how the system is supposed to work or trouble shooting guidlines.

 

There is no code 322. There is 323 & 4 which both indicate a problem with the "lock" circuit on the transfer case motor. Code 308 indicates a power problem to the transfer case motor. It could be a problem with the controller, could be a connector problem, wiring or what happened to me. The transfer case motor got corroded where it lays along the case and water got into the encoder. It didn't know where it was moving to. (solved by replacing the transfer case motor).

 

im not too smart when it comes to computer codes and such. does the ob2 for the engine the same way to get codes for the 4wd? my service lights on too and when i hit the button for either 4hi 4low or auto 4wd all that happens is the auto light blinks

 

3D_Illustrator,What proceeded those three numbers? A complete OBD2 trouble code should include a letter and 4 numbers. The letter designates the system that the code. For more information on this, check out the OBD2 index thread link in my signature below.

C0308 - Motor A/B Circuit Low
C0323 - Transfer Case Lock Circuit Low

Since you have posted codes that are listed as valid TCCM codes, I am assuming that you are doing it correctly with an enhanced scanner.

beast1978,
As far as the 4wd system is concerned, it can only be accessed by an enhanced scanner. A typical generic OBD2 scanner will not be able to access the TCCM. TCCM codes should be proceeded by C for chassis. Please try to limit yourself to one thread with your question

 

thanks for your help and sorry for the multiple questions per thread. just trying to fix the truck so its safe for the family and safe to take to the mountain. i wish i had someone here in nj i could get to help since im not that smart. doing the head gasket job made me re-think my abilities!

 

I found that the electric motor that is on the transfer case was corroded because of an electrostatic action of the magnesium case and aluminum of the controller motor. I replaced the motor and fixed the problem. Problem same as RonJon above.

Thanks for the help.

 

well i got the new vacum lines all on and im guessing i have them on the right port on the t by the firewall. service light went out finally but doesnt feel like shes engaging. now when i push a bitton the dash doesnt light up and flash like a christmas tree but it just goes right to auto4wd and wont go into any other. any ideas?