Sticking between 2hi and auto 4x4

[dolphinsfan1966]

2001 Chevy Blazer LT 4x4

 

my truck seems to have a problem sticking between auto 4x4 and 2 hi, it'll go into auto 4x4 but when i try to get it back into 2 hi, it wants to seem to stick....with both the lights on, 2hi and auto 4x4, and when i turn there's a vibration in the front end, is there anything that can be done about this, or do i just not use auto 4x4.......the only way i can fix it is to take the pos terminal off for a min or so and it seems to reset it

?

 

Thanks

Joseph Stone

[GM-Tech]

You might want to first try checking for codes. Here's how...

 

---------

 

Turn OFF the ignition for 10 seconds.

Connect PIN 13 on the data link cable (DLC) to a ground. The DLC is located in the cab under the instrument panel on the driver's side.

Turn ON the ignition, with the engine OFF.

Observe the transfer case shift control switch select buttons for flashing codes. Refer to Diagnostic Trouble Code (DTC) List .

Important: If the transfer case shift control switch buttons all blink only once and then stop, no fault codes are stored in the transfer case shift control module.

 

 

• When one DTC is stored in memory, that code will blink that number of times followed by a 3 second pause and then repeat.

 

• If more than one code is stored, the first code will blink, followed by a 3 second pause and then the second code will blink.

 

• This sequence will continue until PIN 13 on the DLC is no longer grounded.

 

• If the TCCM will not communicate the presence or absence of DTCs, test the above circuits in Self-Test Step 2. If the circuits are complete, then replace the TCCM. Refer to Transfer Case Shift Control Module Replacement .

[dolphinsfan1966]

I dont need a diagnostic analyzer for this? or do i just use a wire to jumper that to a misc. ground?

 

 

 

You might want to first try checking for codes.  Here's how...

 

---------

 

Turn OFF the ignition for 10 seconds.

Connect PIN 13 on the data link cable (DLC) to a ground. The DLC is located in the cab under the instrument panel on the driver's side.

Turn ON the ignition, with the engine OFF.

Observe the transfer case shift control switch select buttons for flashing codes. Refer to Diagnostic Trouble Code (DTC) List .

Important: If the transfer case shift control switch buttons all blink only once and then stop, no fault codes are stored in the transfer case shift control module.

 

 

  •  When one DTC is stored in memory, that code will blink that number of times followed by a 3 second pause and then repeat. 

 

  •  If more than one code is stored, the first code will blink, followed by a 3 second pause and then the second code will blink. 

 

  •  This sequence will continue until PIN 13 on the DLC is no longer grounded. 

 

  •  If the TCCM will not communicate the presence or absence of DTCs, test the above circuits in Self-Test Step 2. If the circuits are complete, then replace the TCCM. Refer to Transfer Case Shift Control Module Replacement .

 

<{POST_SNAPBACK}>

 

 

[GM-Tech]

I dont  need a diagnostic analyzer for this? or do i just use a wire to jumper that to a misc. ground?

 

That's correct. Just ground that pin as described. There's only 4 possible codes you can get. 1, 2, 3 or 4.

[dolphinsfan1966]

just one more question that i should have gotten out there before, do i need to make the light reappear? "service 4x4" before i do this

 

 

I dont  need a diagnostic analyzer for this? or do i just use a wire to jumper that to a misc. ground?

 

That's correct. Just ground that pin as described. There's only 4 possible codes you can get. 1, 2, 3 or 4.

 

<{POST_SNAPBACK}>

 

 

 

[GM-Tech]

just one more question that i should have gotten out there before, do i need to make the light reappear? "service 4x4" before i do this

 

Shouldn't need to. If you've disconnected the battery to reset it as you described, that *might* have wiped out any codes, but I couldn't say for sure.

 

Give it a try... it doesn't cost anything.