With winter and deer season coming I want to get my 4x4 to working properly so I don't get stranded...My 4x4 uses an electronic button to engage from 2 wheel to 4 wheel....When the truck is running the 2wd light/button is illumated, the other two options are 4wd high and low. Most of the time when I press the button to switch to 4wd the lights will cycle through high then low and then back to 2wd and it won't switch over...I can hear the truck trying to switch under the truck as the lights cycle through the different drives....about 1 out of 15 times the 4wd will actually engage and sometimes its in reg drive as far as gears go or I have it in neutral or something else when I'm trying to switch it over....I keep trying different combinations and theres no luck with consistancy...so some days the 4x4 will work a couple times and other days no luck at all...ideas?
Electronic 4x4, What is wrong, How to fix, How to install:
For the newer style electrnic 4x4 systems in vehicles with OBD-II systems and the shift button between the instrument panel and the radio/HVAC control stack:
1) The diagnostic trouble codes are displayed on the three transfer case shift select buttons. The shift select buttons are located on the instrument panel. When the connector pin 13 on the data link cable is grounded, and the ignition switch has been OFF for at least five seconds prior to positioning the ignition switch to run the shift select buttons will blink various times together in order to indicate a diagnostic trouble code from 1 to 4.
2) Position the ignition switch to OFF. Ensure the ignition switch is positioned to OFF for at least 6 seconds.
3) Connect pin 13 on the data link cable to a vehicle ground source. The data link connector is located in the cab under the instrument panel on the drivers side.
4) Position the ignition switch to RUN.
Note the shift select buttons for blinking codes.
If the shift select buttons all blink one time and stop, and do not continue to blink, no fault codes are stored in the TCCM. The transfer case shift select buttons will blink in order to identify any stored DTC. If only one code is stored in the TCCM memory, that code will blink repeatedly with a three second delay between blinking sequences. If more than one code is stored, the first code will blink once, then after a three seconds delay, the next code will blink. This sequence will continue until pin 13 is no longer grounded.
When reading the diagnostic trouble codes, the number of shift select buttons blinks will indicate the code number.
The error codes are:
1 - RAM Standby Power Fault
2 - Encoder Fault
3 - TCCM Motor circuit
4 - Ram/Rom failure
(Diagnostic Trouble Code (DTC) 1)
When the ignition switch is positioned to RUN the TCCM test to determine if RAM standby Power (maintained battery power) to the TCCM was lost since the ignition was last turned OFF. When power is interrupted on pin C6 of the TCCM, the TCCM stores a loss of RAM standby power.
(Diagnostic Trouble Code (DTC) 2)
During electronic shifting, the TCCM check the motor/encoder for normal operation. If the motor/encoder does not function correctly enough times, the TCCM stores a motor/encoder failure DTC 2.
(Diagnostic Trouble Code (DTC) 3)
The TCCM performs a test each time the electronic-shift motor is turned ON or OFF. If the motor does not function properly the TCCM stores a motor circuit failure DTC 3, and the shift select buttons blink in order to inform the driver of a problem.
(Diagnostic Trouble Code (DTC) 4)
Each time the ignition is turned ON, the TCCM tests the memory, the program, and the internal system in order to ensure that the TCCM is operating properly. If the TCCM detects a fault within the TCCM, the TCCM stores a RAM/ROM memory failure (DTC) 4.
When the TCCM is running a diagnostic, and a code 4 is displayed by the shift select buttons, replace the TCCM.
If you have codes 2 or 3 check all the encoder motor connections at the transfer case, if those check out OK, you will probably need a new encoder motor.
If you have code 4, replace the TCCM.
Make sure all connections are good and no corrosion, and then it's either an encoder or TCCM.
Cheap way - To clear the codes and reset the computer, pull the 5 amp TCCM fuse, located at the bottom of the fuse box. Wait at least a half hour, and then replace the fuse. Turn the ignition key to run, wait for the 4x4 lights to blink, and then turn off. Repeat 5 times, and then start the truck.
Good luck and keep us posted, if your having a hard time getting the dTC codes. A Tech2 scanner can also get the DTC codes for your 4wd system.
The other common issue is that the wire harness to the TCCM is corroded and will need to be addressed. The TCCM is located on the passenger side kicker panel, once your remove the panel. Your be able to access the TCCM and inspect the wire harness and leads for corrosion.
How to install the encoder motor:
Lucky way - The only thing that needs to be removed is the encoder motor itself. Tools needed are a 10mm hand wrench and an 8mm and 10mm socket wrench. The 10mm socket will work on the upper and lower bolts, while the regular wrench is needed for the middle bolt. (Tight squeeze!). The 8mm socket is for the electric plug. Remove the bolts and connector, then, just pull and wiggle it out of the truck. Install in reverse order.
Unlucky way - This means the encoder motor did not just wiggle out. Now the front drive shaft will have to be removed at the transfer case. Then, a yolk puller is needed in order to remove the yolk from the transfer case. Once this is done, go back to the directions in lucky way.
