C0309 Transfercase code

Truck is seting a C0309 code . Service 4wd light is on, no lights on switch are on , truck drives fine in 2wd but will not switch to 4wd. What is the most common cause ? TC Encoder Motor?

Thanks for any help.

Truck is seting a C0309 code . Service 4wd light is on, no lights on switch are on , truck drives fine in 2wd but will not switch to 4wd. What is the most common cause ? TC Encoder Motor?

Thanks for any help.

the reason you haVE NO 4wd is because the encoder motor is shorted .

check the fuses ATC 20 amp is blown I bet !

Thanks . I will check it tomorrow.

ATC 20 fuse is good. Test for C0309 is test motor leads A & B for short to voltage 0 to .2 volts ok . Mine is 0 so next step is change out tc shift control module.

ATC 20 fuse is good. Test for C0309 is test motor leads A & B for short to voltage 0 to .2 volts ok . Mine is 0 so next step is change out tc shift control module.

the transfercase must be set to neutral, this is because the encoder motor is shipped / manufactured in the neutral position ..If this does not go into the neutral position with the 4wd control panel , when you remove the defective encoder, then you must rotate the transfercase key to match the encoder key..with the rear wheels off the ground ,and rotating the drive shaft this can be done with some effort.

replace switch. mine threw service 4wd on 5 000 miles after i bought it from the guy, so it was around 55 000 or so.. matter of fact, i jammed toothpick between 2HI button and switch case, and drove like this, without lights flickering, for quite a bit. then replaced it. was around 60 bucks, 5 minute job, have over 60 000 miles on that aftermarket switch, used it continuously this winter.