stuck in 3rd, no speedo/tach

[psfr311]

hey guys i need some help here

i have a 99 tahoe 5.7 4x4 with 155k.


couple of days ago by speedometer went out along with my tach and my shift selector light. at the same time all that happened my transmission started acting up. does not shift once it is in drive just stays in what feels like 3rd gear. it does shift into park,reverse, neutral.


my SES light also came on at the same time with the following codes:

p0740
p0753
p0758
p0785
p1860


I have checked all the fuses and none were blown.

any ideas?

 

[Gzes]

Its in limp mode. Id get under and check the trans plug. It could be broken. My 96 had that and it ended up being choppy wiring in the steering column. Its probably just the plug for you tho.

 

[SunlitComet]

If you lost all that it is just not in limp mode you lost the power supply that feeds the tranny, speedo, tach and indicator system. Break out a multimeter and probe the out put of fuse #20 on the in-cab fuse block. They are pink wires and there should be two coming off the fuse output. They feed all those components. If no power there and the fuse and terminals are good, then probe the white wire coming from the ignition switch going to that fuse. If nothing there then the switch is the likely component that is fualty because the next wire upstream feeds sevral outputs which, by your description, are working just fine.

 

[psfr311]

problem was a bad ignition switch. replaced it problem solved

 

[SunlitComet]

Cool Beans.