Transmission codes and limp home mode

[99tahoemomma]

Drove my 1999 Tahoe on errands this am. On my last stop home, cranked the car, then noticed the light under the PRND321 wasnt lit, along with the check engine light and the check gages light. Drove home slowly, after reading the forum, it seems like it is in that limp home mode. Got the following codes: P0740, P0753, P0758, P1860. I have read some threads that mentioned checking the transmission fuse first (#20). That appears to be ok. Does this sound like it is the ignition switch that has gone bad?

Thanks!!!

 

[Schurkey]

Drove my 1999 Tahoe on errands this am. On my last stop home, cranked the car, then noticed the light under the PRND321 wasnt lit, along with the check engine light and the check gages light.

Does this mean that the Check Engine and Check Gauges lights are NOT lit?

Drove home slowly, after reading the forum, it seems like it is in that limp home mode. Got the following codes: P0740, P0753, P0758, P1860.

What do those codes represent? Don't make us look them up.

I have read some threads that mentioned checking the transmission fuse first (#20). That appears to be ok. Does this sound like it is the ignition switch that has gone bad?

I'd check the fuses, then connect a scan tool and see what the computer is trying to tell you.

 

[99tahoemomma]

Sorry I wasnt clear before.
P0740 - TCC Circuit Malfunction
P0753 - 1-2 shift solenoid circuit
P0758 - 2-3 shift solenoid circuit
P1860 - TCC PWM Solenoid circuit

Yes, the check engine light and check gages lights are on. The scan tool gave the codes above. All fuses are good.

I have read some previous posts that point to the ignition switch and wanted to see if anyone had gone down that path with success or if I needed to try something else?

 

[618 Syndicate]

Fuse "appears to be okay"? What does that mean? Did you test it? Swap it? Or just look at it?

 

[99tahoemomma]

The fuse was tested and there isnt anything wrong with it.

 

[618 Syndicate]

Which fuse? This sounds exactly what my cateye did last summer. Same codes, 2nd, 3rd, and reverse worked. The 2-3 shift is mechanical, 1-2/3-4 require power.

 

[99tahoemomma]

We tested Fuse 20 (transmission) and the white wire in the ignition switch. No power in the white wire. Just ordered a new switch, hopefully that will fix the problem. Here is the video below:

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I will post again once we get it replaced.

 

[SparkyLU558]

We tested Fuse 20 (transmission) and the white wire in the ignition switch. No power in the white wire. Just ordered a new switch, hopefully that will fix the problem. Here is the video below:

xc_hide_links_from_guests_guests_error_hide_media

I will post again once we get it replaced.

Any luck replacing the ignition switch? My 96 k1500 is having the same issue.

 

[99tahoemomma]

New switch worked!

 

[Loper567]

Anybody else chime in? I have this issue but my gauges, PRNDL etc all work. Trans shifts manually fine and has zero problems. I put a new switch in and it fixed random other problems but not this one.