The other night got in the Suburban started up and check engine light comes on check codes and have five; p0740, p0753, p0758, p0785, and p1860. Truck also seems to be in limp mode ie stuck in 2nd or 3rd gear and will not shift. Checked fuse #20(PRNDL, Auto Transmission, Speedometer, Check Gauges, Tell Tale) and am not getting 12 volts to this fuse. Please Help
1997 gmc Suburban 5.7 2wd auto multiple trans codes
- Thread starter tpw26
- Start date
- Jul 22, 2015
- 2,724
Not sure if your '97 Burb is the same as our GMT360s, but when that happens to our trucks,, one of the first things we look at is the ignition switch. On ours, the pink wire is the one that sends 12v signal to the fuse box (#47 in the Aux under-seat box in ours).
If you have the same layout, and don't get 12v at the wire, we recommend an AC Delco replacement - they fail less often than other brands.
There's a few posts on this site detailing how to troubleshoot / replace the switch, as well.
You may have guessed this already, but your transmission itself is most likely fine (except for being in limp-home mode; 3rd is the one gear that doesn't require the 'e'lectronics to operate in.) You may be able to shift manually from 1 and/or 2 until you get this fixed.
If you have the same layout, and don't get 12v at the wire, we recommend an AC Delco replacement - they fail less often than other brands.
There's a few posts on this site detailing how to troubleshoot / replace the switch, as well.
You may have guessed this already, but your transmission itself is most likely fine (except for being in limp-home mode; 3rd is the one gear that doesn't require the 'e'lectronics to operate in.) You may be able to shift manually from 1 and/or 2 until you get this fixed.
In the 97 burb no fuse box under seat on drivers side of dashboard but i will have to check that wire
Mooseman
Moderator
Power not getting to the fuse itself, I'd definitely look at the ignition switch. Beyond that, look for broken wiring. I was only able to find the wiring schematic from the fuse to the trans. Traditionally, the fuses are switched on by the ignition switch.