DTC 38 and 41

[frogcity]

94 GMC 1/2 ton 6.5 TD 4wd-posi AT

What do I need to do to correct this problem? New to diesels and auto trans. and I need some steerage in the righ direction. TIA

Forgot to mention that when this happened, I had to replace the brake switch and 2 brake fuses, but I still have these two codes.

[JohnC]

OK, this may be a stupid question, but did you clear the codes after you fixed the switch? If not, they're probably not current. They'll clear themselves after 50 start cycles.

[frogcity]

I cleared the codes after replacing the first fuse, but forgot to after the 2nd fuse and brake switch. Only the standard code 12 now.