how to check codes?

[cowboyupdan]

I cant find the threds that tell what pins to jump. thanks guys..

when engine lite goes on it seems like the fuel is being restricted or tranny will not kick down.. started happening after replacing ops and fuel filter.

[CAdiesel]

Assuming you have one of the above years. You jump the A and B terminals. Turn the ignition ON. DO NOT START (crank) ENGINE. "Service Engine Soon" light will blink codes. blink-blink-blink (short pause) blink-blink-blink-blink (longer pause) is a 34. If you get 12 there is nothing to report. If you get anything else post it here and we'll help you out. To clear codes push brake and throttle at same time until SES light blinks 12. Turn key off and remove jumper.
Good Luck.

[cowboyupdan]

thats what i thaught, just wasnt sure. havnt had to check in a while..

so i am throwing a few codes..
29
38
41
78

it is a 94 k2500 chyanne. srw reg cab long bed. the fuel line is leaking near tank and has been for a year. I just changed the OPS and fuel filter and oil change. i had the waste gate wired but loose (i f-ed up). the boost controler was still connected.

so before this tune up i had no codes.. on the way home from tune up the light came on. i reconnected the vac lines to the boost controler and wired the waste gate tighter. but still popping the codes. if i shut truck off and turn back on the light goes off and will drive great till i get on it again through two gears(automatic). feels like fuel is being governed

[cowboyupdan]

ok did some reserch and found a list of codes..

29-glow plug relay fault
38-brake switch stuck off
41-brake switch circuit fault
78-wastegate solenoid fault

my E-brake pedal has a week spring and does not stay up.. will this cause the two brake codes? i do not know much about this brake system because it is not vacume boost.

[grancito]

Waste gate solenoid problem will sometimes cause 29 to appear.

[JD_countryboy]

Did you clear the codes after you rewired wastegate shut? Those codes will stay in memory once they are set. Take a rubberband and use it to hold your parkin brake pedal up. Go from pedal to release hadel. Works like a charm. Then (if you use the parkin brake) the rubberband will simply break and casue you no damage, but not restrict your parkin brake operation.

[cowboyupdan]

i have not cleared the codes before yesterday.. I tried that rubberband trick with zip ties before but now there are also plow controles there to make things difficult. no worrys, i'll get er done. havnt driven sence i cleared codes to see if it still happens niether

[JD_countryboy]

Ok. try clearing the codes, and if they come back, repost them and well try n help some more.

[cowboyupdan]

ok.. cleared codes, tied up e-brake pedal and tried a few times. every time when powering up the on ramp it would trip the ses light at about third gear.

codes..
38 and 78

the stock oil pressure guage reads about 55-60. the temp is running normal.

[grancito]

You have a 94 or 95, (fill in your signature with the vehicle specs, it really helps to work out what your problem is) the 78 with revs up is probably a false over boost signal caused by a valve train problem, see my "pulse in intake thread".

[cowboyupdan]

thanks for your help. i will look into that thread.. it is a 94

[Bazaromcmullen]

Where are the two A-B terminals that need jumped. I have a 94 I just installed a manual waste gate controller. I am boosting 12 psi max. I had it set to boost mak 10 psi then above 75 mph derive engine light comes on. Now I turned boost up slightly more and it comes on around 60 if I jump on the throttle. If I nurse it the light don,t light at all.