92 chevy truck code 12 and code 15

Question

I have a 92 chevy truck that is throwing a code 12 and code 15. When it warms up it stalls and wont start till few hours later.

Answer 1

12 Electronic brake control module malfunction

15 Coolant temperature sensor circuit

Code 15 can also be Electronic brake control module malfuction also,if you have a faulty coolant temperature sensor the engine will still start, and not stall  and start a few hour later. Lets say you have code 15 and this is truly the cause , this mean the engine always sees a low temperature and in return will give more fuel. this in return you will see a rich condition the exhaust outlet will be black smoke. You need to check the basic which is fuel ,spark and air. If the engine stalls when warmed up you need to check fuel pressure, the specification is 9-13 psi.with key on engine off. This type of year vehicle there has been fuel pressure issue cause by the fuel pump pulsator which lead to hard to start and a no start condition TSB # 66-63-09