help on reading codes
 

the codes i got on my 89 chevy silverdo 5.7 were 1 flash followed by 2 flashes code 12 im assuming. the other was 4 flashes followed by 3 flashes code 43. does anyone know what these codes mean? thanks in advance.

are you sure you got the codes right? code 12 means system pass. The 43 code must be a stored code that is not currently active.....the 43 means ESC circut(Electronic Spark Control).....but I am still confused by the system pass here is a list of codes
12 System Pass
13 Open Oxygen Sensor Circuit
14 Coolant Temperature Sensor (High Temp Indicated)
15 Coolant Temperature Sensor (Low Temp Indicated)
21 Throttle Position Sensor (Signal Voltage High)
22 Throttle Position Sensor (Signal Voltage Low)
23 Manifold Air Temperature (MAT) Low Temp Indicated
24 Vehicle Speed Sensor (VSS) Circuit
25 Manifold Air Temperature (MAT) High Temp Indicated
32 Exhaust Gas Recirculation (EGR) Circuit
33 Manifold Absolute Pressure Sensor Circuit (High Sig.)
34 Manifold Absolute Pressure Sensor Circuit (Low Sig.)
42 Electronic Spark Timing (EST) Circuit
43 Electronic Spark Control (ESC) Circuit
44 Oxygen Sensor Circuit (Lean Exhaust Indicated)
45 Oxygen Sensor Circuit (Rich Exhaust Indicated)
51 Faulty PROM
52 Fuel CALPAK Error or Missing
54 Fuel Pump Circuit (Low Voltage)
55 55 ECM Error

what does system pass mean? as far as i know i read it right i stuck the paper clip in and turned on acc, and got 1 long flash followed by 2 quick flashes. then imediatly after i got 4 quick flashes followed by 3 quick flashes

system pass means that there are no current faults found....the 43 is probably a stored code from an earlier problem

thanks for the help man. one more question though when im driving my truck the SES light comes on for a brief few seconds and then goes right back off it has only happened a few times and im just wondering if that would be the code 43 that is stored thanks in advance.

Got to Autozone and let them flash it for codes and see what their system says. It may be more detailed. Top of that its free.

like RUFFNECK4LYFE said hit up an autozone and have them clear the code for you then check it in a week and see if it came back