Hi all. I have a 1989 Camaro RS. Check engine light comes on intermittently, usually after rapid acceleration or sustained highway speeds. Outside temp/ humidity/ weather does not seem to affect. I have a cheap little 12 pin code reader I bought off of amazon, and it's giving me the following codes-

43) Low voltage detected to the EST circuit
51) Computer problem/ bad PROM circuit/ ECM/PCM failure
53) System voltage too high/ EGR system fault/ Alternator voltage not normal

If anyone has any ideas what could possibly be causing this combination of symptoms, please let me know. I know the battery and MAP sensor are good, I replaced the MAP and just got the battery checked today. Thanks!

 

Which engine? 43 usually ignition module or ECM. 51 is usually prom and or ECM. I don't remember 53 as being EGR?
Joe

 

I don't know much about the engine, I'm still very much learning, but I believe it to be a LO3 based on the 8th digit of the VIN being E.

As far as what the codes mean, I was just reading off of the little book that came with the code reader.