QuestionHave a 1990 camry 3sfe that we replace the engine in and since then I been frying the ecu's.I've traced wiring for possible damage,ensured identical replacement # of ecu,voltage reads 14.12 at battery when running,currently diag. reads 51 which I believe is switch signal,which switch might this be? Any possible solutions,tired of car quitting every other week,replace ecu and car runs again,last ecu smelled when fried.At wits end,Thanx in advance.
AnswerThis is very difficult to answer without me being able to have the car to check.
The 51 code means nothing it just lets you know that the a/c switch is in the on position.
Since this started after the engine replacement it makes sense that this has everything to do with what is going on.
Needless to say it's no use replacing any more ECUs.
The reason is obvious, there is too much current going through one of the ECU's circuits which is probably caused by a short to ground in a wire in the harness.
About the best advice I can give right now is to disconnect all of the ecu connectors, disconnect the battery and check all the terminals for a direct short to ground with an ohm meter(DVOM) there are a few that should show a ground connection but they are either white/black or brown/black, these are the ECU ground bus connections and they are normal if they show a ground path, any of the other colored wires should not be grounded.
If there is a direct short to ground in any of the wires let me know what color they are, I may have to send you an illustration to help identify the pin connector so include an email address in your reply, contac/t me directly at tedrttr@yahoo.com/ With enough exchange of information I might be able to figure this out.
