93 honda civic map sensor

The map sensor circuit appears to be very simple; 3-wire sensor = power, ground, and signal. With your electrical testing, you have concluded that you have an open in the circuit and that the open affects all wires to the map sensor. The open may appear as a loose connection, corrosion, cut or disconnected wire. Trace the wires to the best of your ability to locate the open. Once you locate the open, perform the appropriate wire repair. If unable to locate the open, you have two options: pull the entire MAP sensor harness to the ECM or run your own wires directly from the ECM to the map sensor.

*DO NOT APPLY YOUR OWN POWER TO THIS CIRCUIT (i.e. ohm testing for continuity) BEFORE ISOLATING THE MAP SENSOR FROM THE ECM AS YOU COULD FRY THE COMPUTER!!!

The following schematic shows the simplicity of the circuit; however, fails to identify which wires do what.

Be advised that you may not get a reference or signal voltage unless the key is in ‘RUN’ or the engine in actually running.

https://www.youtube.com/watch?v=iE1ORHc4r7c

I would test a known good working honda to identify what wires are performing a particular function, or call up the honda dealer. Or, maybe someone on this forum my know… even Mr. Car Guy could chime in here as a Honda guru. 🙂

I would lean away from a ECM failure as all other computer controlled components are functioning properly… but all things are possible in the world of automotive.

That said, test for reference voltage directly from the ECM to rule out this possibility.

Honda MAP sensors hardly ever go bad, same goes for the PCM’s. If however your engine is running poorly, it can set a MAP sensor code. If you’re experiencing engine performance problems, I would address those first and then check to see if the code returns. More info on that here.

http://www.ericthecarguy.com/faq/solving-automotive-performance-issues

It could also be a wiring or connector problem as pointed out but only as a last resort would I look to the PCM for a problem.