Can anybody tell me if my 04 MX5 Euphonics1.6 has a MAP sensor?
The engine management light has come on this last week so it has been in the garage today and it is showing error code P0107(manifold absolute pressure low input).The garage says that he cannot find the sensor and cannot clear the error code.
The car seems to be running OK but my wife who use,s it the most says a couple of times it has lost power and has to change down and rev the engine to stop it from stalling.
P0107 is a code for the barometric pressure sensor, not the manifold absolute pressure sensor (which it does not have). The barometric pressure sensor is on the drivers side inner wing near the fuse box. It has a 3 wire connector and a rubber tube sticking out from underneath (which should be open to atmostphere). It may say “boost sensor” on it.
It measures atmostpheric pressure and sends a signal to the PCM. Possiable causes of the fault are a faulty sensor, faulty connector, faulty wiring or faulty PCM. If you can get a new sensor cheap enough swapping it will eliminate it if nothing else. I’ve not known one to be faulty before. You really need to check the terminal voltages, is this something that you have the tools and experience to do? You say the fault code won’t clear so it must be a continuous fault so should be easy to pin point. First check really is to check the connector is fully connected and the visually the connectors all look OK.
Check the voltage on each of the wires with the engine at idle. The Light Green/Red wire should have 4.5 - 5.5 volts, the Black/Red wire should have near zero volts and the Blue/Yellow wire should have between 2.1 volts and 4.8 volts (depending on altitude). Check that first.
For info, the code is generated if for whatever reason, the PCM sees the voltage on the Blue/Yellow wire drop below 2.1 volts.
The 5.4v on the blue/yellow seems high. I’m off out now, I’ll comment some more ASAP. It could simply be a faulty sensor from those readings. The feed and ground seem OK. If you can get one cheap enough and quick enough (www.mx5revive.com maybe) it may be worth getting one to rule it out. Having said that, I would think the fault code would clear as the voltage is above 2.1 volts.
With more than 4.8 volts on the Blue/Yellow wire the code P0108 should be stored…
You could really do with checking the voltages at the PCM ends of the wires now. Can you gain access to it? It’s in the passenger footwell but should be protected by shear bolted cover.
No, it should be the same as the reading from the sensor end of the wire. As said, could be a wiring fault… You need to check continuity/resistance of the wire. You said that wire had 5.4 volts in your post on the 27th…
since my first check at the boost plug end i seem to have lost this voltage.when i was connection the boost plug back in with the engine running you could hear the engine pick up for a couple of secounds then settle back to tickover.It is not doing this now when pluging the boost plug in.The voltage reading straight from the ECU on the Yellow/Blue pin without any wires is 0.02volts.I have had an issue with water in the foot well and the plug was wet when i first got to it.
Have you checked for corrosion on the ECU terminals. You should be doing the voltage checks with the sensor plugged in. The Yellow/Blue wire is a signal voltage from the sensor to the ECU there should be no output from the ECU on this wire.
The Yellow/Blue wire had green fur around it at the ecu end.The ECU terminals are all in good condition.Do i need to check the Yellow/Blue wire with both ends pluged in? As in check the voltage with a pin down the back of the connector block at the ECU end with the engine running.
Yes, the voltage should be the same at both ends of the wire with the ignition on and everything plugged in. Green fur is not a good sign… the trouble with that is there may be a high resistance between the terminal in the plug and the terminal on the ECU. The only way to check that is to monitor the voltage the ECU is reading using diagnostic equipment that can read live data from the ECU, PID (Parameter Information Data) monitor in Mazda speak.
You could try some electrical contact cleaner in the terminal if you have any/can get any.