I have a 97 Mazda - 323 S V (BA) - 1.8 i 16V (114 Hp) with a manual 5 speed transmission. While trying to change the oil, I noticed the following connector, with one missing wire on what I think is the transaxel housing:

enter image description here

There is a similar connector on the front driver's side of the transaxel housing ( if that's what it is ). The little red circle is the broken wire, the large yellow circle the "senosr" or whatever it is.

This wire looks like it's been broken a long time, and there's no MIL and last time I connected to the ECU there weren't any error codes present.

I've been looking through the service manual for a similar model ( the 96 Protege ) and so far I haven't been able to find anything. The service manual can be downloaded here.

The section for the transaxel starts on page 394.


Here's a similar looking "sensor" on the front side of the transaxel, next to the driver's side front wheel:

enter image description here

  • Do you reverse/ back up lights work?
    – mikes
    Mar 8, 2015 at 21:33
  • It looks as though it would be a speed sensor, but I cannot find anything which looks like it. I suspect it cannot be your speedometer, as that is probably still working :D Mar 8, 2015 at 22:35
  • @mikes I was thinking that also, but they work, the car just passed inspection a few weeks ago. Other than kinda crappy gas mileage ( 19.7 mpg city ) and some idle issues everything seems to be working. Mar 9, 2015 at 4:44
  • @Paulster2 I added another pic which might help in identification. Mar 9, 2015 at 13:49

1 Answer 1


Since you said the reverse lights are still working, it's not the reverse switch.

This switch signals to the engine computer if you are in a gear or neutral. The computer uses this switch to determine several things, including how to handle engine deceleration during shifting and the idle feedback loop. With 1 wire broken, the computer only ever sees this switch in one state (open), which can cause idle issues (especially approaching a stop). Depending on how the computer handles this it may be using more fuel than it normally would, lowering your MPG.

I had this same issue on a 93 Nissan Sentra. The car would sometimes idle about 300rpm higher than normal and ran rich (too much fuel). Different manufacturer, but same concept.

  • Dude, if fixing this solves my bizarro idle problems, I will give you a medal! Jun 4, 2015 at 17:45
  • One thing I noticed that I always thought was freaky was that allot of times it smokes when I put it in reverse. Jun 4, 2015 at 17:51
  • I wonder if I could just splice the wire to fix it instead of paying to have a new sensor put in. Jun 4, 2015 at 17:52
  • Well my car was just stolen so I guess I'll never find out if your answer is correct or not Jun 5, 2015 at 9:40

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