[Martin Y]

Assuming your car is stock, it doesn't have a manifold pressure sensor.

I'm not familiar with the tool you're using but I believe it's trying to read OBD1 fault codes but your 1996 car has the later 16-bit ECU which uses OBDII codes.

<having Googled the MX5 Tech website> Have you tried telling the tester you have a Mk.2? I think that might be the answer.

 

[Martin Y]

The tester instructions say it can read Mk.1 and Mk.2 codes, and Mk.2 are OBDII codes. But late model Mk.1 cars are OBDII too. But I'm surprised the instructions don't say this, so I'm not sure what to think about that. I do suspect if you just switch it to read Mk.2/NB codes it'll start to make more sense.

 

[Martin Y]

PS If you wanted to try reading codes with a diagnostic LED tool, the format for the later OBDII models is;

Start with an extra-long flash, then there are four rounds of a long flash followed by 0 to 9 short flashes. Count the short flashes and that gives you a 4-digit number. If there's a second fault code stored then it'll do the next four digits the same way. Eventually it'll start again with the extra long flash and the whole sequence will repeat.

If you take your 4-digit number "xxxx" and Google "Mazda fault code Pxxxx" you should find a description. (Most codes are universal but I think some are proprietary to each brand so it's worth Googling for Mazda codes specifically.)

Hope that helps