Mk2.5 Diagnostics

[goodwoodmx5]

A friend of mine has just mentioned that the engine check light has come on in his 2005 Mk2.5 1.6. To my surprise, this doesn't have the later OBD II port but uses a diagnostics port similar to that found in a Mk1. There is no diagram or key on the inside of the box and I'm certain the connections are slightly different to a Mk1. Does anyone have a map of a Mk2.5 diagnostics port please?

[Mazda Mender]

They are very similar, bar a couple of things you cannot bridge to test and the flash codes are different, but other than that its all the same, the 2.5 must be an early Y reg i am guessing.
M-m

[Mazda Mender]

viewtopic.php?f=87&t=6629&p=57481&hilit=diagnostic+codes#p57481

https://www.dtcdecode.com/Mazda

M-m

[drumtochty]

So you are saying here Wayne that the very early Mk2.5, 1.6 cars did not have the ODB2 socket at the drivers right knee height. Did the very early Mk2.5, 1.8 cars also miss the ODB2 socket.

[Mazda Mender]

So you are saying here Wayne that the very early Mk2.5, 1.6 cars did not have the ODB2 socket at the drivers right knee height. Did the very early Mk2.5, 1.8 cars also miss the ODB2 socket.

Some early 2.5 versions 1.6 and 1.8 did not have the OBDII system, odd ball carry overs, we have hit a few of these over the years.
M-m

[drumtochty]

Thinking about it, the UK mk2 cars did not have a check engine light, well the ones I have driven!

The Mk2 Miata's do have it, they had ODB2 from about 1997 or so.

Robbie Roadster has advised on the OC forum that all the MK2.5 cars still have the diagnostic read out on the engine bay socket.

Steve has advised the car he has seen does not have the ODB2 socket but has a check engine light.

That suggests that they are missing a socket ODB2 but have the MK2.5 ECU.

That is something I have learned, so a good thread Steve and Wayne.

[Mazda Mender]

"Robbie Roadster has advised on the OC forum that all the MK2.5 cars still have the diagnostic read out on the engine bay socket."

Its very limited on the 2.5's as most of it does nothing, so a waste of time.
The ones without the OBDII sockets need to be read like the MK 2's through the diagnostic port tho.

suggests that they are missing a socket ODB2 but have the MK2.5 ECU.

No not really ,it will be wearing the MK2.5 cosmetics..but the MK2 1.6 ECU, as there is no difference between them any way
M-m

[goodwoodmx5]

Back to this one. The chap concerned is coming back in so I can read his codes. So now I know its an early Mk2.5 1.6 with no OBDII connector. However the old style diagnostics port has no map telling me which connector is which. I'm pretty certain that a car of this age won't have a MEN connector. So while I know that I need to bridge GND to TEN, and then I bridge the led from B+ to...where?

[Mazda Mender]

Should be the same bar the cooling fan test..

20170729_111846.jpg (484.01 KiB) Viewed 1866 times

M-m

[emberto1946]

I have a 1999 Mk 2.5 Sport which is fitted with the 'Diagnostic' port in the engine bay - passenger side. The car has been garaged over the Winter and we took it out last night for a round trip of maybe 20 miles and everything was fine. Beautiful day today so we took the hardtop off and my wife went out in the car. 20 minutes later she was on the phone in distress. Car had suddenly lost power and was getting very very hot. I went and swapped vehicles with her and drove the roadster home. All fine for 5 minutes then suddenly vastly reduced power. Managed to limp home (about 5 miles) with heater on full and top down but temperature was almost max. With no diagnostics available I would welcome any suggestions as where to look first. Vehicle is fully serviced - plugs, oils & filters in last 12 months! Help please!! Mike

[Mazda Mender]

It should be a OBD2 system on your 2.5..the diagnostic port in the bay will not really do much.
Run her on the drive and see if the cooling fan kicks in, but it would be interesting to see what fault codes she throws out.
M-m

[Mazda Mender]

I have a 1999 Mk 2.5 Sport which is fitted with the 'Diagnostic' port in the engine bay - passenger side. The car has been garaged over the Winter and we took it out last night for a round trip of maybe 20 miles and everything was fine. Beautiful day today so we took the hardtop off and my wife went out in the car. 20 minutes later she was on the phone in distress. Car had suddenly lost power and was getting very very hot. I went and swapped vehicles with her and drove the roadster home. All fine for 5 minutes then suddenly vastly reduced power. Managed to limp home (about 5 miles) with heater on full and top down but temperature was almost max. With no diagnostics available I would welcome any suggestions as where to look first. Vehicle is fully serviced - plugs, oils & filters in last 12 months! Help please!! Mike

It's either one or the other..a 1999 is a MK2 not a MK2.5 so faults will be dragged through the diagnostic port in the engine bay..1998- 2001.
MK2.5 was OBD2 from 2001 onwards which was in the cab at the fuse box, the diagnostic port in the engine bay will not give you much if not nothing unless it it is an early cross over as the MK2 changed to the MK2.5 version...and contrary to internet B/S the 1.8 version was not a "cosmetic change" but the 1.6 was.
M-m