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Discussion Starter · #1 ·
Morning all

Happy Christmas

Have been trying to pull codes from the ECU this morning by jumpering and then attaching a voltmeter (analogue). Have got everything set up as described in the thread at the top of this forum, but only get a constant 12V showing on the voltmeter.

As far as I am aware from what I have read this should only show for about 4 seconds and then should go off and then the codes (if any are stored) should start coming through.

However, we left it for about a minute before we switched off and we tried the test three or four times without any different results.

We did this with a cold engine, am I right in thinking that some codes are stored whether the engine is up to temp or not? This still wouldn't explain why the 12volt reading should not disappear after four or five seconds though.

If, so does anyone have any idea as to what is going on? I am probably doing something wrong but can't work out what?

:confused:

Duncan
 

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So you are shorting between the TEN and the GND(one on left) and have your meter between B+ and FEN.

Make sure you have no loose strands of wire anywhere as a short from the B+ could do a fair bit of damage.

Leave the ignition off when connecting then turn it on but dont start the car. Then it should flash out the codes.

Remember if you have an immobiliser fitted you might have to turn that off first before you turn the ignition on. (so all dash lights show)
 

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Discussion Starter · #3 ·
Yup, all jumpered correctly and ignition off until connected and then switched on. I did manage to short it once, necessitating replacement of the "METER" fuse.

Have now been for a drive an everything is fine (albeit still with the flat spots in acceleration). I replaced the dizzy cap too this morning.

Still getting constant 12Volts on the voltmeter though when the ignition is switched on, weird.

Duncan
 

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If wired correctly... and you have no pulses/flashes/whatever.... you don't have any fault codes stored. :)

John
 

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But the LED I use doesnt stay on (IE a constant 12V)?? if I get no codes.

It stays on for 4 secs then goes off then nothing else. I dont understand the constant 12V.

Think its diagramme time :confused:
 

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Discussion Starter · #6 ·
Don't worry, all is sorted now. Tried it again and it worked first time. DOH!!!. I must have had it shorted somewhere. Donkey!!

Anyway, after clearing the codes that were stored and going for a blast I now have a nice little error 5.

Thanks for the help guys, but it doesn't look like there is any hope for me.

Duncan:eek:
 

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Thanks for the help guys, but it doesn't look like there is any hope for me.
You must be jesting.... Code 5 eh?

That's the knock sensor... It is situated between the two banks, and has a lead coming from it with a connector.. you will need to locate this, and give it a good clean.. although there are two terminals, one is a shield wire and is earthed. the other white wire goes directly to the ECU. this could be open or short circuit to ground. and would need replacing if broken.
after this, the sensor itself would be the next for replacement.. (the inlet manifold needs to come off) and finally the ECU..

to recap:

check the connector,
check the wires for open/ground
replace the sensor
replace the ECU

My thoughts are the connector just needs a clean.

John
 

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Discussion Starter · #8 ·
Had a cursory glance at it yesterday but I kept burning myself on the hot engine and so couldn't get the connector unfastened from the engine. That will have to wait until I get a moment and the engine is cold.


I managed to get the two halves of the connector apart and probed for a resistance, Mr H, in the big magic book of Probes, MX-6's and 626's says to look for 560 mOhms, but I was getting an open circuit (no resistance).

I suppose this could explain the hesitancy at low revs/mid throttle openings that I am experiancing.

Half way there then.
:)
 

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Dumb question time, whilst we are on the subject.

I gather these error codes can effect the performance of the car? If so is it worth clearing any codes that may be logged? I mean having recently bought the car, and given it a minor service myself, would clearing these codes be a good idea? kinda reset it for me.

Also I understand the process having read it for pulling codes but whats a CEL? where do i find it? I need to watch it flash apparently..lol


Marty
 

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Discussion Starter · #10 ·
When I first pulled the codes there were loads of them (about 8 or 9). I then diconnected the battery and put my foot on the brake pedal to dicharge any capacitance.

After reconnecting the battery I for a blast to get the car up to temp, and it did seem to pull a bit better until it was warm and then error 5 must have cropped up and retarded the timing again.

Basically, it will reset the ECU to normal running (therfore more powerful if you had codes showing) but as soon as the codes come back everything goes to sh*t again.

The CEL (Check Engine Light) doesn't exist on my 6, can't comment for the post '95 versions though. Probes get one, but hey, we get the looks.

Our only methods for pulling the codes are either to use an LED rigged up to jumper between the terminals or to use an analogue voltmeter (not digital). Dead easy, even I could nearly do [email protected]

Duncan
 

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In the States, you normally get a CEL (check engine light) on the dashboard.. if you don't have one, or have a diagnostic box, then there may be no way of testing it. ask on 1st gen forum.

John
 
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