Any seasoned Mazda Techs on the board

[1 Wild R/T]

Ain't technology great... "From a guy who's made a living working on the new stuff through the years..."

 

[70 GTX-R]

I would say it’s very hard to diagnose without the correct tools. Definitely need a scan tool with wheel speed data, even better if you can graph it. I would also say it would be important to be able to scan ABS system and trans. That should point in proper direction of diagnosis. Does seem to me to be a ABS fault tho. Not sure about Mazda, I work at a gm dealership, but system can definitely cut power if it thinks it has wheel slipping. From description that it does it on turns, seems like a front wheel harness.

 

[dadsbee]

Before the drive... poking thru the scanner I actually found 7 code situations of modules not talking to each other so reset them all.

Drove the 30 minutes to pick up the Granddaughter, with wife staring at scanner screen and all 4 wheel sensors never skipped a beat.

As we went out our gate however, the traction control and tire pressure light came on. No AT light or trans hit this time.

Drive zero issues and while Wife loaded the kid I did a scan hoping there would only be one code to see where the cascade starts.

Now we're getting somewhere, took a screen shot and cleared this code. On the way back monitored the abs module voltage and a few other things and nothing caught my or her eye.

Stopped for some groceries while I kept car running and then put the PCM voltage on graph (bottom) and alternator (top) for the 3 mile drive home. 1/2 way it does this but flashes no lights nor throws any codes. Time to dig the battery, box and the PCM wiring etc out....

 

[dadsbee]

So I tear out the air box, battery, undo the harness plugs from the PCM. Get the battery box with PCM bolted to it removed and now not sure where I'm headed. PCM is bolted to a plastic battery box, thus it's case certainly isn't the ground source. I guess I have to open up the harness plugs, untape all the wires and inspect the connections & wires. Trying to find a wiring diagram so I at least know which wires possibly are power in.. lol

 

[RemCharger]

Can you loosely put it together enough to run it while wiggling harnesses and watching live data.

 

[kiwigtx]

So I tear out the air box, battery, undo the harness plugs from the PCM. Get the battery box with PCM bolted to it removed and now not sure where I'm headed. PCM is bolted to a plastic battery box, thus it's case certainly isn't the ground source. I guess I have to open up the harness plugs, untape all the wires and inspect the connections & wires. Trying to find a wiring diagram so I at least know which wires possibly are power in.. lol
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Has the car been driven through Fords (river or stream crossings on roads) ? Looks like a lot of dust build-up in the engine compartment. Wondering if there is some contamination going on with a module.

 

[dadsbee]

That's just road sand and brine Roger. Looks like **** but it's actually pretty clean everywhere...

That said... wish I'd maybe started here....one pin down on the fuse box. Could I get this lucky???

 

[kiwigtx]

That's just road sand and brine Roger. Looks like **** but it's actually pretty clean everywhere...

That said... wish I'd maybe started here....one pin down on the fuse box. Could I get this lucky???
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Nice catch...the pin above it looks like it has had a bit of heat also. Worth checking them all out.

 

[dadsbee]

Nice catch...the pin above it looks like it has had a bit of heat also. Worth checking them all out.

Now to figure out how to get the fuse box to snap apart.. so I can make a jumper wire or steal an empty pin if there is one.

 

[1 Wild R/T]

Looks like you've found a likely culprit.. Hopefully that wire is related and not just the dome light..

 

[dadsbee]

After poking a lot of pink wires it goes to the transmission. Might explain the AT issue. It's not the power feed to the PCM but maybe that was a fluke on the graph. Gonna fix this wire and put it all back together again and see what happens. BTW hypodermic needles have more than one use!

 

[1 Wild R/T]

I have hundreds of syringes, probably a dozen different sizes... They have lots of uses.... And that's not counting injecting drugs..

 

[66 Sat]

After reading all 4 pages...they call this progress?
I'm sure the Mazda is a nice car, but I bet they could get it to drive just as nice, quiet and smooth without all this bullshit technology.
Good luck anyway, you're pretty switched on to be understanding this stuff, very impressed.

 

[1 Wild R/T]

After reading all 4 pages...they call this progress?
I'm sure the Mazda is a nice car, but I bet they could get it to drive just as nice, quiet and smooth without all this bullshit technology.
Good luck anyway, you're pretty switched on to be understanding this stuff, very impressed.

Like it or not, this ain't 1965... Technology marches on...

 

[dadsbee]

Doesn't matter the make... they're all like this now. Takes a bit longer to get my brain going these days, but I was building and trouble shooting programmable controllers in the most modern glass bottle plant in the world back in '82 to '85. Then 38 years of injection moulding machines after that ...

Now to put it all back together!

 

[eldubb440]

needles and roach clips....... damn hippies

 

[kiwigtx]

Number 8 fencing wire and chewing gum down this way.

 

[66 Sat]

Like it or not, this ain't 1965... Technology marches on...

Agreed, but I wish the manufacturers were smarter in what technology they choose to include, and what they leave behind. Especially with regards to electronics, sensors etc and how they all interlink.

 

[1 Wild R/T]

Agreed, but I wish the manufacturers were smarter in what technology the choose to include, and what they leave behind. Especially with regards to electronics, sensors etc and how they all interlink.

I agree, the stuff that scares me is when they remove a long trusted mechanical connection & replace it with actuators... Steering & brake systems... Drive by wire throttle.. If the engine doesn't run right or the tranny doesn't shift right you probably be fine... If the steering decides to do something unexpected you might become a statistic on an NTSB report...

Yeah, I know they've been doing it for a number of years now... Doesn't mean I trust it... They've been doing it on Airplanes even longer..... Aircraft budgets are nothing like auto manufacturing budgets & still even with double & triple redundancy they still have failures that kill people... In the automotive world people place wayyyy to much trust in stuff that can & does kill you..

 

[dadsbee]

Well.. back from an hour and a half drive after putting everything back together. That PCM voltage does the zero hit about every 12 minutes like it's supposed to do that. Snowing and **** out side so I got to make sure traction control works... light blinks and it unpowers what ever wheel it needs to to make you go straight. ABS pulses away in a lock up. Drove it like a nut... no warning lights.. no AT light.. no transmission hammer everything working perfect.

I might get a better sleep tonight, but I'll be filling it with gas and driving it half the day tomorrow before the Daughter gets it back with my Granddaughters in the back seat...

Thanks to those that have helped and tried to help. Even if that PCM voltage drop is a Mazda special, it at least got me to start looking for a cause !!!