Charged for changing O2 Sensor which wasn't faulty

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franc123, Apr 26, 10:43am
That is highly suspicious, youre not being told the full story. It begs the question how many of these sensors have been faulty? Engine sensors of any description should not be failing on a 4yo 30k vehicle. If this car is in fact NZ new this repair should be being covered by Mazda regardless of its current warranty status. Its difficult to comment further without knowing that.
nice_lady, Apr 26, 10:44am
I don't get it. The tech analyzed the scan for 3 hours, or RAN the scan for 3 hours?

Either option doesn't sound right.
And you've been charged for this scan so I'd say you're entitled to view the results at the least.
desmodave, Apr 26, 12:56pm
Hang on a mo , ya forgot Hubby says like . No disrespect to petrol head in a skirt like :-) .
nice_lady, Apr 26, 1:07pm
Hubby will comment if he thinks it appropriate.
elect70, Apr 26, 1:13pm
Get a second opinion dealers mechs dont always get it right . Case in point was Holden 3.6 running very rough dealer did timing chains , no better so he went to a local mech who looked up 3.6 faults on line sure enough crank timing was out took trans out & the timing wheel had moved on the crank .fixed it & all good, dealer refunded the labour fees
bigfatmat1, Apr 27, 7:28am
you wouldn't achieve anything by having a printout of the scan as sounds like no fault codes so analyzing data to make a diagnostic. Data can only be a snapshot of at the time. Unless you have a the scan tool you cannot read it. And unless you know alot about cars you wouldn't understand or know what the values are or meant to be. It's also interesting that car does not use a 02 sensor for correction it uses a af sensor. However if the vehicle has not been running correctly this can result in damage to a af sensor. So maybe it needed replacing before the next step in the diagnosis could of been taken. I have replaced alot of faulty 02 sensors that are not the cause of the problem but needed to be replaced before progressing.
kazbanz, Apr 27, 9:27am
or short version-The O2 sensor WAS actually faulty just not the only fault :-)
tygertung, Apr 27, 9:28am
Surely cars have been controlled by computers since early 80s?
kazbanz, Apr 27, 9:29am
And if the o2 sensor WAS faulty-just not the only fault.
kazbanz, Apr 27, 9:31am
If I had to make a guess it would be that the throttle body is also utterly filthy and needs a good scrub out.
vtecintegra, Apr 27, 9:32am
Or an ex-Australia can of worms (there are a few via Singapore too)

Also note that Mazda has now switched to using the international numbering in Japan too (this only happened fairly recently)
bigfatmat1, Apr 27, 10:47am
or the purge valve is stuck. Causing a lean condition
nice_lady, Apr 27, 10:53am
Is still like to know: did the dealership run a 3 hour diagnostic test, or did the technician do 3 hours of analysis on the results of a much shorter test?

Either sounds ridiculous to me.
marte, Apr 27, 3:23pm
Diagnosis might have to start from dead cold to X minutes at full temp.

I doubt if its got a single cause, like one bad sensor, or the one blocked or leaking valve or hose or bad connection.
kazbanz, Apr 28, 4:40am
One question I have is--How long has OP actually owned the car?
im wondering if it has always run on 91 fuel previously
trade4us2, Apr 28, 6:18am
My modern computer controlled car had a lot of weird electrical problems: headlights going off and on by themselves, wipers wiping randomly, blinkers blinking rapidly. A mechanic and two auto electricians could not diagnose the problem, let alone fix it.
I eventually fixed it myself in about ten minutes.
I have given enough information for any competent auto electrician to diagnose the problem. So what was it?
No OBD2 Codes were ever written (there's the biggest clue of all!)
franc123, Apr 28, 9:00am
#67 Given all those systems are likely to be BCM controlled and there is no codes you would have to suspect the BCM is losing power somehow or theres a bad earth connection, or the module itself is playing up. You would eliminate the first two first.
cpnnz, Apr 28, 9:23am
I'd be looking at a sticky fuel pressure regulator which is part of the in-tank fuel pump.
gph1961, Apr 28, 9:51am
enough oxygen has been given to this post
elevoria23c, Apr 28, 1:33pm
running on 95
elevoria23c, Apr 28, 2:00pm
yes you could be right, maybe it should be running on 91
trade4us2, Apr 28, 2:05pm
You are correct. The two earth connections from the BCM computer chip were broken. I soldered them up. I may put a flexible wire in instead.
Why didn't auto electricians check that?
franc123, Apr 28, 2:07pm
Running on either fuel is NOT going to cause any issue so lets forget that one right now.
headcat, Apr 28, 2:39pm
And close to 3 hours labour for others.
headcat, Apr 28, 2:45pm
But was she a 'nice-lady'?