If you needed to replace a airflow meter in your car (2006 mazda6) and it had STOPPED the car while driving because your partner kept driving it for weeks after the warning light came on, and reset of the warning light didn't work before new sensor went in, am I right in thinking the computer in the car needs to be reset before the car will run? Or should it just start and run fine?
bigfatmat1,
Jan 8, 11:41pm
It will run but will be a fault code from old sensor that will need to be cleared. Just so it doesn't add confusion for future diagnostics.
kazbanz,
Jan 9, 2:14am
Likely any of the real tradies will disagree with me but if its that bad and its ONLY the AFM faulty I would leave the battery disconnected overnight. let the car "forget" all learned settings.
mechnificent,
Jan 9, 3:45am
If the airflow meter is the only fault we'd expect it to start and run.
mechnificent,
Jan 9, 5:43am
Do you know what the exact code was ?
sagenthyme,
Jan 9, 10:25pm
I wish he had written down but he didn't. His auto sparkie mate is away on holiday so I just have to wait till he is back to get them. But the AFM didn't work.
intrade,
Jan 9, 10:47pm
basically a mass airflow code is set due to no signal. The problem can then be the mass airflow component. The wire broken from or to computer mass-airflow or the computer internally is faulting. The newer a car the more probabilistic when your shorted tailgate wire sets a mass airflow code and plenty of U codes a U code is basically a You-code blaming anyone else on the network . because its now nut just a direct link and you can go and spend loads of time to find the real fault like a broken shorted wire in your tailgate. 2006 should be not as complex as the last part of this post. But 2005 is entering the zone of danger and expensive repairs.
mechnificent,
Jan 9, 11:52pm
Lol. What Intrade's saying is that it could be a broken wire, or a fault in the computer, or another fault such as an air leak into the intake or if the internet is to be believer, a throttle position sensor or an engine rev reading not coinciding with what the computer calculates the revs should be for the air flow reading. The code is only an indication of what the computer is reading or calculating, and needs tests doing to confirm what the problem really is before putting new parts on.
franc123,
Jan 10, 11:56am
Well you could try but in a DIY situation I would just disconnect the battery for an hour or so and then see what happens. If I was doing it I would just clear the code and then perform what is known as a fuel trim reset prior to road testing it again and watching what the airflow data and fuel trims are doing. You should get a pretty good indication fairly quick that it's fixed the issue. The other thing I'd be doing is getting a new partner and or converting them into a fulltime pedestrian if they cannot operate a motor vehicle properly.
franc123,
Jan 10, 12:05pm
What he is saying is gobbledygook as usual. Unless a component within the tailgate is on the high speed CAN network it is extraordinarily unlikely to cause any sort of an engine management fault. MAF sensor codes are set for all sorts of reasons other than a lack of output voltage on the signal circuit
kazbanz,
Jan 11, 1:39am
I THINK he is trying to say -don't rule out busted wire etc. My thinking re MAF and disconnecting the battery is that the computer would likely have been compensating for the info provided by the MAF. letting it go back to factory default lets it relearn. -or am I screwed up in my thinking?
franc123,
Jan 11, 3:41am
Yep that's right. Resetting it just speeds up the process a bit.
mechnificent,
Jan 11, 5:31am
long term trim which compensates for wear and/or consistent short term trim adjustments, gets stored in rom so it will be the same every time you restart. Short term trim such as temporary fuel adjustments gets stored in ram and gets reset. Disconnecting the battery doesn't always cure problems. depends on the programing in the ecu.
dirty air cleaner will change fueltrim readings and so will wrong reporting mass airflow meter. Fueltrim is difficult to understand in practice because its like spongebob- opposite days. Thats how i remember how fueltrims work. like on a holden berina map only i found a drity air cleaner with 8% correction on fueltrim. the job of the short therm as in the english language "short therm" is correcting the "long therm" to try and keep the long therm at 0 percent correction +-2 = 100% good on fueling for the catalisator. Its all only existing for emission reasons 14.7 parts air to 1 part fuel . without cat it would be better to run 16 parts air and 1 part fuel but that would nuke a catalysator as you seen on toyotas from 1980s and 90s. emission laws is where almost all expensive problems originate from. and its why vw did just only run full emissions. when testing was detected AKA diesel scandal B$ by the knotheads in California.
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