>Nothing wrong with my car, >... but the 'check engine' light won't go out >checked "codes" >changed all 4 O2 sensors and light still on>can't pass smog so registration lapses>switch to "non op" registration >I keep driving it for 2 years with old tags waiting for cops to tow it away >go over a speed bump>indicator lamp turns off ... what?!>head immediately to the smog station and it passes smog>register it next day ... and week after the "check engine" light returnsStory I heard to explain this:there is an intermittent error and the car will not clear that error unless you have 40 full "cycles" without the error returning. So an error message from a loose wire that re-appears randomly every 20-30 cycles will l keep re-setting the count so that the check-engine light will never go out. I just randomly went past 40 cycles without the error tripping and that's why light turned out. If anybody solved this problem, please tell me how. I'm wondering if there is a way to click through the 40 "cycles" at once without having to spend an hour driving each time. Thanks.
>>3014486You answered it. Set your meter to continuity and wiggle the wiring for it listening for the beep to drop in and out. Check the pins in the sensor connector. Changing parts is easy, wiring repairs are hard.
Did you just check the codes without clearing them? They don't always reset quickly after you fix the problem.
>>3014486What car what codes, if it's loose wiring then the code will tell you what circuit is affected and then you prod around that circuit like the other guy said. You can't just spoof the monitors either, you gotta go through the song and dance to reset them.
>>3014510>Did you just check the codes without clearing them?This was my first question
>>3014510yes, cleared it repeatedly by removing battery cable overnight, which only restarts the problem because its in a mode where you have to drive it fully in a variety of ways up to 100 miles to cycle it as sufficiently restarted back to normal - but during the break-in period the light would return anyhow. >>3014499but I have no idea which wire/sensor is causing the problem, and I have to check it right when it is flickering the error code to realize it. >>3014514it's just a constant check engine light, codes go back to O2 sensors, which I've replaced but didn't help, meaning its some vague problem with air/fuel/temp - could be throttle body, could be exhaust, could be gas tank, fuel lines, etc ... something that goes on/off but needs 40 times in a row of working perfectly to turn the light off. so even if you fix it, you won't know that you fixed it until you hit 40 times. It's bizarre.
>>3014486i hope you bought a proper odb2 reader, as in a cheap 3$ thing from aliexpress (ideally one which accepts different ecu addresses properly so you can mess around with other stuff)obd2 isnt just for clearing codes you can pull all kinds of live numbers from your vehicle. if you suspect a bad o2 or bad o2 wiring then you can get someone else to drive around and you look at your phone or laptop or whatever live reading of the sensor data and see which one is dropping out.>>3014510idk usa but i think at least some states wont pass smog if monitors arent set, so clearing isn't exactly helpful. it just makes people feel better getting it back from mechanic (for a while)as someone who spent 3-4 years learning a lot of detail about how modern engines work to find out simply the cat was fucked, i feel your pain. (car cost less than even a cheap cat sadly not economical it was a bucket. (still have it, if i win the lottery ill fix it) )
>>3014486The easiest thing you could do right now is clean the wiring harness connectors with contact cleaner.
>>3014520But what are the codes? A lot of codes could be O2 sensor or could be other things. Is it a lean/rich code? Cat efficiency? Upstream/downstream O2 signal low/high?
>>3014528>i think at least some states wont pass smog if monitors arent set, so clearing isn't exactly helpfulThat's correct, but for some cars clearing the codes is necessary for it to set the monitors as ready after a reasonable driving cycle. I made the mistake once of not clearing the codes after a fix, and spent hours trying to go through convoluted driving requirements to get it all to set right. I finally cleared it, and then the monitors all set to ready status after my next normal commute.
where I live the meta is just to let your plates expire or put out of state plates that don't have expiration. they barely enforce and the fine is less than emissions+registration+penalties.
>>3014486>>go over a speed bump>>indicator lamp turns off ... what?!If your engine has an EGR system your EGR valve might be fouled and stuck open or closed. If stuck open it sounds like a vacuum or exhaust leak and will give one of the O2 sensors an incorrect reading.If you remove the EGR valve and clean it with brake cleaner the problem will go away for a month or two, but return eventually.
>>3014530p1283 stored; p1283 pendingu1000 oemp1272 pending; p1283 stored;p0102 stored; p0113 pendingc1130u1000 can communication circuit OEMu1000 can communication system [anti-lock brakes]after changing all the O2 sensors the codes that are left are p1283 stored and p1283 pending, o'reilly veri-scan emission status "yellow" - "some emission monitors have not run their diagnostic testing" That's were I gave up for 2 years until the light magically went out for a couple days and I was able to smog it... but now the light is back on.
>>3014545G35 infiniti has variable camshaft timing, no EGR valve ... already tried cleaning throttle body and MAF Sensor and checking for vacuum leaks (by misting brake cleaner at idle and listening for rev if it was pulled into engine) got no results. tightened fuel lines and all the clamps.
>>3014539that's why I switched to 'non op' - it's not registered so technically it isn't 'expired' and the penalties for driving a car with no-registration are a lot lower than driving one with expired registration. They can tow immediately any car after 6-months of expired registration; but they can't tow a 'non-op' car unless they first ticket and give 3 days to move.
>>3014557Check for leaks in the exhaust manifold, flange gaskets and between the catalytic converter and AF sensor. Are the replacement sensors OEM or aftermarket?
>>3014520Removing the battery cables might not do it - you may have to pull the fuse for the ECU so it resets fully.
>>30145551283 means it thinks it's running lean. So most likely air is getting into the system somewhere past the MAF or you have poor fuel flow(weak pump, though that would typically show other symptoms like poor acceleration). Hitting a bump could have jostled some loose intake piping to temporarily seal the leak, or possibly even MAF wiring/MAF itself may be bad and the bump gave it a tweak. The codes should clear within one drive cycle if the issue is fixed.
>>3014486Get a different fuel knob Turney thing
>>3014486Find hot lead (Ignition "On") at ignition switch.Find CEL bulb in dash.Remove bulb. Install new bulb attached to cheap timer relay and hooked to hot lead.Now when key on, timer relay turns on CEL lamp for a few seconds, then turns it off, simulating correct operation, and persuading fuckwit inspector that all is well with your shitbox.Carry on as usual.
>>3014555>u1000yeah, you have a wiring issue somewhere. check all of the grounds going to the engine block, they corrode fairly often.
>>3014621This would work if smog shops didn't also have scan tools
>>3014675Never had them hook up a scantool if the CEL functioned. Just checked the cap and EVAP system and looked underneath to see if there were still cats installed.
>>3014765What they check varies widely by state.
>>3014768>What they check varies widely by state.I've only dealt with the bullshit in Maricopa County, Arizona.Most of the test stations were pretty shitty. I had one fuckhat break the fuel cap on my 70 Olds by thinking it was a ratchet cap. Another launched a friend's military Dodge truck into the car in front of it trying to dyno it.
