My SES light just turned off by itself the other day. I know when you mnually reset it the car must be driven a certain amount of miles before the system will show "READY" but is this the case when it automatically shuts off? Or can I get it inspected before it happens to pop on again?
SES turned off by itself, can I get inspected?
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Yes, you can still get it inspected. Anytime it throws a code it gets stored even if it clears, its still in the 'memory'.
With an intermittent SES light, you likely have a problem which needs to be addressed prior to inspection.
The SES light turning off by itself will not automatically reset the system monitors like clearing the codes will. That said, without knowing why the SES was on to begin with, one or more monitors could potentially be in the "not ready" state. Regardless of the readiness monitors though, you will almost certainly still have stored DTCs. Depending on your local inspection regulations, this could be enough to fail you. Your best bet would be to have all codes reset and then drive for a few days (100-200 miles) to allow the monitors time to reset. If you really want to know what's going on, you could invest in an OBDII tool which reads/clears codes and reports the status of the readiness monitors.
The SES light turning off by itself will not automatically reset the system monitors like clearing the codes will. That said, without knowing why the SES was on to begin with, one or more monitors could potentially be in the "not ready" state. Regardless of the readiness monitors though, you will almost certainly still have stored DTCs. Depending on your local inspection regulations, this could be enough to fail you. Your best bet would be to have all codes reset and then drive for a few days (100-200 miles) to allow the monitors time to reset. If you really want to know what's going on, you could invest in an OBDII tool which reads/clears codes and reports the status of the readiness monitors.
I have a peak tool and I get "o2 sensor adaption limitation" in all cylinders and it's a battle that's been going in for 2 years. Ive spent so much money trying to trigger it, maf, o2 sensors, disa, air intake, vacuum leak checks, and it still comes on. It's just that code. If I can't find a place to let it slide.... Im just f'd.
You need to read up about the exact rules that apply in your state. I know the rules in detail for Illinois now, after a very painful 6-months episode of being unable to pass last year. At least in IL, you must have NO MIL, and no more than one readiness monitor in "not ready" status. More stringent rules apply upon a recheck after rejection due to readiness monitors. I sure had no MIL/CES on when my car was rejected ("rejected" is different from "failed" in IL).
Btw, I have had the O2 sensor adaptation limit E3/E4 for several years, on and off. I know the pain. Currently under control, though.
Btw, I have had the O2 sensor adaptation limit E3/E4 for several years, on and off. I know the pain. Currently under control, though.
DTCs don't directly impact the readiness monitors. Getting the readiness monitors to the "ready" state requires the successful completion of a certain drive cycle during which time the readings from numerous emissions related sensors are monitored to make sure they are within acceptable ranges. If you have problems with O2 sensors, cats, SAP, etc then these problems may prevent one or more of the monitors from being able to enter the "ready" state. In your case, because your codes are on again off again, it's a total crap shoot as to what state your readiness monitors might be in at any given point in time. Either buy/borrow a tool to see for yourself or take your chances with the inspection.
In the end, there were three factors that initially made me scratch my head over the data I saw: First, I a bad MAF. It read low, causing the car to think there is less air than there really was, so the computer dialed the fuel back accordingly, which caused an overly lean mixture. The oxygen sensors detect too much oxygen in the exhaust and tell the computer to inject more fuel. That's the fuel trim number. There is a short term fuel trim, which normally fluctuates quite a bit depending on load, etc. Then there is long term fuel trim, which should be close to 0. I had consistently +12% long term fuel trim, and sometimes +20% short term. Both of them max out at some point, giving you E3/E4. I don't know the threshold for the MIL, but it must be much higher than the threshold for the internal E3/E4, which I am getting a lot without having had the MIL in a loooong time.
Secondly, I had vacuum leaks in several locations (all on the supercharger vacuum lines and connectors, so I cannot comment on where that happens most likely with N/A cars - search, there is a lot of info out here).
Thirdly, I had a clogged fuel filter (about 70k on it) that contributed to fuel starvation.
You need to get the fuel trim values, so you know if you are lean or rich. Once you get the MIL, the P-code will tell you, but before that happens, you probably need some scan tool/software. Then, consider this: The malcondition (rich/lean) may actually physically be present, which means either too little fuel (e.g. clogged injectors?) and/or too much air (usually extra air sucked in via vacuum leaks after the MAF) for lean, or reverse for rich. On the other hand, the fuel/air mixture might in fact be right, but the oxygen sensors are bad and fool the computer (and you) into thinking the fuel trim needs to be adjusted.
Vacuum is strongest in idle, so if you have a vacuum leak, you should see the short term fuel trim be highest in idle, and diminish if you give it some gas. Can do that in neutral, on your driveway. If the lean condition sets in only under heavy load, you may suspect fuel starvation (e.g. clogged fuel filter or injectors). I had some of both, really confusing, but when I fixed the three issues I had one by one, the fuel trim numbers showed the effect each time quite nicely.
I am using Digimoto software with the ELM interface they sell on their web site. Search on diagnostic tools, and you'll get many (sometimes quite strong)opinions on what is good and what is better....
Check out the Wells Engine Management Newsletters (free on the web). You'll learn a lot about this kind of stuff.
Btw, I searched a lot and did not find a reliable way to diagnose the MAF. Really impossible to tell if it's good or bad. Someone on here posted all sorts of resistances he measured, concluding one way or the other. I tried that and got totally different numbers, for both the good and the bad MAF.
Also, I did the fuel flow rate test that's described in Bentleys, and got about 1/3 of the flow they said I should be getting. That prompted me to replace the fuel filter. However, with the new filter I got the same numbers. Go figure. Anyway, replacement of the fuel filter brought the fuel trim numbers down noticeably.
Secondly, I had vacuum leaks in several locations (all on the supercharger vacuum lines and connectors, so I cannot comment on where that happens most likely with N/A cars - search, there is a lot of info out here).
Thirdly, I had a clogged fuel filter (about 70k on it) that contributed to fuel starvation.
You need to get the fuel trim values, so you know if you are lean or rich. Once you get the MIL, the P-code will tell you, but before that happens, you probably need some scan tool/software. Then, consider this: The malcondition (rich/lean) may actually physically be present, which means either too little fuel (e.g. clogged injectors?) and/or too much air (usually extra air sucked in via vacuum leaks after the MAF) for lean, or reverse for rich. On the other hand, the fuel/air mixture might in fact be right, but the oxygen sensors are bad and fool the computer (and you) into thinking the fuel trim needs to be adjusted.
Vacuum is strongest in idle, so if you have a vacuum leak, you should see the short term fuel trim be highest in idle, and diminish if you give it some gas. Can do that in neutral, on your driveway. If the lean condition sets in only under heavy load, you may suspect fuel starvation (e.g. clogged fuel filter or injectors). I had some of both, really confusing, but when I fixed the three issues I had one by one, the fuel trim numbers showed the effect each time quite nicely.
I am using Digimoto software with the ELM interface they sell on their web site. Search on diagnostic tools, and you'll get many (sometimes quite strong)opinions on what is good and what is better....
Check out the Wells Engine Management Newsletters (free on the web). You'll learn a lot about this kind of stuff.
Btw, I searched a lot and did not find a reliable way to diagnose the MAF. Really impossible to tell if it's good or bad. Someone on here posted all sorts of resistances he measured, concluding one way or the other. I tried that and got totally different numbers, for both the good and the bad MAF.
Also, I did the fuel flow rate test that's described in Bentleys, and got about 1/3 of the flow they said I should be getting. That prompted me to replace the fuel filter. However, with the new filter I got the same numbers. Go figure. Anyway, replacement of the fuel filter brought the fuel trim numbers down noticeably.
Laws in your area might be more lenient than where I am but I predict you will fail based on the presence of codes for fuel mixture problems. If you just happen to be running lean, the readiness monitors will probably be fine but you will still fail on the stored codes. Just fix the problem and then you won't have to worry about the inspection.I'll just give it a try I suppose
By my experience, the readiness monitors do NOT go to "not ready" just because a code gets thrown or the MIL/SES come on. Only when you clear any codes do they reset to "not ready", and then they normally come back to "ready" by themselves one by one after some normal driving or after you do the drive cycle. At that point, if you have the oxygen sensor adaptation limit error, some monitors probably won't come back to ready unless you fix the problem. But if you have not cleared any codes yet, you might still be OK monitor-wise, even with the E3/E4 code. Check it out and read up about the regulation in your state. I know that an error code without the MIL on does not cause you to fail the emissions test in IL as long no more than one (any one) of the monitors is "not ready".
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