Reply With QuoteThe fact that it (the light coming) appears to correlate with filling up suggests a problem with the evaporative emissions system. You may just need a new gas cap....Originally Posted by bikerlbf406
'97 Expxplorer Check Engine Light
My check engline light just recently came on. I had it checked at autozone & its coming up with code PO153, which is coming up w/ possible causes of oxygen sensor, fuel system running too rich or lean, engine misfire, or fuel pressure high or low. About a month ago, my check engine light came on for the very same code right after getting gas, and in a couple of days it went off by itself. Now it came back on & once again it was pretty much after getting gas again. This time the gas came from a different station. Any ideas what is like wrong & how to remedy this. The explorer still runs & drives great, so i doubt its engine misfire or anything like that.
Tim, proud owner of 2001 Chevrolet Silverado 1500 & 2007 Honda CMX250C Rebel
The fact that it (the light coming) appears to correlate with filling up suggests a problem with the evaporative emissions system. You may just need a new gas cap....
I concur. Sounds right.
"Tutto nello Stato, niente al di fuori dello Stato, nulla contro lo Stato " -Mussolini
All within the state, nothing outside the state, nothing against the state.
See here.
-Don- SF, CA
I don't concur!
OBD2 code P0153 has nothing to do with gas caps.
-Don- SSF, CA
I tried looking up the code in all data, but lost patients. My reasoning behind agreeing with the gas cap being the culprit is the fact that this occurs at gas refill intervals.
Additionally, I've seen a lot of times just because a code comes from a certain sensor reading out of range variables does not necessarily mean that sensor is the problem.
It's just reading the results caused by the problem.
I'm not saying it's not the problem though. It very well could be the O2.
"Tutto nello Stato, niente al di fuori dello Stato, nulla contro lo Stato " -Mussolini
All within the state, nothing outside the state, nothing against the state.
Well once again the light went off on its own. Just like last time it went off right about the time I get down to 3/4 of a tank. I wonder if its the gas cap or not, cuz if the cap was bad, wouldn't it stay on?
Tim, proud owner of 2001 Chevrolet Silverado 1500 & 2007 Honda CMX250C Rebel
If it were the gas cap, you would get a different code than P0153. See here for OBD2 gas cap code which is P0442, NEVER PO153.
OBD2 systems don't get confused. Say after me, "It's NOT the gas cap and it has nothing to do with the gas cap!"
There can be countless reasons why the MIL goes off and on. Most likely it has to do with how many times you restart the engine. Different OBD2 codes have different criteria for turning off and on the MIL light and often has NOTHING to do with when the problem really comes and goes. For an example, some codes are not set until the car is started three times with the same problem each time. And will clear if there's ten starts without the problem (or whatever number). This is why the factory service manuals are needed these days. They will tell the exact conditions required for the MIL code to come and clear.
For an example, when I had my Ford problem with secondary air injection, it took two starts (after code is cleared by me) in a row with the air pump not working to get an MIL indication. Often a one time problem is ignored and won't set a MIL (Malfunction Indicator Light or "check engine light"). It seemed to me, at first, it only happened after a drive to Reno downtown and after two miles on the way back. But the truth was, I would clear the code at my Reno home, drive to downtown Reno (no MIL) and then on the way home I would get the check engine light. It had nothing to do with the distance, it had to do with driving two miles after the second restart of the engine after the code was cleared. But it seemed the code came on at the same place on the way home from downtown Reno each time, which really had nothing to do with it.
As I have said many times here, do NOT guess an OBD2 code. It's telling you what's wrong. Believe it. It is not making a mistake. It is NOT the gas cap, but it might have something to do with how many restarts or the distance to the gas station after starting and countless other such things that can add to the confusion until you read the factory service manual and see what conditions set the code. But regardless of the conditions for the MIL, the problem is related to what the code says it is, which is NOT the gas cap in your case.
-Don- SSF, CA
With that being said, how do i go about setting to find which is the problem. Afterall the O2 sensor isn't the only thing that could cause me to get PO153.
Tim, proud owner of 2001 Chevrolet Silverado 1500 & 2007 Honda CMX250C Rebel
That's right.
The best I can do for you is to look up the code in my 1997 Ford Mustang factory service manual and post the procedure (and the conditions required for you to get the MIL) in the next couple of days when I am back in Reno (where my 99 Mustang and books are).
I would bet on either a lose connection on one of the 02 sensors or one or more of the 02 sensors themselves if they have more than about 50,000 miles on them. If they are all old, I would replace all four.
Yeah, your vehicle might have four 02 sensors. Which engine do you have? If you have two catalytic converters, you most likely have an 02 sensor before and after each one.
For now, look for something obvious, such as an exhaust leak or a poor connection to an 02 sensor.
You have to get under the vehicle and check things.
-Don- SF, CA
Thanks Don. I have the 4.0L V6 in it. As far as I know it only has once catalytic converter & has 2 O2 sensors. I'll have to see about getting underneath the vehicle & checking things out.
Tim, proud owner of 2001 Chevrolet Silverado 1500 & 2007 Honda CMX250C Rebel
PO153 is a slow o2 sensor, bank 2 sensor 1. That's the front sensor on the driver's side. On a 12 year old truck I'd recommend changing both front sensors.
Bill
Hi Bill,
Welcome to the site - and thanks for posting this reply. I think Tim'll be very appreciative!
Been having login problems. But I am at Reno now and here's how code P0153 sets a MIL.
1. The time since closed loop mode enabled is more than 100 seconds.
2. The average lean to rich response time, from 300 MV to more than 600 MV is over 125 ms.
3. The average rich to lean response time from 600MV to less than 300 MV is more than 125 MS.
4. The VCM ( Vehicle Control Module) turns on the MIL (check engine light) after the SECOND failure.
Conditions for clearing the MIL (besides clearing it all with your OBD2 code reader!)
Three consecutive drive trips without the problem. Code stays in memory without the MIL.
40 warm up cycles will clear the history of the error. A warm up is when the coolant raises 40F (22C) after a cold start.
Now that I have said all that, if you do not find anything obviously wrong, replace your O2 sensor. I would replace both, but it's the one on bank 2, sensor one (main sensor on the engine side of the CV) that's setting your PO153 code.
-Don- Reno, NV
Hey Don - glad you're back in; I only just squeezed back in here myself!
Yeah, but now I look like a FNG here! This is only my second message. Do you have any idea what went wrong?
-Don- Reno, NV
Before I go replacing the O2 sensor I have one question. Wouldn't a bad sensor keep sending the the code to the computer, causing the MIL to stay lit? Seeing what Don said on the MIL light being set off, it just goes to show me that it is a fuel up causing the light to come on, as it will come on after 2-3 times of starting up after a fuel up. If it was a sensor bad, why is it only showing bad after a fuel up?
Tim, proud owner of 2001 Chevrolet Silverado 1500 & 2007 Honda CMX250C Rebel
Not a clue.
For 24 hours I could not even load the page. Dom thinks my ISP (or server) or Host (or whatever the "F" it is) was ID'ing me as a hacker and locking me out.
May be due to asshole spammers. We have been getting hit almost once a day lately and I have to ban/delete these bastards and their ?#@!$$$ posts for "Buy Viagra! Cheapest prices!"... does anyone ever pay attention to this crap? Why do they even bother?
I'd like to have them killed though, still. Just on general principles...
More than likely, whatever is causing your code is an intermittent problem. Most likely, the O2 sensor is on the edge where it sometimes meets spec and sometimes does not. And your MIL will NOT show exactly when it does and doesn't, because certain conditions must be met to light up the MIL.
I don't buy that filling up the tank has anything to do with a P0153 code setting. Hasn't it ever gone on at other times? But as I showed in the previous message, there are many possible variables for setting the code as well as for it clearing.
I think it's just been a coincidence that it has been coming on after a fuel stop, assuming you read the code correctly! BTW, have you checked for new codes lately? Don't be surprised if you have more than one code in memory now and the other is related to your gas cap!
I would recheck for your codes and see if you still ONLY have P0153.
-Don- SSF, CA
Yes I have rechecked the codes & the only code is the P0153. No the light has never came on, other then 2-3 starts after a fuel up. Thats the only time it come on. So if it isn't related to fuel ups it is one hell of a coincidence. I guess it is possible though that the O2 sensor is on the edge of going bad & therefore only showing bad at times. I'm just trying to make sure it isn't nothing else that could be causing it, as I don't have the $50 to pay for a new sensor, just to find out it don't take care of the problem.
Tim, proud owner of 2001 Chevrolet Silverado 1500 & 2007 Honda CMX250C Rebel
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