Should CEL come on with oil change warning?

LS-jsf

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The check engine light came on the same time the time to change your oil warning popped up, is this normal? The change oil setting was reset but the CEL came on when starting the car again. If this is the cause, is there a way to self turn off the CEL? Thanks for your help. 2003 V8
 
No, they are two separate things.

It would be best to get the code read so you know what is malfunctioning.
 
Just seems odd that very recently had the CEL come on, had the codes pulled up at AutoZone P0174 & P0171 - MAF (Mass Air Flow Sensor) - car always ran fine, then the CEL just went away on its own. Now 500 miles later the exact moment the change oil warning comes on, the CEL comes on also. Can there be an issue with the CEL itself?
 
... Can there be an issue with the CEL itself?

No, it's trying to tell you that there is a problem. Don't shoot the messenger.
What troubling shooting have you done to determine that this is a MAF problem?
 
I wasn't shooting the messenger, just thought since almost anything else can not work correctly at some point, why not the CEL also. I haven't done any trouble shooting other than getting the codes read before and then the CEL went off right after that and continued to run normal. The car is in LA right now and I'm in LV. In LA you can't take a car to say AutoZone to get codes read, they don't allow it. Our mechanic is here in LV so I'll be waiting for her to bring the car back here to be checked out as long as the car continues to run fine. Is it normal for a CEL to turn off on it's own?

No, it's trying to tell you that there is a problem. Don't shoot the messenger.
What troubling shooting have you done to determine that this is a MAF problem?
 
Yes, if the PCM no longer detects a problem, it clears the DTC after a few cycles. This is why I sometimes get annoyed about people clearing codes. If they really fixed the problem, the light will go off after a while anyway. If they didn't the light will come back on.

Don't put much stock into Autozone's guess that it is MAF related. It could be caused by at least a dozen different things.
 
She just filled up with gas (15 Gal) and when she started it the CEL was no longer on. Does this mean anything, should I get a new gas cap in case it's not sealing properly?

So the codes from a couple weeks ago (AutoZone) P0174 & P0171 don't either mean MAF or maybe a possible vacuum leak? You mention it could be caused by at least a dozen other things. Would a shop with better scanners be able to diagnose it correctly?


Yes, if the PCM no longer detects a problem, it clears the DTC after a few cycles. This is why I sometimes get annoyed about people clearing codes. If they really fixed the problem, the light will go off after a while anyway. If they didn't the light will come back on.

Don't put much stock into Autozone's guess that it is MAF related. It could be caused by at least a dozen different things.
 
...Would a shop with better scanners be able to diagnose it correctly?

You can't just plug something in and get a correct diagnosis that isn't much more than a best guess. Correct trouble shooting requires inspection and instrumentation, and following the correct processes.

A lean condition without misfire would possibly be
air/vacuum leak
low fuel pressure
clogged/dirty injectors
Bad TPS
bad/dirty MAF
bad O2 sensors
bad gas
...
 

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