What's the most serious condition that will cause a constant CEL (non-flashing)?

[TinyIvan]

What's the most serious condition that will cause a constant CEL (non-flashing)?

Everyone knows that if it's flashing your next stop better be the dealer, but if it's steady it can be anything from a gas cap to a bad EGT sensor. The gas cap won't do squat and will go away but the sensor will cause reduced performance and should be fixed. It also probably won't go away on its own

Soooo, the question is: I had my third CEL go on, but need the car starting Wed for a weekend trip. Since it's a steady light, am I OK to drive a couple hundred miles and hit the dealer on Monday? It really torques me that I have to deal with these but I think I will have to spend my money, give up my hope of a CEL-Free existence and buy an OBD-II scanning tool.

BTW, my car is bone-stock.

Thanks!

Notes: Two prior CELs: P0546, twice, turned out to be an intermittent short in the wiring harness somewhere in the firewall. Replaced EGT and fixed harness.

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[Julian]

The answer: Who knows? Say its another short, but this one happens to contact a ground, then bzzzzzzt!, you let out the magic smoke, and...

Sure constant-CE light codes aren't as serious, and you could probably drive and be fine, but until the code is pulled there's no way to tell what it is.

With scan tools going for $73 in the various GBs, and a laptop for $100-150 or so, it's totally worth it. With my CE-throwing MRT header, it's nice to be able to check that the only code I'm throwing is P0420.

[gusman21]

do you know where your short was?

i have a similar problem and i have replaced the EGT sensor once already and i have the 0546 AGAIN.

-=GuS=-

[Jon [in CT]]

Speaking of Exhaust Gas Temperature sensor failures, they frequently first manifest themselves as a benign solid CEL. However, they can quickly morph (in a matter of hours or days) into a failure in which the ECU believes there is a fire in the exhaust destroying the catalytic converters. In this situation the ECU has been known to panic and actually shut the engine down completely.

[TinyIvan]

Check out this post for the reasons behind my code:

http://forums.nasioc.com/forums/show...ighlight=short

Text:

TinyIvan PM'd me that his P0546 problem has been fixed. I thought that the resolution ought to be appended to his original thread so that whenever someone searches the forums for that trouble code, they'll find how it was cured for one person. I hope TinyIvan doesn't mind.


quote:
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TinyIvan wrote on 04-11-2002 11:54 AM:
Thanks for your suggestion on not letting the CEL on P0546 just keep bothering me. I wrote a letter to SOA, then called when I never got response (still bothers me actually, no written response). Eventually I got in touch with someone with their head on straight and receieved a case number.

Turns out they must have known about the lemon law as well because they brought in a factory rep and he found the problem in ONE day. There was a disconnected ground on a bus board under the passenger footwell.

The thing that ticks me off is how they found it (my conjecture based on conversation):

1) Drive around with computer hooked up.
2) No EGT reading (steady).
3) Look for reason its steady.
4) Must be ground since it's a high output.
5) Trace ALL ground paths (not just harness).
6) Find disconnect.

How this took three attempts (maybe two b/c I am convinced the first time was just a reset and go) I will never know. Maybe I should buy the service manuals.... BUT I don't think I should be fixing a stock car under warranty. Anyway thanks and keep up the good advice!

-TI