Can cold weather cause a CEL
 

I'm on vacation in Lake Tahoe. It's been pretty cold and the snow is falling in a steady fashion.

My 2004 Taco got a CEL today while driving in the cold. My truck runs like a champ. It has 50k miles on it and only has a large case Dynomax muffler on stock pipes.

I don't have a code reader on me. I already tried disconnecting the battery, that cleared the CEL momentarily. But the next time I drove it, the CEL came back.

Can it be the cold?

Am I ok to drive it with the CEL? I'm 500 miles from home.

find a way to read the code. Autozone or other auto chain stores might be able to read it for you. Depends on what it is whether or not it's safe to drive.

cold weather MIL ?

99% likely the maf just needs to be cleaned, ecu reset.

cold weather, spring rains...this is enough to make a dirty maf throw a code

Please explain in terms a newb can understand what is a CEL ?

Guess: constant engine light.

Check engine light

Autozone will pull it
some tires stores will as well
I bought a cheap reader for $80
I keep getting P0450 from the gas cap, if it gets cold it will pop a code about once a month

Ok. I leave tomorrow for the drive home. I'll try and find a place to read the code on my way home. I hope its nothing.

Thanks for the replies

you can drive it all day long with a cel on. its when it starts to flash, usually a misfire is when you dont wanna drive it

it's -20 here, and ive still never gotten a CEL

Not in cali


:dj:

Here in PA they will read it but they won't reset it. Just so you know anytime the CEL is on the ECU is gonna run the engine slightly rich. This isn't good for an extended amount of time. 500 miles though it should be fine. But if it's a Knock Sensor code or a Cat efficiency code I wouldn't want to drive the vehicle for 500 miles straight. There might be some other codes, but I never memorized them. Those are two off the top of my head I can thing of that I wouldn't drive it.

I made the mistake when I was younger to drive with a CEL on for 6 months on a car with 15,000 miles on it. I wound up with a clogged cat that rendered the engine inoperable.

lol wut ?

this makes no sense. anytime the MIL is on you need to know
exactly why, only then can you determine if it will change the mixture
and run rich, if at all.

I can name 4 bank 1 sensor 1 codes where the MIL will light
and it will run extremely lean and start to destroy the valves
if ignored for a long time.

first time my MIL lit up -ever- was 2003, cold and wet. cleaned the maf good to go

30,000 miles later, again MIL lit up when cold and wet. checked MAF, had crud on it.
cleaned it, MIL gone, good to go.

* Malfunction Indicator Lamp = MIL there is no such
thing as a 'CEL' in any Toyota published diagnostic routine

with the ECU and a CEL on the ECU changes the fuel map (keeping the engine in open loop) to make the engine run a little rich to protect itself. If it doesn't a bad sensor can and will cause an engine to run lean depending on which sensor and how it failed.

I know a CEL on an OBD 2 vehicle does this, not sure about a pre-96 though.

I got a CEL when in really cold weather on a long road trip. I think the O2 sensor might be going or had a loose connection due to ice buildup.
I reset it when I got back and haven't had it back on since. However get it read to figure out what it is

It depends on the DTC that triggers the MIL/CEL. Not all DTC's put you in open loop. For example, I have had P0420 and still been running in closed loop. A decent scanner will tell you if you are in open or closed loop, my BR-3 does.