I live in California and have a 2000 Jeep Cherokee Sport. Occasionally (perhaps once a year) the engine light will come on. I'll get antsy and plan to take it in for service. But the light only stays on for a couple of hours then goes off. I mention this to the service guys and because the light isn't on, they have no clue.
What sort of problem causes the engine light to come on?
Shouldn't the Check Engine Light set a code in the computer? Shouldn't the service guys know how to read the code and see what set it? I think you're correct when you say, "..they have no clue."
Go to an Autozone and get them to read the codes that the system puts into the computer when the light goes on (they do that for free, no problem). Then report them here and the folks here can tell you what they mean and what to do. Tomes
Since this happens for just a few hours once a year, a loose gas cap would fit the symptoms. But since all who replied have said to "read the codes" -- and I'll do that -- I assume that whatever caused it to come on is stored in the computer -- kind of like a diary -- even though the light itself has long since gone off.
Fault In Companion Module No CCD/J1850 messages received from the powertrain control module-Asian transmission.
P0141 (M) O2 Sensor Heater Circuit (Bank 1 Sensor 2) Oxygen sensor heater element malfunction. O2 sensor voltage greater than 3 volts for 60 to 240 seconds.
P0455 (M) Evaporative Emission Control System Leak Detected (large leak) A large leak has been detected in the evaporative system. See TSB
25-001-02. Also, possible faulty or loose gas cap. Note: The respective Powertrain Diagnostic Procedures Manual will direct the technician to determine if the vehicle evaporative system has an external system leak. Examples of some external system leaks are: a loose gas cap, a disconnected evaporative system hose, or a loose hose connection. Remember that the evaporative system may also have an internal system leak. This internal leak may be caused by an intermittent or permanently stuck open Duty Cycle Purge (DCP) valve. This leak source is considered to be internal because any escaping emissions enter into the engine system and not directly into the atmosphere, unlike an external leak. An internal leak may cause one of the above DTC?s. Possible causes of a stuck open (intermittent or permanent) DCP valve are: 1. Corrosion due to system moisture or possible water intrusion into the system. God Bless America, Bill O|||||||O mailto: snipped-for-privacy@aol.com
Jeff, I think you're overlooking the main cause of the problem. Read Alan's next to last sentence above, he doesn't need a scan tool, he needs a different service place! He's taking his Jeep to people who apparently don't know to scan for codes and as long as they're servicing his Jeep he'll be having problems, I'm afraid.
I took the Jeep to a different service place that I had used before that was on the list of AAA-proved repair shops. They checked the codes and determined that one of the three catalytic converters had failed. They said they also checked to see if it was just a bad sensor. They said that parts and labor for a rebuilt unit would be about $1500. New would be about $1900. They also said I could drive it for a few months (maybe longer) without damaging anything, but that if a smog test was upcoming, it wouldn't pass. I drove the Jeep for a about a week and then yesterday all by itself the engine light went off.
I didn't keep an accurate record, but here is approximately what has happened. A year and a half ago, the engine light came on for a few hours then went off. Six weeks ago it came on for a few hours then went off. Two weeks ago it came on and stayed on for about 10 days. It is now off.
Is that what happens when a catalytic converter is failing but hasn't yet failed completely? Or does this behavior portend something else?
I have 109,500 miles. Yes, I will check other places before I spend that kind of money. But I wanted to get some idea of whether this on-off-on-off thing with the light is a reasonable occurance if the cat has failed or is failing.
Are they including a new engine with this Cat? If not, they are thieves. Certainly 'not' trustworthy enough to give you a straight code answer.
A loose gas cap even will cause the check engine light to come on intermittently.
Can you not get your own codes on that one? I don't know, but if you can, you turn the key to get them. You go to run, off, run, off and run again and watch the dash for either a blinking light you count the flashes or a series of numbers starting with a P will flash.
Some auto parts stores will also check the codes for free.
If you can get that, then let us know the codes.
You can also clear the codes by unhooking the battery for a few minutes so if the light doesn't immediately come back on, you shouldn't get suckered for emissions.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's - Gone to the rust pile... Canadian Off Road Trips Photos: Non members can still view! Jan/06
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I was getting a random check engine light a couple months ago. Disconnect my battery to re-set the codes and it would come back on once in a while. Was starting to do the research to correct this then I happened to check my oil and the dipstick was not down tight in the tube. The light has not come back. Coincidence?
On my YJ I swapped in a new cat for around 200 bucks
"One of the three" catalytic converters? There is only one. They want to sell you a "rebuilt" unit? Run, do not walk, from this place. I would guess you have an O2 sensor about to go, probably time to change all of them. Often an intermittent CEL will indicate a minor emissions fault, which isn't critical to engine operation. A failed cat means you will hear the element rattle inside the housing.
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