Check engine light comes on, then off ..

Question

while driving at 70 mph for over 30 mins check engine light came on but went off when i got into town, it also came on a week later when i had the cruise control on for apox one mintue and then went off

question is, can i take it to autozone for them to plug in there machine to test my car, even though the check engine light is NOT on ?

just recently did tuneup- plugs/wires-fuel filter-oil change-raditor flush but thinking dont think have changed oxygen sensor in a while

94 nissian atlima-160k

Answer 1

this vehicle may not store the codes. most likely the egr tube to intake port stopped up due to the light on at highway speed. (EGR LOW FLOW)

Answer 2

that is what is called a soft fault. the cpu will store the code for quite  while. you will be able to pull that to determine the problem.  

Answer 3

did you change the air filter element?  If not, it could be the culprit.  (Seen it time and time again).. also,

Also, you may have a failing converter.

To check for codes, the ECU is under dash behind the center console.

You must remove the computer (Do not disconnect battery and Keep computer connected to harness or you will erase the codes)  turn the ignition on, start the engine and warm to operating temp.  Turn the diagnostic mode selector switch (on the computer with either a screwdriver or push switch) - wait until the inspection lamps flash (located on side or top of computer) and count the flashes for each code in each mode.- The red LED is units of 10, the green is units of 1 while retriveing codes. - the inspection lamps  - 1 flash = Mode I,

2 flashes = Mode II

after 3 flashes (Mode III self-diagnostic mode) turn the doagnosis mode selector to OFF or Fully Counterclockwise.

Answer 4

take it to a local auto parts store and they will read the computer for free

Answer 5

check for a lose gas cap. I have a 94 nissan sentra and sounds like what my vehicle did. Check the vaccum hose on the EGR valve. Could be split or just rotted. That will cause engine check light to come on and off again

Answer 6

Sounds like a leaky gas cap or Oxygen sensor. Unfortunately, you are going to have to catch it with the light on.  I went through a similar issue. I'd get it up to the auto place and it would be out. It finally stopped doing it fortunately but if the check engine light is out then the computer won't pick up a problem as the computer thinks everything is fine.

Answer 7

Your dealer has a machine that will analyze the problem. Get them to diagnose it and then get someone else to fix it unless you are under warranty.

Answer 8

have it checked should be stored

Answer 9

Even if the light isn't still on, the computer of most cars will set a code in memory to help you track the problem. It won't give you a definite solution, but it will tell you the general area to check out. Intermittent problems are the hardest to diagnose. The oxygen sensor isn't part of regular maintenance, but they do often fail.

If you can't figure it out on your own, you might take it to a shop that can hook up for diagnostics while driving.