I finally got one on my 95 Geo Prizm LSI. It's the first one I've ever had on a car and I'm already panicky. Strangely it coincided with my running the car almost out of gas and I was wondering if that could have anything to do with it. I had less then a half gallon left when I refueled. I wanted to see if I could push this tank of gas to 400 miles, but I never imagined that could make my check engine light go on; if indeed that is the culprit.
Congratulations. Did you check the engine? Is it still there? Excellent! You can relax now.
There are a number of reasons the check engine lamp will come on. Some of them are serious; most are not, or are some weird transient thing that will not recur. There's no way of knowing for sure unless you find someone with an OBD reader to tell you why. They can also clear the code to make the lamp go off.
Were it mine and running OK I'd drive it around for a week to see if it goes away by itself. If not, you can have the code checked to see whether it's something you really have to worry about.
(Actually, were it mine I'd check the code myself as I have an OBD reader - but that answer doesn't help you much unless you do, too).
-- Mike Harris Austin, TX
No need to panic just because you got a check engine light. I doubt if running the car almost out of gas has anything to do with the check engine light, but FYI, it is not a good idea to run the car low on gas because you can end up with drivability problems or a ruined fuel pump or clogged fuel filter.
The 1995 Geo Prizm does not have the OBD II diagnostic system so the good news is, you do not need an OBD II code scanner to pull codes, all you need is a paper clip. The bad news is, the trouble codes are not universal so you will need some kind of manual to interpret the codes.
To pull codes, un-bend the paper clip and connect terminals TE-1 and E-1 in the diagnostic port and switch the ignition key to the on position without starting the car. Count the flashes of the check engine light - you will notice a pattern of flashes and short and long pauses. For example, with "X" being a flash and "P" being a short pause and "PP" being a longer pause:
XXXX P XX PP XXXX P XXXX would be trouble codes 42 and trouble codes 45. If there is only one code, the pattern will repeat. A continuous steady flash means that no codes are stored in memory.
To clear the check engine light, pull the EFI fuse or disconnect the negative battery cable for 20 seconds or more.
The 1995 Geo Prizm is not OBD II compliant.
It can be as simple as the gas cap not being screwed back on tightly enough. BTDT.
Cathy
Actually, not on a non OBD II vehicle ;-)
3 broken paperclips later.... Ok, from the looks of it I'm getting the code 71 (or 17 and that's not in the book) which the books says is the EGR System. the next question I have is, what is the EGR system and how serious is it? From what the Haynes says, it's some sort of temperature system. After that, I have no clue where to go.
By the way, thanks for all the help guys. While I am rather clueless when it comes to cars, I am still wanting to try to learn about the inner workings of them.
Look in your Haynes or Chilton manual for instructions on how to get the engine code. HERE is how I got it with my 1994 Geo Metro which MIGHT be the same as your 1995 Prizm:
Once you get the code, turn off the key, replace the spare fuse, and fix the problem.
If it's the EGR valve, you can usually get by with cleaning them if you're cheap and don't depend to heavily on the car.
Once you've fixed the problem, you may notice the check engine light stays on. It's supposed to, for some reason. To reset it so it stays off, disconnect a battery cable for a few minutes. NOTE: disconnecting the battery cable will probably lose your radio presets and clock time, and supposedly loses information stored in the ECM or something about how you drive the car, but you can reset the radio and fuse box, and if the ECM learned once it can damned well re-learn how you drive.
and disconnect the battery cable for a few minutes to reset the
Not likely. The Metro is a Suzuki progeny, the Prizm a Toyota.
jim menning
The Haynes manual should point the EGR valve (which is usually what goes on them) out in there somewhere. It's part of the exhaust. It sends some exhaust gas into the engine intake when the car is cold. I forget why. It recirculates exhaust gas, which is why it's the EGR (exhaust gas recirculation) system.
You should probably replace the valve, but the one for my Metro was like $120 and that's roughly what I figure the car itself is worth at this point, so I took my EGR valve off, cleaned it with WD-40 and alcohol (it was gunked up with soot on the inside), cleaned the little filter thing attached to it and put it all back together with the original gasket and everything. That's a horribly slipshod way to do it, but it worked. The light hasn't come on since, and the car seems to run just fine.
If you're having trouble sticking a paper clip into a test port, you must have heeded your parent's warning never to stick anything into an outlet! ;-)
Old war story... A customer once saw me pull a code with a paper clip, and he was appalled that his expensive car didn't need some fancy special service tool to pull the code. After that encounter, I made up a jumper wire with male spade ends so that it looked a little more official.
The exhaust gas recirculation (EGR) system takes some exhaust gas and routes it into the intake to be mixed with the air/fuel mixture during above-idle operation. This reduces combustion chamber temperatures, which reduces production of oxides of nitrogen, or NOx.
This is a pretty good article that explains EGR operation:
An easy way to test EGR operation is to look at the vacuum hose attached to the EGR and follow the vacuum hose back to the vacuum switching valve. Very carefully pull the vacuum hose off of the vacuum switching valve (careful, the plastic connection may be brittle and break easily), stick your finger over the port on the vacuum switching valve, and with the engine idling, suck on nthe vacuum hose. The engine should start to run rough. If the engine runs normally when you are sucking on the EGR vacuum hose, then you probably need a new EGR valve.
If the engine does run rough, then take note of the suction on the vacuum switching valve port when the engine is idling. When you rev up the engine, it should suck harder on your finger tip.
After that, you will have to follow the EGR diagnosis section in a repair manual.
You're very welcome! My hat is off to anyone who is willing to get their hands a little dirty and learn!
The EGR valve recirculates exhaust when the engine is operating above idle to reduce engine combustion chamber temperatures, which reduces NOx.
It might take me a few days to figure out how to get this fixed; if it is indeed the problem. Is my car still safe to drive?
You may be able to remove the EGR valve and clean it up a bit, but it is probably a stopgap measure if the EGR is clogged.
Yes, if the EGR is the only problem.
Most egr issues I've seen are related more to the passages being clogged; What engine is in this and how many miles?
It's the 1.8L and it has about 140K miles.
From the looks of it, there are 3 vacuum hoses attached to my EGR, two going in one side of the top and a third one going in the other side. There is also another line coming out the bottom of it but it's a solid line and not a hose. Which is the line I am wanting to pull?
One thing interesting to note is that the valve says densco on it. I thought the Geo's were made with delco parts,
Steven Hansen, a Toyota Certified Master Diagnostic Technician, suggested that the EGR tube may be clogged. Before you take anything apart, mark the vacuum hoses and the ports they are attached to with different colored paint. I like paint pens that are available at hobby stores, but different color nail polish and white-out also work. this will take the guess-work out of putting things back together. Once you have a good idea of how to put stuff back together, you can remove the vacuum hoses and unbolt the EGR and look into the solid metal tube and inside the EGR. If it is all black inside, you can use a wire brush to clean it out.
Denso is part of the Toyota Group. The Geo Prizm is made by NUMMI, a joint venture between Toyota and GM, and the parts are supplied by various suppliers. My guess is that the engine and parts directly attached to the engine are supplied by Toyota and Toyota's suppliers, and parts like the radiator, suspension, and audio system are supplied by GM suppliers.
Check the gas cap
Why are you suggesting that the gas cap should be checked?
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