"Check Engine" staying on most of the time now [Archive]

View Full Version : "Check Engine" staying on most of the time now

Suzu

07-01-2015, 02:15 PM

Hi all,

My van's Check Engine light has been staying on a lot lately. It used to only come on occasionally while driving at highway speeds and would shut off if I shifted into neutral and coasted for a little bit. (It's a one-owner van and did this ever since it was brand new.) Now lately it is coming on when I start the van and while driving in town. It only goes off when accelerating up a hill.

I haven't driven at highway speeds for a while because I need to change the thermostat and haven't had time to do that. How do I figure out what's wrong? It's an '87 5-speed, and it's been raining all the time here lately, too (in case these items matter).

Thanks!

llamavan

07-01-2015, 04:31 PM

Suzu

05-19-2016, 10:23 AM

You'll need to check for stored codes to get started on this problem (which could be very complicated now that it's been ongoing for some time).

Go HERE (http://www.toyotavantech.com/forum/content.php?196-Engine-Service-Connector) to learn how to check for codes.

Then, go HERE (http://www.toyotavantech.com/forum/content.php?195-Diagnostic-Codes-for-Toyota-Vanwagons-all-years) to learn what the codes mean.

Gwen

I tried this a while ago and didn't bother posting about the experience, but I will do that now.

I know it says to do it when the engine is warm but since I was completely unfamiliar with the procedure I decided to check it out beforehand, just to be sure that I knew which plug to use, etc. I removed the rubber caps on the plugs until I found the one that looks like the one in the photo. Then I stuck the paper clip into it, and, bingo, the codes started flashing. I didn't write them down. I didn't have the list printed out and handy either.

Then I drove around until the car was warmed up, and tried it again. This time I had the printout of the codes in hand. But nothing happened when I tried to do the procedure. I got a mechanically inclined friend involved, too. I made him read the information in the thread you referenced, and then we tried again. Nothing happened.

We tried it several more times. Sometimes with the key on on sometimes with the key off. No results. No flashes whatsoever.

Then a while later I noticed on the door of the local O'Reilly auto parts store a sign that says if your check engine light stays on, they can check it for you, at no charge. So I went over there with the van, and the man asked me whether the port is square or round. I said it was round. Then I showed him the plug I had been trying to use, it was nothing like what his machine is designed to connect with.

I should mention that I had heard something about OBD ports before. I was told by my insurance company that I could get a discount on auto insurance if my car had an OBD2 port and would let it be used to monitor my driving habits. They said, too bad, your vehicle is too old and has an OBD1 not an OBD2, so it won't work.

The sign at O'Reilly had mentioned the OBD port. So I asked them if they could check OBD1 ports on older vehicles, and they said yes. But no one seems to know where this port is on the Toyota van.

I want to fix the car. What am I supposed to do next please?

Suzu

05-19-2016, 11:05 AM

I called a Toyota service dept and they say this van does not have an OBD port other than that plug mentioned above. So at least that mystery is solved. I still don't know how to get those codes to display though; Dealer wants $110 to check this.

johnnyvegas

05-19-2016, 09:42 PM

timsrv

05-19-2016, 10:01 PM

Right there in the quote you just posted, that 1st link within, here's what it says:

The "Check Engine Connector" is among a group of 3 dead-end terminals right behind the air flow meter. It's the medium sized one and the only one with 2 wires going to it. One wire is brown and the other is gray with a black stripe. Here are some pictures of the "check engine connector":

http://i8.photobucket.com/albums/a23/timsrv/IMG_0104.jpg

Does that not answer your question?

Looks like your van harness has previously suffered a "hack" job. I hate it when idiots do stuff like that. You can still identify the wires by the colors (quoted above). Just twist them together and that should put the van into diagnostic mode. Tim

Suzu

05-19-2016, 10:39 PM

Looks like your van harness has previously suffered a "hack" job. I hate it when idiots do stuff like that. You can still identify the wires by the colors (quoted above). Just twist them together and that should put the van into diagnostic mode. Tim

Not mine; looks like my topic has been hijacked.

Burntboot

06-13-2016, 10:37 AM

Suzu - We're not ignoring you, it's just that your question was answered by Lama's post.
I am sorry that you're having trouble pulling codes but without being there, its hard to know what your issue is.

That said, I have found the paper clip method isn't as reliable as a proper jumper wire. It is possible that a paper clip isn't making a good connection with the connector.
Grab a small piece of wire (2-3in is all you need) and crimp a male spade connector on each end. (when your done, keep it in the glove box for future use)

Once you have a proper connector made, install it in the proper plug then turn the key to the "run" position (engine NOT running) and you should see the check engine light flash. if it flashes on and off in regular cadence, there are no stored codes. If there are stored codes it will flash just like it did the first time you tried this.
Don't worry about having the list handy, just use a pen and paper to record the flashes, it will flash out all the codes (morse style) and when it gets to the end, it will repeat the sequence again (and again and again....) Now you can cross reference what you found with the list of codes.
Also understand that codes are merely an indication of the "system" at fault, not necessarily a faulty part.
(What I mean to say is that the computer doesn't know the difference between a faulty O2 sensor or a broken wire to the O2 sensor, all it knows is that sensor isn't responding in the manner it is expecting to "see")

It is also wise to remember that anytime you disconnect the battery you will erase ALL stored codes, in that case you'll need to drive it for awhile to reset them.
The CEL won't always illuminate when it see's a fault, it seems to depend on how critical the fault is, but it will store fault codes, which is why its important that anytime you have weird symptoms, you start with checking codes, whether you've seen the light or not, this eliminates a lot of the guessing and doesn't take much time to do.

While some boards prefer to have a separate thread for each "complaint", Tim likes to have similar problems posted within the same thread, all together, that way when someone is searching for an answer, its often easier to only need to search one or two threads, not hundreds.
Personally I like it this way, makes finding an answer easier and it keeps things nice and tidy.

As to your other questions on what parts to buy, while OEM parts can be expensive they ARE foolproof.
For the record, I have never gotten an OEM part that was defective right out of the box, with the exception of "new" parts that look like someone has used them previously, and that was only once.

Aftermarket parts are generally designed to fit as many applications as possible as it reduces the need for more inventory, however, sometimes those similarities aren't sufficiently close to the proper spec.
Nothing worse than installing a new part, only to have the same problem and later find out it was the new part that wasn't really compatible.

As for thermostats, I am sure there are lots of AM parts that are just fine, but for those of us who have run into issues, it simply a case of once bitten, twice shy.
Personally I have seen so many AM stats screw up that I will no longer take a chance on them, regardless of what I am working on.

Our vans have little tolerance for things "not quite right" and when it comes to the cooling system, we have learned the hard way, not to take chances.
You know the saying, "do it right and do it once", if the problem isn't solved, you can now confidently move onto the next likely suspect instead of second guessing whether that AM part is an issue or if the problem lies elsewhere.

So make your jumper wire and recheck your codes and then come back to THIS thread and let us know what you find.
I am sure you will get the answers you need.

Cheers
BB

Suzu

06-13-2016, 11:07 AM

Suzu - your question was answered by Lama's post.
I guess you're seeing something that I missed subsequent to 5/19/16.

the paper clip method isn't as reliable as a proper jumper wire...
Grab a small piece of wire (2-3in is all you need) and crimp a male spade connector on each end.

Thank you. I will try this! (after I figure out what a spade connector is LOL)

It is also wise to remember that anytime you disconnect the battery you will erase ALL stored codes

I had no idea.

As to your other questions on what parts to buy

I don't remember asking that -- at least, not in this thread.

So make your jumper wire and recheck your codes and then come back to THIS thread and let us know what you find

I sure will. It might take some time but I will -- because I do not own a money tree!

Thanks for all the info <3

Suzu

09-10-2019, 05:54 PM

Well I see that I never updated this thread. What I ended up doing was replacing the ECU. Got a decent used one on ebay for $120. Now I don't have CEL problems anymore!