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1993 Toyota 22re- CEL comes on but dealer couldn't get the engine light to flash. Not sure if this would affect it, but I have a base 4x4 and swapped out the cluster using a SR5 cluster with a tach. This cluster has been in for years w/ no issues. Could that be the reason for not showing a code???
when the light comes on, I can feel the power is down and at times when the light goes off the truck pick up power. Mostly the light is on but occasionally it goes off. When the light is on fuel milage drops to 13mpg hwy...I had to drive the truck about 250 miles in this condition....Truck is a one owner w/ 142,000 miles. Original cat, MAS, plugs look good, O2 replaced in 2017 ( low miles). Not sure where to turn. If I put the original cluster back in will I be able to see the codes??? Or is it just wired to a light and shouldn't make a difference. I'm not sure what to do or look at.
I assume that the CEL comes on with key-on, but once started the CEL "usually" switches off. Occasionally, the CEL comes on, and at that time, power is reduced.
I doubt it's the combination meter (cluster), because this is normal behavior. It sounds like you're not successfully connecting E1 to TE1. Start with E1, which should be ground. Use a test light from E1 to battery+; it should light. Next, measure voltage from TE1 to E1; you should get about 12v. Then, use your ammeter to connect E1 to TE1. I get about 0.5ma. Last, measure voltage from W to ground. W is the same as CEL; you should get 12v to ground only when the CEL is on. (All these tests require key-on.)
If the tests fail for E1 or TE1, I would suspect a wiring issue from each to the ECM.
Could it be you've never tried to read the codes on a 2nd-gen 4runner or pickup?
With a tiny number of exceptions, an "OBD code reader" reads OBD-II codes. OBD-II was required for the 1996 model-year on. Which does not include our trucks. Which is why I included the link to the FSM, just in case you didn't know how to read the OBD"-1" codes.
Your $600 scan tool won't help; there's no place to plug it in! But a $0.01 paper-clip will do the trick.
[Technically, there do exist some expensive scan tools that have an "OBD-1" function. They just include instructions on how to jumper E1 to TE1, and read the flashing CEL. Which instructions you just got for free, courtesy of Toyota.]
Thanks for the TE1 and E1 test info I will check that-
Changed the cluster back for the original and no change on the CEL....
The CEL stays on when running, for the most part. Occasionally it goes off and the motor picks up and runs smoother for a bit...or with the CEL on sometimes the engine bucks a little but quickly stops. Note before the CEL light came on I got 20 mpg....next tank with CEL on down to 13mpg hwy.
I've connected to TE1 and E1 and when I turn on the ign, the CEL light stays on..no flashing codes....sometimes when I turn the ign off then on it flashes continuously.....once it flashed like it was going to repeat then just stayed on.
I pulled the ecm and saw a resistor (?) which has some of the clear off it, probably got to hot. BTW truck has 140,000 miles and well taken care of. O2 sensor was replaced in 2017 and MPG figures are 20 mpg hwy so I don't suspect cat or O2 sensor.
Last edited by 93 Toyota 4x4; 05-11-2021 at 12:24 PM.
"Gee, Doc. My finger hurts. Could it be broken?" "Don't know, but I think we'll start with brain surgery."
Leave the ECM alone. Yeah, you could have a problem there, but it won't be as simple as an open resistor (that's a 2 watt resistor, judging from size; they're supposed to be pretty toasty).
Wires, on the other hand, are hanging out in the cold and rain. They could go bad. Run the tests I suggested. If necessary, "Tone-out" (check for continuity) the wires from the diagnostic connector to the ECM.
You should always start with the easy stuff and move on to the hard stuff. Messing with the internals of an ECM is definitely the hard stuff.
FWIW, I fear in the end you'll find a code 52: knock sensor circuit. Lots of threads on that. If that code is thrown, the ECM dramatically retards the timing to save the engine. Retarded timing => runs like poop.
I did notice before the CEL came on there was no preigniton, which I usually get a little when under a slight load...and also none with CEL on......thanks for your insight!!
BTW I wasn't going to mess with the ECU any further.....that's way beyond me
Last edited by 93 Toyota 4x4; 05-11-2021 at 07:23 PM.
Well, you're not the first person to think that the knock sensor is sorta like an oil pressure switch; the sensor throws the code when the engine is knocking. (pre-detonation). Not. At. All.
100 years ago, your Model T had two levers on the column: throttle and ignition advance. 50 years ago, your Camaro handled advance for you, with centrifugal weights and vacuum advance. Very approximate and rough. 35 years ago, your pickup was getting smarter. The computer would carefully advance the ignition until it just started knocking, back off a hair, then repeat. It relied on the knock sensor to tell it when to quit advancing. But what if the knock sensor quit? If the computer stopped hearing from the knock sensor, it knew there was a problem (and threw your code 52). But where was it at now? Without the knock sensor providing guidance, the timing could be so far advanced you're about to blow a hole in a piston. So to save the engine, the computer dramatically retards the timing.
So when the engine is okay, you never hear the knocking, as it only happens a tiny bit. When the knock sensor quits, you definitely will never hear knocking.
by any chance do you know the wire colors for the TE1 and E1??? I want to make sure I'm checking the right ones...plus the socket size of the knock sensor??
A little up date in case anyone is curious...I sent (5-13-21) the module off to Module Experts to diagnose. Either fix ($193) or replace (+$900). I did do a search for used ones and found out the one my truck uses is the rarer more expensive one..used ones from 800-1250......reman for $900. The module arrived on the 22nd..so the moment of truth...While waiting for it to arrive it gives the mind time to worry about "what it could be.' The way the truck acted and knowing it's history..I'm the original owner...I highly doubted it was the O2 sensor (replaced 9,000 miles ago), not the cat...fuel mileage was typical the last few tanks....idled well and no missing, spark plugs looked great.. I was really thinking if it was external it would be the knock sensor..ordered one and the old one checked out the same as the new. What made me think it was most likely the ECM was that it wouldn't flash a code when the two terminals were shorted out...and when it did flash it was nonstop. So sending it out so quickly was a leap of faith on my part.
So what happened when the ECM was plugged in????? CEL on with ignition switch and off once started......it now works as it should...just a few $2 capacitors...then their labor of course so guess it's better to be lucky than good.
Module Experts didn't supply a reciept with an itemized repair...I will call them Monday to get and itemized receipt w/ lifetime warrantee.
Last edited by 93 Toyota 4x4; 05-22-2021 at 03:00 PM.
I highly doubted it was the O2 sensor (replaced 5 years ago and very few miles), not the cat
Just a note. The O2 sensor needs to be replaced every so often. I thought I read someplace that the interval is 60,000 miles, but I might be way wrong on that. I know my 87 4Runner started throwing the code for the O2 sensor at 100,000 mi. , so I replaced it, and it's a happy truck again. That was 20+ years ago, but not that many miles. We only drive it in the winter up here, so...
Another trick I got from the professional mechanics I worked with was to beat up the cat every once in a while. It sounds like cruelty to animals, I know.
Take a rubber mallet or ballpeen hammer, and whack the heck out of it. Obviously, not enough to do any damage to the cat, pipes in and out, or the screen under it that keeps things from touching the hot case. Just enough to "shake it up". I do it every spring, and it makes a big difference. It runs better, and the exhaust smells different. I understand the bedding gets settled in, and develops a layer on top of it that changes the way the cat affects the exhaust gasses. Beating it now and then shakes it up, and gets the fresher, "unused" bedding into play. I've been doing it every spring for the last 25+ years now, and as I said, it makes a difference. Both trucks.
Having said all that, these were the same mechanics that said another way to improve the cat's function was to pull it off, take a big screwdriver and stick it into the cat and scrape it around real good. Dump out the bedding materiel, and put it back on. Voila. No more cat or problems with it. This was in Yuma, and we had no inspections there, so doing that wouldn't matter.
They also helped me pull 90% of the silly air injection, and other "make the exhaust cleaner" stuff, off my pickup.
05-10-2021, 08:24 PM
