I just spent $75 on 2 new knock sensors (and that's cheap. local jobber price was $400), $85 on the wiring harness, labor to re& re and I STILL have the flippin CEL light for knock sensor. Car is still a bit sluggish slow.

according to flow chart, my ECU is the remaining issue. So where is ECU ? how hard to re & re?

Have others replaced all these and still had the CEL and issues for knock sensor?

 

What CEL code did you get? As far as the ECU goes, it's located behind your glove box. II'll try to explain as thoroughly as possible how to get to it.

if you get on your knees outside of the passenger side doorway and stick your torso in the car you should be able to look up at the underside of the dash. From the top of the car to the bottom you'll see three "sections": your glove box door, a carpeted trim piece, and a black molded plastic cover thing. Reach all the way back to the back (side closest to the engine) of the black plastic cover and pull down and towards yourself, You'll feel like your going to break it,, but this is kinda the norm it's only held in by some tabs that you have to pop around the surrounding trim pieces. (you'll understand when you get a good look at it.)

Then to remove the carpeted trim piece you'll have two phillips head screws to remove (they're in the corners) and pull it loose, you might feel some resistance, this is due to some spring clips on the backside.

Once you have that out of the way you'll be able to see the glove box door hinge which is secured by three hex nuts (10mm I think, might be 8?) they have dome tops on them, so you might need a deep well socket. once unbolted you can swing the door down and the guides on either side can come out of their holes the one on the left will just pull out, but the one on the right has a hook on it that a spring thingy (not sure what this is called) is attached to.you can reach under and wiggle it off of there and let it retract (it won't go anywhere; no need to secure it to something else) then swing the door's left side out to maneuver the hook out of its hole.

With the door out of the way you'll be able to reach a screwdriver up to the ceiling of the glove box and remove a phillips head screw. Pull the glove box out ( I find that it helps to pull from the top of the glove box where the latch is and around the top of the sides where there are little tabs) Don't forget to unplug the glove box light and trunk opener button on the left.

You'll be able to see your ECU, ABS computer, as well as just about every other wire in your whole car
The plastic wiring harness can really be a PITA the remove, I find a small flathead helps. If yours is like mine, you'll find a majority of your wiring harness stuffed between two of the modules, I can't remember if I had to remove another one to free it before I could get to the ECU, but I do remember there wasn't a way to unbolt the ECU without removing the electrical connectors from it.

Also, I think the bolts holding it in are 10 mm, I remember only needing one size socket plus a phillips to get the job done, but you'll probably need a 12" extension for your ratchet, it's pretty far back there.
Assembly is removal reversed. don't forget to reattach your glove box light/button wires and the spring thingy.

 

thanks. I may go pull one from a wrecker first.... best to make the mistakes there!!

ALSO, any idea if the Camry uses the same ECU in the 3VZ-FE motor?

 

Haven't actually put one in, but they are the same part and should work. (99% sure it will)

 

Here are the part numbers:

ES300
89661-33180 (07/1991 - 07/1992)
89661-33181 (08/1992 - 07/1993)
89661-33190 CALIFORNIA SPEC (07/1991 - 07/1992)
89661-33191 CALIFORNIA SPEC (08/1992 - 07/1993)

Camry (North American Produced)
89661-06020 (09/1991 - 08/1992)
89661-06021 (09/1992 - 08/1993)
89661-06040 CALIFORNIA SPEC (09/1991 - 08/1992)
89661-06041 CALIFORNIA SPEC (09/1992 - 08/1993)

Camry (Japan Produced)
89661-33120 (06/1991 - 07/1992)
89661-33121 (08/1992 - 07/1993)
89661-33140 CALIFORNIA SPEC (06/1991 - 07/1992)
89661-33141 CALIFORNIA SPEC (08/1992 - 07/1993)

As you can see there are differences. The Japan produced Camry's also have different part numbers versus North American produced. I don't know if these units are interchangeable or not, but I would venture to say if the pinouts match then probably. You can't mix Cali spec with Federal though that will not work properly.

 

i have a 93 that seems to fit this date: 89661-33181 (08/1992 - 07/1993)

On ebay, sellers seem to show 92-93, camry & lexus.

I plan to pull the one I have in my '93 daily driver that doesn't display CEL, and try it in the '93 "parts car".

I did a worksheet today and I've spent $2500 in parts & labor on the parts car, in the past month. I searched high & low for the best prices I could get on parts, and also had a very reasonable mechanic for many of the repairs. I also did a lot myself. I am trying to get $2500 for it and am not getting any sniffs right now. I am ready to hack my wrist over this poor decision. I just don't get people. I am frugal too , but I'm not stupid. To save $500 on something needing work (or soon to need work) instead of buying one where everything that wears out has been done already...with receipts & documentation... seems like a no-brainer to me. And my mileage is decent at 130K miles (=215K KM).

 

there is a rebuilder of these ECUs on ebay. I now wonder what's the deal with so many parts numbers. why wouldn't same vintage 93 camry have exact same part number? all I'm trying to do is clear CEL and get better low end performance like my daily driver.

 

You should check the wire integrity of the knock sensor to the ECU first before condemning the ECU itself.

 

the ECU part number is accurate. Mine is a 89661-33181. I looked at the connections going to it, and to the firewall (from inside car) and can't see any obvious loose connection or broken/chafed wire. how/where do i check from the knock sensor to the ECU? I replaced the harness under the intake manifold to the knock sensors.

BTW, great info stuckinva, especially the little spring thingy. it's like a presto pin clip that you slide forward to get it off.

 

CRAP!!!! I did the ECU swap between my 2 '93s. Exact same part #. CEL car is still showing CEL. Same poor mid range performance... at about 2000 RPM this car is flat and doesn't have response or pep that the other car has under the exact same conditions. Also, CEL car gets worse mileage.

so now what? I tried checking main wiring and harness but see nothing.

 

Are you sure you're even looking in the right place to begin with? What code did you retrieve from the ECU?

 

good point and beginning to wonder that myself. i am relying on what trusted mechanic told me. I did not read the code myself. I will do it tomorrow. I just replied to another thread; how to read codes. I noticed in that thread, a couple of other folks had the knock sensor issue and did everything I've done, and still had CEL.

Unfortunately, no final fix was posted = a pet peeve of mine.... you ask for help and get many people trying to help you...then you don't close the story by telling others the final fix??? seems rude to me. I try to post final fix, but I suppose we can all forget sometimes. I definitely reply if someone renews topic and asks.

 

Ditto! 100% agree.

 

I checked code and it is only code 52.

someone posted a link for me to Toyota Nation, where they discussed the knock sensors for my 3VZ-FE, and how to check resistance. they also talked about using an oscilliscope. this is what I posted there today:


I tried the test again today. when i set my cheapo meter to 2000k or 200K resistance, it displays "1" or "1." . If i check a piece of meteal or touch the 2 leads together it shows "0.00" for continuity/resistance.

So, when I ground one meter lead to NEG terminal and check both of the brass pins seperately (even checked the silver pins), I show "1". Like it's not registering any resistance at all. These are new sensors and new wiring harness. Shouldn't I get something? Not sure as this is a very basic, cheap meter.



I also checked code again and it is only code 52. I do NOT get code 55. I do not get any other codes.

will the oscilliscope show the output & give a better diagnosis?

 

You mentioned you got the sensors for cheap so i am assuming they are either non oem or from a junk yard. What you have to realize is alot of sensors from online and non oem turn out to be crap. A

For such critical sensors and the labor it takes to get to them, i would defiantly try and stick to oem sensors here.

I believe that these new sensors are probably bad and not the ecu.