My check engine light has been on since I bought my 1990 toyota pickup over a year ago. I take it to the dealer and they say its a code 52(knock sensor) and want $1500+ to fix it. So I'm like screw that! idt so lol. I then take it to a mech down the street and i tell em what i think is wrong. They fix the knock sensor, buut.. the check engine light is still on, over 900 bucks later and nothing is fixed but they did tell if I asked them to do a diagnostic they would have found out that its the ecm/ecu. Im like well thanks for trying to help me out a-hole. anyways my question is what do i need to do? can i get it my self and do it.. should i just take it in and get it done?

I seen on parts geek they have a Engine Control Module PROM - Computer Upgrade Kit for about 280 bucks.

Oh and get this! they dicks at the dealership say it'll be about 1200 for a new computer! are you serious! no way I'm ever going there. ever.

so maybe there might the some mech in here that can help me out too?

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That sounds to be about the right list price For a ECU

Just what year truck are you working on??

If you list all the needed info some one might have one for sale.

Are you sure now that it is a faulty ECU ??

Perhaps a used ECU on here ??

Rebuilt one from ECM Depot I bought one from them I am happy

 

Its a 1990 toyota pickup.
not sure if its a base or an sr5 though
the mechs said thats what it was. i mean i wouldn't know if they were lying to me or not haha

 

Go to www.car-part.com and look for an ecm. Should be able to get one for around $100.

 

Before you start replacing parts ....

Pull the codes. http://personal.utulsa.edu/~nathan-b...85diagnosi.pdf If you haven't gone through that exercise yet, you're a long ways from replacing an ECU no matter what you pay for it.

PS. You'll need the Special Service Tool: http://www.staples.com/OIC-3-Size-Pa...product_525915

 

I agree on pulling the codes and figuring it out. But also wanted to give the info on where to get the ecm, instead of paying $$$.

 

the mechs at the dealership said i need a specific ecm and needed my vin #
to find out which one. so thats why im hesitant to buy online.

hahaha a paperclip.

any idea why it would be trowing a code 52? when the knock sensor has been replaced?

 

I found this on pirate4x4 and the guy found it on here lol
but the last post shows ecu #'s but its for 22re's

Im searching numbers now so hopefully i can find something
then get with the mechanics in the next couple weeks

 

http://www.pirate4x4.com/forum/toyot...ibility-3.html

 

First, WHY do you think you need a new ECU?

"...they did tell if I asked them to do a diagnostic they would have found out that its the ecm/ecu."

And just what "diagnostic" was that? It doesn't sound like you have much confidence in their work.

If you are convinced you need an ECU, you should ALWAYS use your VIN when looking for part numbers (especially an ECU). Lots of online dealers will do it for you. http://www.toyomotorparts.com/ is one.

You have code 52 because you have a wiring problem (most likely the "pigtail." ) The sensor itself is quite rugged, and I don't think it fails very often. But the pigtail is just special wire (shielded) and is in a hellish environment. Why someone would replace a knock sensor without replacing the pigtail is a mystery to me, but it doesn't sound like you've been getting the kind of service you want.

If you search a bit here, you'll learn that when you get code 52, the ecu dramatically retards the timing (to save the engine), which means your truck really runs like crap. So you need to fix that code before you waste any time on a replacement ECU. (Unless you are absolutely positive the ECU is bad - it's about $650)

 

since they replaced the pigtail and knock sensor it was still coming up. idk what exactly they did but by their diagnosis its an ecu.

If i do find an ecu thats compatible can i hook it up myself?

 

Very easy to replace by yourself

 

well thats good!

 

That all depends your definition of easy.

I know people that would need a video and lots of pictures to figure out just how to unplug the connectors.

Others would have no idea where to even look for the ECU .

 

ECU's rarely go bad unless it's had water damage. Did you submerge your truck at any time?

Reman'd or a used one from the junk yard should do the trick for way less. Most yards have a return policy as well or warranties so you can return it if it doesn't fix the issue.

However, like Scope said it may not even be the ECU. Could be bad wiring somewhere along the way from the sensor to the ECU. Problem is you have to rip the engine apart to check it. You could take it back to the shop where you had it fixed and ask them to fix it again since the CEL came back and they didn't do the job right. You shouldn't have to pay anything more if they are an honest shop.

 

I'm not there, and I hate to bad-mouth any mechanic without knowing the details, ...

It sounds like you brought it in, they read code 52, and like a few on this site immediately conclude "Duh. Put in a new knock sensor." Which, of course, didn't make the code go away. So applying their diagnostic skills, they say "Duh, the code didn't go away. It must be a bad ECU." Which, alas, is just about the least likely option.

I'd be surprised if this shop is going to do anything when you take it back. They may have guaranteed that they replaced the knock sensor correctly (it's not hard), but they didn't guarantee that would make the code go away.

If you can find a junkyard that will let you return an ECU (I wouldn't, if I ran a junkyard), by all means give it a try. It sure won't be the first time I was wrong. But DO let us all know if that works.

 

You should come up to the junk yards in the Sacramento area. It's way more relaxed up here than the Bay! They will let me return anything if I have it "marked" hehe.

 

The ECU is behind the passenger kickpanel under the dash. Once you get the cover off, it is just 3 bolts that hold it on and 3 plugs. You didnt say if it was 22re or 3.0 but doesnt matter as far as what you are experincing with exception of ECU. Part number is on the ECU.

I have never had a bad ECU and is the very last part I would suspect failing. There is always a chance of one being bad. They are rugged but not water proof. Only ones I have seen bad were flooded. I would use a junkyard one myself.

Not criticizing you, but with what I see about sending it to shops for this issue and cost, I feel you have very little experience on these. My bet is it is the wire to the Knock Sensor. Dont think I have ever changed Knock Senors come to think of it, they are rugged. Get a Haynes Manual, it is what I use most. I have the Factory Service Manual and you can find one on ebay occasionally. Got mine for $30, and I use it very little. Only for in depth trouble shooting and even the FSM says it is for the advanced users.

Only having the truck for a year, I would do a complete tuneup using quality factory parts. Parts store quality is not the best lately. You can get factory parts off of ebay for alot less then the dealer.

Use a paper clip for the picture below and see if there are any other codes. TE1 to E1. Look at other areas that can cause a knock senosr to get activated. Bad timing, poor fuel, carbon build up.... How are your vacuum lines? Replace and route correctly with good ones. Clean the carbon out of the Plenum and on the ports and hoses. Do the Seafoam treatment. Clean the other sensors while at it.

Also check the connector to the ECU and see it is just needing reseated. I really dont think you have an ECU problem, but if the dealer says you do, they will have better means of checking.

I clear the codes by removing the battery cable for about 10 minutes and see if it comes back. On a 22re, this is fairly easy to do and if you have some mechanical experience is nothing to be worried about. Other then tune up parts, is not very expensive to do. I would only remove the Plenum if you decide to do this yourself. The following 2 pages will show what you are getting into.>>> https://www.yotatech.com/forums/f199...l#post52146627

Codes... http://4crawler.com/4x4/CheapTricks/...es/index.shtml

How to get Check Engine Codes. I just put this up for others. Applies to 87 and up. 86 and older is the bottom picture.


The Diagnostic port for the 85-86 is on the Drivers side inner fender and is nothing the same as the 87 and up. Here is T1 and E1 jumped. The codes and engine flashes are the same as the rest of the trucks on the dash.


Codes...http://4crawler.com/4x4/CheapTricks/...es/index.shtml

http://www.youtube.com/watch?v=9qEQM...ature=youtu.be

 

Lots of code 52 tech in here. I haven't experienced it myself, but did point this forum out to a friend who had a persistent code 52. Was the pigtail, and poor grounding. Of you do end up needing a new ECU, go junkyard. I got my spare/backup for $20. Guy didn't know what it was, so I offered $20, and took it. Go by part number.

Sent from my NSA screened iPhone

 

While setting the timing, using the right octane, and having good vacuum lines are all important, it's worth noting here that they have nothing to do with code 52. Code 52 does NOT mean the engine is knocking.

Instead, the ECU is constantly advancing the timing until the knock sensor reports knocking, then the ECU backs it off a hair. Resulting in optimally advanced timing at all times. Even if you were using 60 Octane gasoline! (If you could get it.) But if the knock sensor stops reporting (here, probably due to a wiring issue), the ECU could keep advancing the timing until the un-reported knocking blows a hole in a piston. So to protect the engine, if the ECU stops hearing from the knock sensor, it retards the timing and throws code 52.

Having a clean plenum is a good thing (and once it's off to replace the pigtail, you should take the opportunity to clean it anyway), but it won't help Mauk's problem.