# good source for ecm



## Windows on Wash (Aug 30, 2011)

I would start on ebay and then https://www.car-part.com/


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## ron45 (Feb 25, 2014)

What type of vehicle do you have.?

Reason asking.

My pickups don't have to go through emissions.
When you hook a scan tool to the vehicle it will say this vehicle doesn't support...

Now I pay more at the MV.


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## HotRodx10 (Aug 24, 2017)

You might look into how the memory in the ecm is powered. You may just need to replace a button cell battery in it, or check the battery power wire to it.

If you do need an ecm, by far your cheapest option is a pull-it-yourself salvage yard. If that isn't your thing, but you want to keep it reasonable, search for salvaged ones at partshotlines.com.

Not sure how old your truck is, but ecm's across the board have been fairly reliable since the early 2000's, but some before that were prone to problems, mostly due to components that didn't handle vibrations well.

From your description, I'd be willing to bet it's just the memory losing power, though, which should be easy to fix.


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## chandler48 (Jun 5, 2017)

Is it a diesel or gasser? My Cummins ECM has gone south, and the first indication is the "Wait to Start" light does not come on. $700 is a deep bite for me to take. Be aware, too, some ECM's are VIN specific, so it may need to be flashed to your VIN.


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## carpdad (Oct 11, 2010)

It's 96 f150, EFI, MAF, obd2 and california emissions. 4.9, I6 and gas. In nj. I can pass with 2 "not ready" but all 5 is showing up. The "not ready's" are all emission related, oxygen, its heater, EGR, catalyst, secondary air. This truck ecm does not have its own battery.
Funny thing is, I did several drive cycles (according to the ford instruction), and my reader gave me a green light twice. But as soon as the car is turned off and several minutes pass, those not ready's come back. It's as if ecm is not remembering the drive cycles I did and the monitor signals it's been getting. Because I had twice of the green light I don't think I have mechanical problems with the parts. 

BTW, I just do some repairs and replacement and the actual mechanics of some of the parts are beyond me. 

Thanks for the replies and will check those sites. I found one as well, called "carcomputerexchange.com". Looks impressive. Anybody know this site?


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## HotRodx10 (Aug 24, 2017)

> The "not ready's" are all emission related, oxygen, its heater, EGR, catalyst, secondary air.


I know the oxygen sensor, in particular, has to get up to temperature before it reads accurately, so when you first start it up, it takes a couple minutes before the ecm gets readings from it. The others may be similar.

Still sounds to me like the ecm is losing power when the vehicle is turned off. Have you checked the fuse for the ecm battery power supply (the one that should be always on)?


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## Brainbucket (Mar 30, 2015)

Sounds like Memory power is not there. Check fuse #9 30amp fuse in the under hood fuse box.:vs_cool:


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## carpdad (Oct 11, 2010)

Thanks!! I was told (f150 forum) that this ecm does not have battery backup. It always loses the memory if battery is disconnected. All these years I didn't think twice about it, just drove and never had trouble with computer. Just this time, inspection time got mixed with the virus delays, and the d..n gov't what were they thinking...bunching 3 months worth of inspections into one month, it seems.


First time learning about memory power circuit (right name?) as well as "always on" power about the car. Those are concrete leads that even me can follow, I think:smile: Will check those and if worst comes, it looks like rockauto is a source that I can deal with. I am somewhat familiar with it and the customer service was above the online chaffs. There are prominent auto computer sources but the reviews are mixed. If must, I will go to the dealers. This is one part I can't skimp on and I want to keep this truck. Never thought i'd get attached to a car.:smile:


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## ron45 (Feb 25, 2014)

carpdad said:


> It's 96 f150, EFI, MAF, obd2 and california emissions. 4.9, I6 and gas. In nj. I can pass with 2 "not ready" but all 5 is showing up. The "not ready's" are all emission related, oxygen, its heater, EGR, catalyst, secondary air. This truck ecm does not have its own battery.
> Funny thing is, I did several drive cycles (according to the ford instruction), and my reader gave me a green light twice. But as soon as the car is turned off and several minutes pass, those not ready's come back. It's as if ecm is not remembering the drive cycles I did and the monitor signals it's been getting. Because I had twice of the green light I don't think I have mechanical problems with the parts.
> 
> BTW, I just do some repairs and replacement and the actual mechanics of some of the parts are beyond me.
> ...


Are you sure its an OBD ll and not an OBD l.?
It should be exempt from modern day emissions.?


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## carpdad (Oct 11, 2010)

1996 and definitely obd2. It has obd2 plug also. It is first gen obd2. It helped a lot in past with diagnosing some problems. I think the ecm needs replacing. It's now throwing p0174 DTC which seems to indicate it needs a ventilator.:smile:


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## HotRodx10 (Aug 24, 2017)

The DTC code could be a symptom of the ecm losing power (and all the air/fuel mixture settings).

Have you verified that the ecm has permanent power to it from the battery? I don't mean to nag, but I'd hate for you to spend a big chunk of money on a new ecm and have the same problem.


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## carpdad (Oct 11, 2010)

None taken as unnecessary question.:smile: Thanks for staying with me. Question about power to ecm and the "always on power" is new to me and I haven't checked anything yet. In fact, I'm little tired of looking at the car. Put in about 500 mi and about that many drive cycles and 3 failed inspections.:smile:
I will be searching how to deal with ecm power harness and which pins to check for which voltage, etc. F150 forum has one guy who has an encyclopedic knowledge on my f150, bronco, and am depending a lot on the knowledge he organized.
After checking the ecm power, I also need to check all of the parts around the vacuum. I admit I didn't touch anything I couldn't readily identify, such as all of the vacuum tubes. I just learned there is something called vacuum reservoir as well. 

As such, I am closing this question. Again, thank you to all replies. I may have to do some extensive searching before I feel comfortable diagnosing the parts and/or replace.


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## HotRodx10 (Aug 24, 2017)

Before you put too much effort into poking around with the multimeter, find the fuse for the ecm battery power (should be labeled something along those lines). That's by far the most likely point of interruption, and the easiest to check.


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## ron45 (Feb 25, 2014)

When was the last tuneup.? If it's been a long time and you wish to keep it, I would start here.

How old is the 02 sensor.? Maybe clean it good and see if it makes a difference, if so replace it.

You might not need to go any further.


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## Windows on Wash (Aug 30, 2011)

Maybe run some fuel injector cleaner...?


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## carpdad (Oct 11, 2010)

Fuse: searching for the info on where, what and how. Also there may be a relay for it as well.

Tuning: forgot about it for while.:smile: Will do.

Additive: Been using lucas (it because it is something like soap and gentler on o rings than others) but been reading that techron is superior. May try it.


Thanks for the replies. I have neglected the truck. It's been running all by itself for many years and took it for granted. But it is 1996 and it's about time for tlc. Vaccum especially. I'm just finding out that vacuum doesn't mean just the hoses. It could involve the gas tanks, gas filler neck, gas cap, vacuum reservoir, just for starters. Either I find a mechanic familiar with this year f150 or cars, or diy, but it probably will take some time to learn these things if diy. I realize it's not a rock science but kind of daunting for a newby. I have haines and I may have to buy alldata for year specific info.


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## Brainbucket (Mar 30, 2015)

Get a library card as the library has Mitchel Prodemand, Aldata, Identafix I believe.:vs_cool:


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## ron45 (Feb 25, 2014)

carpdad said:


> 1996 and definitely obd2. It has obd2 plug also. It is first gen obd2. It helped a lot in past with diagnosing some problems. I think the ecm needs replacing. It's now throwing p0174 DTC which seems to indicate it needs a ventilator.:smile:


I don't want to confuse this situation and this may not be related.
But I find this situation odd and maybe somebody here can explain it.

carpdad said the truck is "" It's now throwing p0174 DTC""

This is a four digit code and usually relates to a V-engine not a straight or inline six.










The Haynes Techbook Automotive Computer Codes book

Has the 95 motor using three digit codes. (1992 to 1995)

O=Key on, Engine off. C=Continuous Memory;R=Engine Running

Code 174 (test condition C) Heated oxygen sensor switching slow right side

Which one is it.?


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## carpdad (Oct 11, 2010)

Don't know, though not a question for me. My truck is 96 f150, 4.9 manual I6. That much sure of.:smile: My reader is innova and cheapest. Codes but no words. I changed the oxygen sensors before but forget why. I changed them because I had MIL. This time, problems began with ecm not storing the KAM. Then I get p0174 while idling in the inspection line. About 20 min and hot day. It is DTC at this point. Also p0171. 

Search says this is both banks are lean. Causes can be anything from fuel regulator, pump,filter, vacuum to broken ecm. Does seem to be lot of this code.


I don't know why ecm problem and/or these codes. At the f150 forum, I got 2 opposing opinions as well, one ecm fine, another ecm broken. Both of history at the forum and I respect them.


So instead of just assuming a broken ecm, I am starting with emission related parts and the vacuum. But I really should check the ecm power first.:smile: I just don't want to look under that hood right now.:smile:


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## carpdad (Oct 11, 2010)

Truck fixed and inspection passed. New pcm from rockauto.:smile: Pcm harness kam power and the grounds checked all good. Baby step instruction from "hagerty.com" for voltage drop, invalueable. My obd2 reader was telling me the emission monitors were all ready, but the old pcm had no kam and throwing codes that would disappear next drive cycle. Nothing pending. I just decided to throw a new pcm at it and see what happens.:smile: The readings I was getting were intermittent and kind of crazy. It didn't feel like a good computer, based on little I experienced with my old desktop. 



I still have egr not ready but that passes in nj, this year cars. Not sure why but other drive cycle instructions have one clear difference from what I was using. That is go to 60 or so and coast to nothing without using brakes. That is one thing I didn't try. If no, then dig into egr system. 



Anyway, final thanks to all help.


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## HotRodx10 (Aug 24, 2017)

Glad you got it working! Too bad it wasn't something cheaper, but at least it's fixed.


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## Windows on Wash (Aug 30, 2011)

I think we have covered this. This was the fix in the bottle all along.


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## carpdad (Oct 11, 2010)

You're fairly insistant on the injector cleaners.:smile: Too late now but that gets me kind of curious about the fuel system. I will look into it and how it works within the emission systems. I wish there was a way to diagnose the old pcm but search says even the dealers will test by replacing with known good pcm. Still have the old pcm with me, and not returned for core change. Not sure what to do with the old one. Rockauto and return postage will not be cheap from nj. Probably not worth going to the post office. BTW, they are still closed, or at least, don't see any cars there now.


1996, so new injectors or at least cleaning and new o rings maybe justified, but I'm not sure if I want to go there as a diy. Would involve at least removing upper intake manifold and there is the saying, if not broken, don't fix, and it is esp true for this diy.


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