CEL does not (ever) come on: normal?

[asavage]

I'm chasing a driveabilty issue.

 

My '93 Loyale (A/T) has a Check Engine Light on the lower right of the instrument cluster. I do not have an Owners Manual. My Alldata reference CD strongly suggests that, under normal conditions, this CEL should light with Key On, Engine Off (KOEO) (without D-check or Read-Mem connectors connected: that is, normal driving setup).

 

Well, mine doesn't. I'm playing with a SnapOn Scanner (scantool) MT2500 and cursing it (because its onboard directions do not remotely match the paper instructions), but it also implies that the CEL light should come on in KOEO mode.

 

I've backprobed the ECU -- actually, it's now sitting on the workbench in front of me, but I did a ground check on the appropriate circuit (Pin 2 of the center/18-pin connector, Red with Blue stripe) and it does not provide a ground at KOEO.

 

So . . . do I have a faulty ECU? I need someone who owns a similar year/model to check that the CEL comes on with Key On, Engine Off (without playing with any connectors whatsoever).

 

Thanks in advance. Email to asavage@iname.com if convenient, cc here of course.

[DerFahrer]

That's right, all lights on the dash should light up in "KOEO" mode. If not, the bulb has probably burned out :cornfuzz:

[asavage]

Originally posted by subyluvr2212

That's right, all lights on the dash should light up in "KOEO" mode. If not, the bulb has probably burned out

 

Not on mine

 

I've swapped the CEL bulb with the Brake Fluid Level bulb, they're both good. The ECU is not providing a CEL lamp ground -- I checked. Sigh.

 

Looks like I'll have to round up an ECU.

 

ECU 22611-AA397 (from 9/92 thru 1/93)

 

Plenty of used ones available:

http://www.car-part.com

Cheapest listed is $45, and it's on the wrong coast. And I'm seriously short on budget right now.

[Cougar]

Hi Al,

 

The CEL light should come on in the KOEO mode as a test to let you know that the lamp is ok. Hopefully the bulb is burned out or there is a bad connection to it. If things are ok there then you may have a bad circuit in the ECU. I have in the past replaced an IC in a ECU before for that reason. The ECU light would not work.

 

We have to do emissions tests here in Anchorage and if the lamp doesn't work then you are done with the test until it is fixed.

[asavage]

Yes, this ECU has a one-quarter-failed NEC uPA1478H.

 

Base = pin 8 (5v drive from somewhere else)

Collector = pin 9 (to CEL lamp)

Emitter = pin 10 (tied to ground)

 

Base drive voltage toggles fine, but the C-E junction doesn't ever pass current. With open collector, I see base voltage less .3v at collector. Looks like a bad part to me.

 

Unfortunately, I don't find a ready source for the part. I could call around on Monday, but I'm going to try to replace that one-fourth with a discrete transistor instead. Circuit design isn't my fortè -- I usually just fix 'em, I don't try to re-engineer them -- so I've posted the relevant info over on Usenet sci.electronics.repair, and I hope that someone over there will point me to a generic transistor that I can pull out of my junk bin and solder in.

 

Unless someone's got a spare ECU from that era laying about from which I could rob that part? Would likely need to be a 26111 series ECU, but I doubt that it matters what the last five characters after that are, they probably all use the same part for that circuit.

 

For reference only:

Datasheet picture (PNG format, with my scribbled-in circuit notes) here:

 

http://www.ncplus.net/~asavage/Subaru/uPA1478_01_.png (77k)

http://www.ncplus.net/~asavage/Subaru/uPA1478_02.png (37k)

 

Or, if you prefer JPEGs:

http://www.ncplus.net/~asavage/Subaru/uPA1478_01_.jpg (147k)

http://www.ncplus.net/~asavage/Subaru/uPA1478_02.jpg (74k)

 

(Original NEC datasheet:

http://www.necel.com/nesdis/image/IC-3566.pdf (59k) )

[Cougar]

Hi Al,

 

I worked on one of these ECU's for the same problem about 6 years ago. I sent away for the IC's and I remember I had some extras because I had to order a minimum of fifty dollars in parts. Digging through the many pieces of paper and other things in my desk I found the other three IC's I had left from the repair order. If you want, I'll sell you one of them for fifteen dollars and you can pay me later when funds are better for you. I could send it to you Monday if you want. Thanks for the link to the data sheet. I printed a copy out to keep with the IC's as I did not have one before.

 

Nice job of trouble shooting this problem Al. You obviously know electronics pretty well. You stated previously that you were short on funds. With the kind of skills you have it seems you should be working somewhere that would be willing to pay well for your kind of talents. I grew up in Seattle and I know Port Townsend isn't a real big place to find work though it is sure nastalgic with the old fixed up Victorian homes. Do you work in the local area?

[asavage]

One problem/advantage of network-based interaction is that you get to make up all kinds of stuff .

 

The job I've had that I liked best was an electronics bench tech for two years, computer monitors & terminals. Until about five years ago, you didn't need to know much . I own a TDS-210 'scope that I bought new, a Pace desolder station, Fluke 23 & 79s, and the usual complement of assorted junk, all of which mostly sits in storage these days -- I am not really educated enough to do commercial-level electronics work, and you can't make a living fixing the consumer crap anymore -- six years ago, my average repair cost for a monitor or terminal was $110; nowadays, it's like a broken VCR: you don't repair it, you toss it and buy a new one.

 

Being able to find an open junction on a part that drives the CEL lamp is a non-paying skill. I can only call it a hobby and write off my time as such; nobody in the North Olympic Peninusula is going to pay me to do this kind of work, and I'm not moving to Portland or Seattle to chase a job that has probably already been outsourced to India, Pakistan, or Korea.

 

==========

 

A kind soul on sci.electronics.repair decided that an NTE2338 would be a perfect fit:

 

http://www.nteinc.com/specs/2300to2399/pdf/nte2338.pdf

 

and it looks good to me. Not only that, but a cursory look through my junk bin yielded two (2S)D2018 parts, which cross to NTE2338, so I'm all set. The NTE part is under $2, but nobody within 70 miles of me stocks NTE parts; I'd have to drive to Bremerton to get it, or have it shipped.

 

I'm off to the storage unit to get out the Weller station and stereoscopic helmet and dust them off.

 

If this doesn't work, I'll take you up on your kind offer. Undoubtedly, replacing the uPA1478H with a like part would be the most professional solution, but the 2338/2SD2018 is an acceptable alternative for my own car.

 

Just for completeness, this is a:

 

1993 Subaru Loyale SW, 4WD, AT, A/C, mfgr'd 10/92

 

ECU: 22611-AA397 (from 9/92 thru 1/93)

 

Processor spec.: 7 (Fed/49 state, A/T)

 

Component ID: IC14

Component Part No.: NEC uPA1478H

[Cougar]

Hi Al,

 

I kind of figured you must of done some sort of trouble shooting for awhile. You have a good collection of tools also.

 

As far as repair goes; to the person who would have to replace the ECU instead of fixing it like you did, they would be facing about a three hundred dollar bill for a rebuilt ECU and labor to put it in. Not sure what you are doing currently but it seems a lot of auto repair shops need techs with good electrical skills. Going to component level repair of an ECU shows good knowledge in my book. It seems a number of shops have techs doing work on vehicles that have no idea what Ohm's Law is.

 

I think the alternate Darlinton device you have in mind should work nicely. Looks like you will have to turn it around to match the leads up. I'll still have the other IC's here if you need one. Let me know how it goes but I'm sure it will be no problem.

 

Glen

[Flowmastered87GL]

My 87 GL has NEVER had the light come on for any reason... somehow I think the bulb was yanked out... I never bothered to check however because since I removed alot of unnecessary parts to install the weber, I'm sure I would be getting all sorts of codes.

[asavage]

Originally posted by Cougar

I think the alternate Darlinton device you have in mind should work nicely.

It does!

Plugged the repaired ECU into the harness this morning, connected a test lamp to the dash connector (the lower dash is out, waiting for NAPA to get me a PC37 bulb/socket combo, as one of mine was missing), and KOEO the lamp lights. Start engine, lamp goes out. Almost as if it was designed to work that way

 

Originally posted by Flowmastered87GL

I never bothered to check however because since I removed alot of unnecessary parts to install the weber, I'm sure I would be getting all sorts of codes.

You must not have the GL licensed in Portland. I lived there for years, you gotta pass the smog test to get your tags every two years. Whatja do, register it in Newberg?

 

One nice thing about Portland, you can take the smog test for free, and as many times as you want (you still have to wait in long lines, of course). Lets the home DIYer do his own emissions repairs for cheap. Some tough cars I worked with, I used that resource a lot.

[Cougar]

Good work Al. You saved yourself a good amount of money over a rebuilt ECU.

 

Have you thought about a career in Automotive Electronics? You would do well and I think the pay for a top tech is very good income.

 

Best regards,

[Flowmastered87GL]

Originally posted by asavage

 

You must not have the GL licensed in Portland. I lived there for years, you gotta pass the smog test to get your tags every two years. Whatja do, register it in Newberg?

 

One nice thing about Portland, you can take the smog test for free, and as many times as you want (you still have to wait in long lines, of course). Lets the home DIYer do his own emissions repairs for cheap. Some tough cars I worked with, I used that resource a lot.

 

Its registered in The Dalles actually

[asavage]

First, the PC37 bulb/socket combo does not quite fit the dash. I trimmed the socket a bit with an Exacto, but it's not something I'd recommend -- buy the right part. I mention it only to prevent someone else from trying it.

 

Tonight, I got the ECU re-mounted in position, reinstalled the dash panel, and fired it up. CEL worked like it's designed.

 

After about two minutes, I finally got the CEL that I was looking for, so I levered myself down eyeball-to-eyeball with the O2 monitor LED, and read the code: 35: Purge Control Solenoid (PCS) continuously ON or OFF.

 

I see, from a Google Usenet ("groups") search that this is a very common problem.

 

I followed the Alldata diagnostic chart, and found the PCS' coil is open (should be approx. 100 ohms) [correction: should be 35 ohms, checked on one used and one new unit]. It's located just behind the water outlet housing/thermostat housing, bolted to the top of the intake manifold with one 10mm head bolt. It has two small vacuum hoses and one two-wire connector (GL = Green w/blue stripe, BW = Black w/white stripe). The BW wire should have near 12v on it with ign ON.

 

NAPA does not list this part, neither does Beck-Arnley, so I removed mine, put it in a Ziplock baggie with a note, and hung it on my local Subaru junkyard's door, so they'll find it tomorrow. Hopefully, they'll call me with good news, but it sure looks like I'll be better off buying a new one.

 

Thanks to all for your help and support. Now I'm off to start another thread or two.

[asavage]

On 9/6/2003 at 9:47 PM, asavage said:

NEC uPA1478H.

For reference only:

Datasheet picture (PNG format, with my scribbled-in circuit notes) here:

http://www.ncplus.net/~asavage/Subaru/uPA1478_01_.png (77k)

http://www.ncplus.net/~asavage/Subaru/uPA1478_02.png (37k)

 

Those links are long dead; the hosting service folded up over a decade ago.  I've attached images to this post; hopefully, they'll stick around longer.

[idosubaru]

1 hour ago, asavage said:

Those links are long dead; the hosting service folded up over a decade ago.  I've attached images to this post; hopefully, they'll stick around longer.

18 years later HOLY caterpillar liver Batman!!  Good work, those long years ago and sharing the specs here. Thanks.

I’m dying to know what happened to the car?!  Did it treat you well as how did you end up here 18 years later?

[asavage]

Oh, it wasn't ever really MY Loyale.

The backstory is that I was the 2nd AND 4th owner of an '82 Datsun (remember Datsun?) Maxima (formerly 810) SW with the LD28 DIESEL engine, which was the 240/260/280Z engine block modified to an Inline-Six diesel.  A very nice engine.

 

I'd bought it from the original family in Portland, Ore. around 1996?  When I was living in Bellingham, Wash. around 1999, I had two other diesels and three vehicles was at least one too many, so I sold the wagon to a co-worker.  Later, around 2003, his new wife wanted a Subaru, I bought the Loyale and was fixing up some things before swapping it for my old Maxima wagon again.

 

That's how I ended up working on that '93 Loyale.  They had two kids, split up in an ugly divorce, and I lost track of him and the Loyale.  Like so many things in life, I wonder where they are now.