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One more time....How do you check ECU trouble codes on EA82?


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21 replies to this topic

#1 Brettm57

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Posted 21 September 2003 - 06:32 AM

I know it's been posted on here a thousand times, but how do I check the ECU trouble codes on an EA82? This is on a '92 Loyale with SPFI. I read the USRM instructions and found the LED in the ECU that flashes the codes, but I couldn't find the wires to connect together. If I'm reading the instructions right, they're under the dash, right? Can somebody give me the color of the connectors and wires? That might help. I did find some wires by the passenger side firewall (engine side) that looked like they could be it, but according to the instructions they shouldn't be there in this year car. Thanks in advance for your help.

#2 Skip

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Posted 21 September 2003 - 07:04 AM

On SPFI models they are found under the hood by the driver's side hood hinge.
the two set colors are White and green .

Hope this helps, Al has more info for you on SPFI checking if needed.

#3 Brettm57

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Posted 21 September 2003 - 07:29 AM

OK, so the wires under the hood ARE it! What combination of which wires gives me which codes? I tried hooking the green connectors together, and with the key on I got some kind of a snapping noise on the right side of the firewall. Any idea what that is? Also, just to double check, will the code flash out through the LED I found in the ECU with the key on, or is it through the "Check Engine" light like a Legacy? And last, who's Al?

#4 86subaru

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Posted 21 September 2003 - 10:34 AM

my wires were already connected, look below the steering wheel and you should see a red blinking light , if there is something wrong , the light is pretty small and red , short and long blinks :wave:

#5 asavage

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Posted 21 September 2003 - 11:05 AM

Originally posted by Brettm57
OK, so the wires under the hood ARE it! What combination of which wires gives me which codes?


(Here's the article that Skip posted on checking codes and code meanings.)

I tried hooking the green connectors together, and with the key on I got some kind of a snapping noise on the right side of the firewall.

That's a relay that cycles every two seconds. It's normal in D-check mode.

(Warning: some of the below may not be correct; I'm writing this off the top of my head, and it's not straightforward stuff.)

There are at least three modes:

* U-mode: no connectors connected, this is the condition you drive around in. The Check Engine Light ("CEL") tells you that you need to check for some codes. No CEL = only intermittant codes might be stored.

* Read Memory: (Loyale: white connectors connected) On later (some models, about post-85??) ECUs, there is some RAM to store intermittant codes. Check for these by connecting the white Read Memory connectors.

* D-mode: (Loyale: green connectors connected) use this for setting ignition timing, and for running the diagnostic procedure, which purposely tests all sensors and switches in the emissions system, over the course of two minutes, but you have to do specific things, and there are a couple of things to avoid doing during this procedure. D-mode will set new codes, which will then have to be tracked down.

If all you're going to do is check codes for existing hard codes, you don't need the D-mode (green) connector.

(It's important that, if you are going to run the D-mode test procedure, that the engine is warmed up. I am not including the D-mode procedure here.)

To check for existing codes, you check in two modes:

a) with no connectors (U-mode)
B) with Read Memory connectors (white ones, next to green ones, next to the fuel filter on the left shock tower on Loyales) (Read Memory mode)

Any idea what that is? Also, just to double check, will the code flash out through the LED I found in the ECU with the key on, or is it through the "Check Engine" light like a Legacy?



No, the CEL will not flash codes on the Loyale series. It will come on (to indicate a hard code, that can be checked in U-mode via the O2 LED), and it will only flash in one case -- and you won't see that in any mode except after completion of a D-mode test (and the flashing does not indicate a code value in that case anyway).

Loyale: the CEL comes on with key on engine off. If it doesn't, fix that first, because it's absolutely necessary for further code checks.

Next: If, with the engine running, the CEL light stays on or comes on, read the code(s) on the ECU's red O2 sensor LED. The codes will repeat, so no hurry, you won't miss any. You don't need have to have the engine running (but it can be) (edited: no, it can't be: if the engine is running closed-loop (warmed up), the O2 LED will monitor O2 transitions in U-mode, not output codes. Must be Key On Engine Off to read codes in U-mode), and the engine does not need to be warmed up for this U-mode check -- NO connectors need to be connected at this point.

If you don't have a CEL light with the engine running, you probably have no U-mode codes, and when reading the O2 sensor LED you'll get a sequence of short flashes only, repeating. (with key on engine off). My '93 Loyale, non-Calif, 4WD, gives seven shorts flashes for the Processor ID. Confused yet? The range of possible Processer ID values is around three to eight, I think. Again, you will only get this sequence of short flashes if you have no U-mode codes set.

Next, you can read stored intermittant codes, the ones that come and go, and cause the CEL to come on but later go off. Do this by connecting the Read Memory connectors with engine off, then turning on ignition (Loyale: white connectors next to green D-mode connectors, near fuel filter on left shock tower). Read codes the same as in U-mode.

All codes start with a "tens" flash, so if you are only getting short flashes, you have no codes. If you get a long flash at any time, then there is a code stored, and that's a code tens digit. Count the long flashes, then count the short ones that follow, and add them up: three long followed by two short is 32, which is an O2 sensor fault. Etc. Use Google to find a code listing chart for your year, there are several.

If there is more than one code, there will be a pause between the first and subsequent codes. At the end, they will all repeat, and continue to repeat as long as the key is on.

Once you fix the cause for those U-mode codes, you can reset them by connecting BOTH the D-mode connector AND the Read Memory connector, then running the D-mode diagnostic. Forget about even trying this until you've found the cause of the U-mode codes, because they won't reset until you fix them, period.

Hope this isn't too confusing. If it is, I can't help it -- it's the early Subaru way, and I don't do my best tech writing B4 breakfast.

#6 Cougar

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Posted 21 September 2003 - 11:14 AM

The sound you heard was relays closing I beleive that are in the test sequence.

The flashes are seen looking at the LED in the ECU unless there has been a change from my '88 model.

I think Skip was refering to Al Savage, who is a poster here and has a 93 Loyale.

EDIT: Opps! I see Al has now posted ahead of me so no introduction needed.

#7 Brettm57

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Posted 22 September 2003 - 08:04 PM

Al, I'm thinking that my CEL doesn't come on. I say think because the battery is dead and my charger quit working so I can't check it out right now. Yeah, I'm mad! I don't remember it coming on with the key though. Anyhow, if my CEL light doesn't come on with the key on, what could be wrong with that? And how does that tie into the rest of the system as far as troubleshooting? I pretty well understand the rest of what you wrote, and I appreciate it. Maybe I can get this thing straightened out yet!

#8 Cougar

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Posted 22 September 2003 - 09:37 PM

Recently Al found a problem in his ECU circuitry that controlled the CEL light. There is a transistor array pack in the ECU that has 4 transistors in it that control different things and one of them, that controlled the CEL light, was bad. He replaced the bad section with a single unit as the other three were ok. The transistor makes a ground connection that turns the light on when called on by the ECU and in the test mode when the ignition is turned on.

If this is a problem with your ECU also let us know. I have some of the IC's to replace the original unit. It would be good to check the bulb also to see if it is ok. The other choice is to replace the ECU at a pretty high cost unless you can find a deal somewhere.

#9 asavage

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Posted 22 September 2003 - 11:17 PM

Yup, Glen described my situation pretty well. I covered the step-by-step (sorta) here.

(Man, it's like pulling teeth, to get a specfic post ID number from this system -- I had to go read the source.)

Key On, Engine Off, the CEL should light steady. On my '93 Loyale, it's on the lower right end of all the red lights under the instrument panel.

If it does not light, I think that it may be easier to put a voltmeter on the ECU connector to which the CEL is connected, and with the key on, see if that pin is near 12v or near ground. If near 12v, the ECU is defective -- or, most likely, the transitor driver array uPA1478H is bad, like it was on mine.

I do not have the wiring diagram for that circuit with me right now, but if you want to do this check, post back here or email me (asavage at iname dot com) before 6am PST and I'll get you the ECU harness pin number and color code of the wire to check for your '90 Loyale Turbo.

If you want to try to fix the ECU (and the engine does run), you can replace that uPA1478H with one that Glen will sell you, if you are comforable with desoldering through-hole plated PCBs. If not, you can take the ECU and the new part to pretty much any TV repair shop and have them do it.

I didn't go that route: the CEL driver is only one-fourth of that uPA1478H, so I found a single-transistor replacement, snipped three leads off the uPA1478H, and grafted my transistor to them. It's still working (and tonight I got around to paralleling a second (yellow) LED to the red one. Mine's on a coax jack and 6" lead, so I could watch it blink while driving home, though I did have to watch it between the steering wheel spokes, which isn't too safe.).

If my crappy digital camera would do any kind of decent focus for shots <4', I'd have taken some nice pics. Unfortunately, it won't (anybody wanna buy an Olympus D380 with orginal box/accys/charger, w/128MB card for cheap?).

Lastly, you can send me the ECU and I can do either repair (graft-on driver or replace the uPA1478H with Glen's). No charge, you just pay shipping and buy the part.

So, the no-CEL can likely be repaired.

Replacing the entire ECU is another idea. The thing (for your car) can be had for as little as $50. Use http://www.car-part.com/ to see where.

On mine (93) there were three different ECUs available in that year, and the cheapest I could find was for something like $150.

#10 Brettm57

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Posted 23 September 2003 - 05:41 AM

It's now 6:35 AM, and I have to go do a job. As soon as I get home (late afternoon), I'll jump the battery in my car and check the CEL. I'm thinking that it doesn't light up until I actually start the car. Does this mean anything? Thanks for your help guys, I appreciate it.

#11 Cougar

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Posted 23 September 2003 - 10:09 AM

The light is there to tell you that a service code has been set in the ECU memory, when the light is on while running. You then need to look at the ECU's flashing LED, count the long and short flashes, to find out what code(s) has been set in memory so you can locate the trouble area.

Things that set off ECU codes effect the engine performance. There are still a lot of things that can go wrong that are not monitored by sensors to the ECU and will not set off any codes.

Your welcome for the help on this. We learn also by doing this and, there are some really sharp trouble shooters here on this board.

#12 asavage

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Posted 23 September 2003 - 02:51 PM

I can't post a pic right now, but I have the CEL/ECU info.

The ECU has three wiring connectors. On mine, they're yellow plastic. One of them has 12 pins. One of the two wires nearest the lock latch is Red w/Yellow stripe: that's pin 40, and it's the CEL lamp ground.

For the following test, you'll need to drop the ECU down. It's behind the knee bolster under the steering wheel. Remove knee bolster (several screws). The ECU is retained via three 12mm head nuts, and the ECU mountings are slotted. Supposedly, you can just loosen the three nuts, and pull the ECU toward the rear of the car, but I've always had to remove at least the rightmost nut completely.

Once down, locate Red/Yellow, straighten a paper clip and insert it into the back of that pin. Connect a voltmeter's red probe to it -- a clip lead works best, but use what you have. Connect the black voltmeter's probe to a good ground.

Measure that pin 40 with Key On Engine Off:

a) if 12v or close is present, ECU is bad.
B) if 0v or close is present,
* CEL lamp is lighted, or
* CEL lamp is bad, or
* no power to CEL lamp

If B), I can get wire color for lamp feed, but one step at a time: check that voltage.

#13 Brettm57

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Posted 24 September 2003 - 08:57 PM

OK, I've got my battery charged up, and the CEL is working like it's supposed to. I hooked up the white leads, turned on the key, and I get number 35, a bad canister purge valve. Life is good! I found the vacuum lines crossed going to the purge valve, and I'm hoping that was the problem. If not, I'll replace the valve. Now, can you tell me how to clear the computer after it's fixed? Maybe this job is finally winding down. I've got to thank you guys again for your help on this, I don't think I would have ever figured it out on my own.

#14 asavage

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Posted 24 September 2003 - 11:12 PM

Originally posted by Brettm57 . . . I get number 35, a bad canister purge valve. Life is good! I found the vacuum lines crossed going to the purge valve, and I'm hoping that was the problem. If not, I'll replace the valve.


Based on what I've read, and my bad one, you will find that the solenoid's coil is open.

Use a ohmmeter, remove the PCS connector, and check the solenoid's resistance. Should be ~35 ohms. It will read infinity (open). Coil is bad.

Bad news: dealer wants over $110 for it.

Good news: it's the identical unit as the EGR solenoid that sits right next to it, with the exception of the wire connector. You can get one from a junkyard or wherever and cut off your old connector, solder it on to an EGR solenoid, and it fits perfectly . Bolts right in place, hose connections are identical and everything.

And, I have a local source for a few new EGR solenoids. Call A&G Import Auto at 360.385.0002 in Port Hadlock, Wash., ask for Tony, and he'll set you up for a lot less than $110, and all you have to do is solder two wires. Mention Al Savage and he'll only jack up the price another $10 (for my cut, you understand :-p ).
I did this myself last week, and posted about it here.

Now, can you tell me how to clear the computer after it's fixed?


You're supposed to run the D-check procedure. Warm it up, shut it off, connect both the D-check green connectors and read mem connectors.

(edited later: I left this part out: Turn on the ignition, verify that the CEL light comes on, press accelerator to floor, then back off to half throttle for two seconds, then release it completely.)

Then drive it constantly above 5 mph for at least 39 seconds (yeah, I know). CEL is supposed to blink, indicating no codes found.

If, after about two minutes of driving above 5 mph, you get the CEL light again and it's not blinking, it's done with the diagnostic mode and it found another code, which you can then read. On my rig, I sometimes get a 51, Faulty Transmission Inhibitor Switch. Balls -- switch tests fine. Maybe it's intermittant, but it's sure no fun to get out and work with: I've done it once.

#15 Brettm57

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Posted 25 September 2003 - 05:32 PM

It's fixed! I found a similiar canister valve on a '85GL car I've got and replaced the offending CPV on my '92 with that. I also left the battery unhooked overnight, hoping that would clear the computer. Apparently it did, because the CEL stays off now. I let it run for about ten minutes and it didn't light up. It did light up after a couple of minutes after leaving the battery unhooked overnight.

Finally! It's beer time!

And again, thanks for your help.

Now I fix the brakes.... Oh boy!

#16 ShawnW

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Posted 25 September 2003 - 05:50 PM

Hey everybody the USRM is still around it is just being Rebuilt.

It is here now:

Ultimate Subaru Repair Manual

Also found by hitting the USRM button at the top of all the board windows here.

So your article is now here:


http://usmb.net/repa...e9.39782181.art

#17 brat1709

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Posted 29 September 2003 - 12:51 AM

By far, this has been the best post I've seen , regarding ECM Codes. I've been able to locate data on how to read codes, but nothing on location. I hope you post this article on USRM. As a matter of fact, I would love to here where the location of the wires. I had no idea that on some models, the wires where located on the LT fender region. I even took a 1987 Subaru SW to a local mechanic, and the guy said he could not find the wires under the dash. As a matter of fact, he spent a long time, and even removed the ECM. He even said someone had tampered with the vehicle. I'd appreciate all input in regards to the test connectors location, colors, and step by step directions of how to appropriately conduct the code test. This article by far, has had the most information I've seen. Many thanks to all in advance.
Hugo/So. CA:banana:

#18 Brettm57

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Posted 29 September 2003 - 04:08 PM

When I first called a dealer about this car they told me I had to have a scanner to check the codes, there was no way to do it in the car. I figured out from the service manual that it could be done, but it didn't give enough info to figure out how to do it. Thank God there's people like the ones writing in here to help the rest of us. I've already run off a hard copy of this to keep in my service manual. I was fairly sure the wires were the ones by the master cylinder based on the wiring diagram, but my service manual said that the wires were under the dash. The good news is my car is fixed now.

You're right, this would make a great article for the USRM.

#19 asavage

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Posted 29 September 2003 - 09:35 PM

AllData is specific for my '93: the "Read mem" connector is under the dash.

Bollocks. I read the wiring diagram color code, then found them right next to the green D-check connectors, next to the fuel filter.

Snap-On's manual for their scantool is ambivalent, it shows both locations, but the Subaru section has about nine different location diagrams for various models and years.

#20 brat1709

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Posted 30 September 2003 - 03:25 AM

I agree with Brettm57. This is by far,one of the best descriptive articles that helps one test and find the test connectors.....

I'm also more interested in anyone knowing any other books that involve wiring diagrams specific to Subaru.

By the way, does anyone have the wiring diagram for a 1987 and 1988 Subaru wagon with spi. I'd be interested in the Factory Service Manual, if available.
Hugo/So. CA

#21 Houston505

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Posted 15 July 2014 - 02:25 PM

Great info! I tested my 92 Loyale EA82, and it came up with a Purge Control Solenoid Valve code. Now, do I have to buy a new evap canister, or can that valve alone be replaced? Also, will that itself, or the fact that it's throwing a code up, make the engine run any differently?



#22 Houston505

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Posted 17 July 2014 - 03:54 PM

Based on what I've read, and my bad one, you will find that the solenoid's coil is open.

Use a ohmmeter, remove the PCS connector, and check the solenoid's resistance. Should be ~35 ohms. It will read infinity (open). Coil is bad.

Bad news: dealer wants over $110 for it.

Good news: it's the identical unit as the EGR solenoid that sits right next to it, with the exception of the wire connector. You can get one from a junkyard or wherever and cut off your old connector, solder it on to an EGR solenoid, and it fits perfectly . Bolts right in place, hose connections are identical and everything.

And, I have a local source for a few new EGR solenoids. Call A&G Import Auto at 360.385.0002 in Port Hadlock, Wash., ask for Tony, and he'll set you up for a lot less than $110, and all you have to do is solder two wires. Mention Al Savage and he'll only jack up the price another $10 (for my cut, you understand :-p ).
I did this myself last week, and posted about it here.



You're supposed to run the D-check procedure. Warm it up, shut it off, connect both the D-check green connectors and read mem connectors.

(edited later: I left this part out: Turn on the ignition, verify that the CEL light comes on, press accelerator to floor, then back off to half throttle for two seconds, then release it completely.)

Then drive it constantly above 5 mph for at least 39 seconds (yeah, I know). CEL is supposed to blink, indicating no codes found.

If, after about two minutes of driving above 5 mph, you get the CEL light again and it's not blinking, it's done with the diagnostic mode and it found another code, which you can then read. On my rig, I sometimes get a 51, Faulty Transmission Inhibitor Switch. Balls -- switch tests fine. Maybe it's intermittant, but it's sure no fun to get out and work with: I've done it once.

 

Is the pressing the accelerator down before or after plugging the two connectors together?






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