CEL won't go off...

Got a solid CEL on my 1991 Legacy L AWD Wagon.

I've cleared the codes, then connected the Test mode connectors & got a steady blinking CEL - should mean no codes are stored in the memory.

 

So, next I disconnected the Test mode connectors and

the CEL just stays on solid.

 

I need to clear this up before taking it in for a CA smog test.

 

Please help with any ideas, solutions, suggestons...

 

KKMFT

You need to connect the read mode connectors to see the codes. Should be next to the green one's but they are black or maybe white. Connect them and turn the ignition on - then you will get the codes.

 

GD

OK, thanks for that

 

I connected the two black read mode connectors

 

CEL flashed these codes:

12 - starter switch

13 - cam angle sensor - CMP

21 - coolant temperature sensor - ECT

22 - knock sensor

23 - airflow sensor - MAF

32 - oxygen sensor

35 - purge control solenoid valve - EVAP

51 - inhibitor switch (neutral position switch)

 

code 51 seems odd -

Haynes manual relates this to an automatic transaxle, mine's manual...

 

otherwise the car seems to run really well, no hesitation, etc.

maybe the contacts to all these sensors & switches are bad??

 

any ideas??

Holy code soup Batman!

 

Well I would start with the easy ones, clear the codes, and see which one's come back.

 

21, 22, 32, and 35 are fairly common. I just worked on a '90 with 22 and 35 codes.

 

The original knock sensor's were flawed and they crack. Get the new one at the dealer - about $65.

 

Evap solenoid's routinely fail. Replace it with a 33 Ohm, 5 watt resistor. Gets rid of the code.

 

Test the coolant temp sensor - should be on the back of the manifold - passenger side. See if the resistance is within range for the temp or if it's open, etc.

 

O2 sensor should probably just be replaced if it hasn't been done - they get old and '91 is plenty old enough.

 

Then clear the codes and see what comes back. In my experience, once you fix most of the codes they just clear on their own.

 

I would also check the wireing harness over on the passenger side - a bunch of the stuff you are having codes for is connected over there behind the manifold. Make sure the wire to the O2 sensor isn't rubbing on the passenger side axle and that all the connections are clean and tight. That's a butt-ton of codes even for a high-mileage '91 and I wouldn't be surprised if there were wireing issues.

 

Oh - and the manual's still have neutral switches. It's on the transmission and the connector is right there behind the manifold like the O2 sensor, knock sensor, Evap solenoid, etc.

 

Also - Legacy's are technically "New Gen" and belong in the Newer Generation Forum. Just a reminder for next time. There's not as much Legacy knowledge hanging out in this section of the forum.

 

GD

whoa! that's a lot of great information! this will definitely push my experience level a bit, but I guess it's time to learn...

 

there are some rusty/corroded wiring harnesses - one near the fusebox behind the battery for starters, so I'm not surprised the wiring is suspect

 

thanks GD!!

Mix half a box of baking soda into a used gallon milk jug - pour it over the battery area to neutralize any battery acid in the area. Make sure you wipe up any splashes on the paint as the acid can eat into the paint. I like to pull the battery and tray and clean everything - wire brush, compressed air, and then some semi-gloss black. That will stop the nasty acid from eating up your battery shelf.

 

GD

thanks GD, that's helpful

 

last weekend I attempted to clear the codes & pulled the battery,

cleaned up the battery & the shelf, and painted the bracket

that's when I noticed the wiring harness in its questionable state

 

I'll use your baking soda recipe next weekend + your suggestions above & reply with the outcome - hopefully positive & simple to resolve

 

thanks for clarifying that Legacys are new gen...

my first Subie was an '82 GL 4WD wagon, it's long gone now though

 

I really appreciate your help

No problem. Amongst my collection is an '84 GL wagon - very similar to your '82 and was also my first. I've since expanded my collection to include like 6 generations of Subaru's. Funny how that works

 

GD

Oh yeah

I didn't mention the oil leaks on my '91

thinking I'll put in new valve cover gaskets & grommets at some point

 

I've been looking at RockAuto prices for all the sensors the codes refer to

and hope I get a lot resolved with attention to the wiring... don't feel like spending upwards of $500 just to make the CEL happy

oh yeah and it gets worse...

I didn't to mention the odometer quit at exactly 150k

I figure it has +/- 187k on it now

 

nevertheless I sure like driving it around, its a good commuter car

and helps me save the wear & tear on the '01 Bean -

(last month it got a new serp belt, pulleys, then an alternator)

Check the o-ring at the rear, passenger side cam access cover (it's actually a distributor mounting port cover but we didn't use distributor's here in the US). Those o-ring's get hard and leak. You can replace it at the same time that you do the valve cover gaskets and bolt grommets. It's just two 12mm bolts. Very simple. Those are the three most common oil leaks.

 

GD

With all the error codes you had I would suspect a problem with the power to them. They may have a common power source.

thanks

 

will you explain how to check this out?

Go over all the grounds, maybe even add an extra ground wire from the chassis to the engine block.

thanks

 

will you explain how to check this out?

 

To see if there is a power problem to the sensors you need to use a voltmeter and check the power lead going to them. To see if there is a ground problem measure the voltage on the ground connection of the sensor and the negative battery post. A good ground connection should show no voltage drop while the sensor is on so no voltage should be seen.