I finally pulled the codes.....

IronMonkeyL255 · Post by **IronMonkeyL255** » Tue Nov 16, 2004 5:47 pm

Since I have been having so many problems lately, I went ahead and pulled the codes.

I got:

31 - Throttle Sensor; abnormal voltage input entered from throttle sensor

22 - Knock Sensor; abnormal voltage produced in knock sensor monitor circuit

49 - Air Flow Sensor; use of improper air flow sensor

The 22 could explain why i've been getting such bad gas milage, if it's been retarding the ignition.....

Is this 49 talking about the MAF sensor?

Are all of these replacable/repairable?

What's a good way to check them?

boostjunkie · Post by **boostjunkie** » Tue Nov 16, 2004 5:56 pm

In my experience (and a lot of people on this board know I have mucho experience with these codes) is that when there is a problem with one of the sensors, that ALL of the codes are thrown. My guess is that the ecu is getting an abnormal reading from one sensor and doesn't realize whether the wrong signal is the right one or the right one is the wrong one.

I do know that Josh posted a description on how to check your TPS. Search for Legacy777 and TPS, or something like that. I think it might also be on his website.

The airflow sensor is the MAF. I remember there was a description on how to check the MAF sensor in the Haynes manual for the Legacys. I don't have that manual anymore, but someone one here has to have it.

Finally, have you upgraded your knock sensor to the updated one? It's been so long since I've read about this, but I think the upgraded one has a gray housing. Do a search on upgraded knock sensors just to make sure.

IronMonkeyL255 · Post by **IronMonkeyL255** » Tue Nov 16, 2004 5:57 pm

Also, are the MAF sensors interchangable between the years and n/a and turbo?

I have a (not so) willing test subject in a '94 n/a.....

IronMonkeyL255 · Post by **IronMonkeyL255** » Tue Nov 16, 2004 5:58 pm

I have the Haynes Manual.

I'll have to check that out.

boostjunkie · Post by **boostjunkie** » Tue Nov 16, 2004 6:06 pm

To my knowledge, only the 90-91 n/a 5-spds share the same MAF sensor as the turbos. The easy way to know for sure is to take a look at the housing. If the n/a legacy has the same metal casing, it's the same as the turbos. If it's the black plastic housing, it's not.

IronMonkeyL255 · Post by **IronMonkeyL255** » Tue Nov 16, 2004 6:09 pm

Crap.

I STILL need to find a multi-meter.

IronMonkeyL255 · Post by **IronMonkeyL255** » Tue Nov 16, 2004 6:12 pm

Are they compatible, though?

It's the black plastic housing in the n/a.

Will the n/a one crap its pants when it see how much air is going by?

They both have the same color wires heading into it, which leads me to believe they serve the same purpose.

I noticed the n/a one has an extra pin compared to the turbo one (turbo only has 4 pins with 5 wires).

boostjunkie · Post by **boostjunkie** » Tue Nov 16, 2004 6:17 pm

No, they are not compatible. The ecu won't even be able to understand the sensor signals on the black housing MAF.

IronMonkeyL255 · Post by **IronMonkeyL255** » Tue Nov 16, 2004 6:19 pm

crap.

IronMonkeyL255 · Post by **IronMonkeyL255** » Tue Nov 16, 2004 8:13 pm

Ok.....

I just got a multi-meter and checked my battery and the MAF sensor.

My battery is putting out 11.6v (hasn't been charged lately) and the MAF sensor is seeing the full 11.6.

That's pretty much all I can check without a scan tool.

vrg3 · Post by **vrg3** » Tue Nov 16, 2004 9:12 pm

I'm confused -- do you have the right MAF sensor or not? If you have the black plastic MAF sensor on your car, drive very carefully until you get the right one on!

Do you have the revised knock sensor installed already?

IronMonkeyL255 · Post by **IronMonkeyL255** » Tue Nov 16, 2004 9:38 pm

I have the original, metal MAF sensor on there.

I actually CAN'T drive it right now, as it won't start.

I may just say screw it and swap out the starter and see if that does the trick. It's lifetime replacement, so I can get the new one for free.....

Any way to tell between original and revised knock sensors?

vrg3 · Post by **vrg3** » Tue Nov 16, 2004 9:52 pm

The original sensor design has a gray connector. The redesigned one has a white connector.

Post by **Legacy777** » Wed Nov 17, 2004 3:32 am

I would suggest trying to clear the codes, and then rechecking to see what's in there. The chances of all that stuff being bad is slim. The other alternative is that your ECU may be on the fritz....which would partially explain the car not running.

IronMonkeyL255 · Post by **IronMonkeyL255** » Wed Nov 17, 2004 7:38 am

I was going to get the starter switched out, as I believe that may be on the fritz.

I'll go ahead and clear the codes and see if they come back when I get this running again.

legacycentral bbs

A forum for 89-94 BC-BF(BJ) Legacy Owners and Fans

I finally pulled the codes.....

I finally pulled the codes.....