What is code 51?

[ShadowFromHell]

After 10 min of driving my 89 CSX is throwing code 51. The code list I have in the car says this a issue with the baro reading. But I just searched TM.com and I found a bunch of posts about bad O2 sensors. Which is it, and how do I fix it? I've never had this code before. The baro is hooked up and the vacuum lines were redone a few years back. The car has been in storage for the past 4 years. The code seems to just pop up on the freeway, but I haven't drove it on back roads to much. Remember the 89 CSX uses a SBEC.

Thanks.

[GLHNSLHT2]

There's this site out there that's been there for going on at least 15 years that lists all the codes called minimopar.net. Bookmark it.

[ShadowFromHell]

I think that's where my list was printed from. I'm guessing code 51 changed over the years. Just not sure what to do to correct the problem. Is it possible the baro solenoid is "stuck" and not switching over to atmosphere like it is supposed to? Causing it to read manifold pressure and not atmosphere causing a code? I've bypassed the baro on more then a few cars over the years with no issues. But this is the only turbo sbec car I've owned.

[GLHNSLHT2]

go there, read it, it's not where your list was printed from.

[ShadowFromHell]

Minimopar.net says for 86+ the O2 sensor is reading lean for too long. On TheDodgeGarage.com says for 89-90 VNT, which I have says the baro reading is out of range. That's my confusion. I searched TM.com before I posted this. Found nothing on baro, all about bad O2 sensors. But I am thinking maybe the codes changed.

- - - Updated - - -

My list was printed from TDG.com. Before smart phones I always kept a code list in my cars.

[GLHNSLHT2]

Read the big bold print at the top of the page at TDG.com. Not verified if they're accurate.

[Fox]

check the sbec connection i got the same code when the plug was loose on mine

[ShadowFromHell]

So is the general consensus that TDG is wrong and it is a lean code? My Chrysler cartridge for my OTC 2000 only goes to 88, or I'd hook that up and see what it's doing. I've got a 91 Ford, Chevy, and Chrysler cartridge but I've never used it and don't have the cards for it that tell you what is what.

[GLHNSLHT2]

Plug the 91 cartridge in, the commands and locations are the same for 99% of them.

[ShadowFromHell]

So I should be able to use the "cheat sheet" for the 88 cartridge? I thought about trying to contact OTC but I think that's a waste of time. I hate throwing parts at cars, but I've got the known good O2 sensor from my turbo neon bolted to its new motor on a engine stand in the garage. I am going g to swap it into the CSX tomorrow. The one in the CSX is 8 years old but has maybe 1200 miles on it. But it's a Bosch unit, and I found a old post made by Turbovanman saying he has had a lot of issues with the Bosch units in our cars, primarily premature failure. I've worked on and around fuel tankers for so long that I really don't smell fuel anymore but my wife rode in it tonight and said it smelled bad like it was running rich.

[GLHNSLHT2]

Yes the sheet or book works for locations of data. Should also have a small description of what you're looking at even on the OTC 2000's smaller screen to figure it out. As for bosch O2's I've run them for years on all my turbo cars and haven't had issues with them. From what I've seen they run the car more consistent to Stoich readings (when a wideband is hooked up to monitor them) than the factory NTK O2's do. The NTK's run on the rich side from what I've seen.

[ShadowFromHell]

Put a new O2 in it and all is good. I had the sensor and since I had changed it before I knew it would be easy to swap out.

So I think we can SAFTLEY say code 51 on a 89 csx is a lean code, not a baro code. May be a baro code on 90 vnts. Who knows.

[HSKR]

Bosch sensors are crap. Use NTK or Denso brand.

[ShadowFromHell]

Who knows what this one is. Robbed it from my turbo neon since the engine is out of it lol.

[GLHNSLHT2]

Love my Bosch sensors. Never had one fail. Great for stock, Wideband for anything modded.

[ShadowFromHell]

This one is obviously junk. Has MAYBE 1200 miles on it. Easily 8 years old though. Maybe 10.