Engine Codes for your reading pleasure...

[BigBadWimp]

Hey guys, I was hoping you could help me out with these... I went to Advance Auto Parts to get my codes scanned and it came up with the ones below. The guy there said it could've started with the egr valve and all the other codes might just be related to that one. What do you guys think? Thanks in advance for any help you guys can give me.

KOEO Code 335
EGR PFE/DPFE Volts
Out Of Range

KOEO Code 539
A/C Or Defrost On
During Self-Test

Memory Code 172
HO2S (sensor)
System Lean
(Bank 1)

Memory Code 176
HO2S (sensor)
System Lean
(Bank 2)

Memory Code 181
No Definition
Available

Memory Code 186
No Definition
Available

Memory Code 189
No Definition
Available

Memory Code 211
Profile Ignition
Sensor
Circuit Malfunction

Memory Code 556
Fuel Pump
Primary Circuit
Circuit Malfunction

 

[MrShorty]

SOP for a long list of codes like that is to start with the KOEO codes.
You list two KOEO codes: 335 and 539.
As indicated by your description, most likely the 539 is a result of having the AC switch turned on when you ran the test. Next time, turn the AC off when running the test and the 539 should go away.
The 335 seems pretty common. Note that a KOEO code has to be electrical in nature, so this is almost never a problem with the EGR valve itself. Usually seems to be a fault in the EGR position sensor circuit or the sensor itself. 1st step in diagnosing any code is to check the wiring between the offending sensor and the PCM.

After resolving the KOEO codes, the next step would be to run the KOER test and resolve any codes that come up there before dealing with the memory codes.

And, for those codes that you list "no definition available," try the code list off of www.dalidesign.com/hbook/eectest.html There's also a description of how to perform the EEC-IV self-tests with a jumper wire and a voltmeter, so you don't have to take it back to Autozone to pull the codes as your working on it.

 

[BigBadWimp]

Thanks a ton for the input, Shorty. Btw, I posted this problem on a different forum and never got a response, but here I get one in a matter of minutes, I love this forum! Anyway, can someone guide me on how to check the wiring that Mr.Shorty was talking about? Where is it and am I just checking to see if it's loose?

 

[MrShorty]

A wiring diagram will prove invaluable. Try the wiring diagrams in the vehicle repair guides at www.autozone.com They are often adequate for this sort of thing.
Check for loose/broken connections.
Verify Vref
Verify continuity between the sensor and the PCM.
Then check the sensor itself. These sensors seem to fail fairly frequently, so I wouldn't be at all surprised if you end up buying one.

 

[Runnin'OnEmpty]

The 181 and 189 codes are O2 related (lean), each bank. The 186 is "injector pulsewidth higher or MAF signal voltage lower than expected".

These codes could be caused by a vacuum leak, or a dirty or faulty MAF. How is it running?

 

[BigBadWimp]

It runs somewhat poorly these days, like it's having fuel delivery problems or something. If I let it run for a while, rev it a little, then head off on my day's journey it seems to be fien but it seems to have less power.

 

[Runnin'OnEmpty]

I'll have to second what MrShorty says, and clear the codes one by one, starting with (probably) the EGR position sensor. You may have 2 or possibly 3 different issues.....

 

[BigBadWimp]

Ok, thanks guys.

 

[Brain]

I just wanted to add a little. I went to get emissions testing done on my '91 yesterday (have to get it done to title it), and it failed because of high CO readings. I looked at the poop sheet that lists the polutant levels, and I saw that hydrocarbon (HC) levels and carbon monoxide (CO) levels were high and that nitrous oxides (NOx) levels were really low. There wasn't a code set on the way to the testing station, but there was on the way back home. I pulle dthe codes, and one of them was 172 (one of the same codes you have). There is only one oxygen sensor in the '91 (so I wouldn't get a second code for bank 2), but the system indicates a lean mixture.

So the system thinks it is lean, richens the air/fuel mixture, and ends up failing the test because of a rich "actual" mixture...I guess it makes sense.

BTW, the reason I think the O2 sensor went bad was because of a bad head gasket letting coolant/steam into the exhaust system. Anybody know if that kills a catalytic converter?

 

[Positive Vibes]

Like Runnin'OnEmpty said, it could be a dirty MAF (try a search on MAF cleaning), to a vacuum leak. I would start with the cheap things first. Also PCM or your FPRC, those are cheap and easy to install. I would also buy a Chiltons manual, this will have schematics and diagrams that will help you out a lot.

 

[BigBadWimp]

Well, I cleaned the MAF because of the cheap and easy reasons and it hasn'[t thrown a code since and runs much much better. I might still check out the egr position sensor thing just in case...

 

[Positive Vibes]

Well, I cleaned the MAF because of the cheap and easy reasons and it hasn'[t thrown a code since and runs much much better. I might still check out the egr position sensor thing just in case...

You did have the battery disconnected when you cleaned the MAF, correct? That also clears/resets the computer. Did you notice any difference in the performance of the engine after cleaning the MAF?

 

[V8Exploder]

Is there a way to pull codes w/o a tester ? I had a 93 Taurus SHO and there was a port that if you jumped it with a paper clip, it would flash the Check Engine Light, and how many times it flashed, there was a chart on the net that showed what the code was. I think I am in need of a MAF cleaning and a o2 change and a seafoam treatment. I will have 150k miles on it by the end of the week. When do you need new cats ? I'm thinking of having 2 high flows welded in. Thanks guy !

 

[performancenut]

Try a can of Sea Foam for good measure.

 

[MrShorty]

Is there a way to pull codes w/o a tester ? I had a 93 Taurus SHO and there was a port that if you jumped it with a paper clip, it would flash the Check Engine Light, and how many times it flashed, there was a chart on the net that showed what the code was.

Your '93 Taurus was EEC-IV/OBD-1 which does allow you to run the self-tests with simple tools. Your '96 uses EEC-V/OBD-2, and they don't have such functionality. You'll need some kind of scanner/code reader to get the codes.

 

[V8Exploder]

stupid technology thanks a bunch

 

[BigBadWimp]

You did have the battery disconnected when you cleaned the MAF, correct? That also clears/resets the computer. Did you notice any difference in the performance of the engine after cleaning the MAF?

Yeah, I had it disconnected. The performance is much better! It's so weird to me that doing something so simple can help out that much.