P1072 OBD code

[JHZR2]

My mother's 97 Plymouth breeze has been a pretty good car. Pretty solid, other than a spot of rust on the underside of the hood and some rear bushings, it has no issues - even has original battery!

Today we encountered a CEL. It was P1072.

My issue is that I'm seeing mixed stuff on it. Seems like 1072 often occurs with 1075 - not the case here.

I see mixed stuff - MAF, fuel pressure, maybe O2. Very unclear. Can anyone help shed light on P1072? Often google confuses P0172 for this.

Thanks!

 

[NHGUY]

http://www.allpar.com/forums/index.php/topic/90940-code-52-help/

 

[Trav]

Codes like this are nasty because it basically says the ECM detects an issue but doesn't know where the source of the issues are coming from, it doesn't see a true hard part failure.

Check for a small vacuum leak. How does it run otherwise?
A very small leak between the front and rear O2 can also throw a code like this by driving it rich by the small leak creating rapid voltage fluctuation in the rear O2.
It totally confuses the ECM as it already sees a rich condition from the front O2.
Wild swings on short term fuel trim are a good indicator.

MAF and fuel pressure issues usually effect starting and drivability.
Being OBD II a scan tool would be more than helpful but if you have a vacuum gauge look for a slight reduction of vacuum. Pull a plug and see if its running rich.

 

[JHZR2]

Car starts and runs perfect. MPGs on par with historic levels.

So it really is a doozy.

 

[Warstud]

Originally Posted By: JHZR2
Car starts and runs perfect. MPGs on par with historic levels.


I'd just clean the MAF and call it good....until you start to experience some type of symptoms.

 

[Trav]

It could be but who knows it could be something simple.
Quote:
Car starts and runs perfect. MPGs on par with historic levels.


Although this doesn't totally eliminate the MAF and fuel system it looks a lot less likely there is a fault in these areas.

 

[yonyon]

I've never heard of that one. Is there any chance the tool used gitched on you and it's really a P0072 code? It would be a single bit error and P0072 is pretty common and all... Have you confirmed a correct read using a different tool?

 

[Trav]

I think this is similar to Nissans P2a00 and P2a03 codes. It does seem to be recognized code.

 

[Merkava_4]

Originally Posted By: Warstud

I'd just clean the MAF and call it good....until you start to experience some type of symptoms.


Out here in California, it don't matter how well your engine runs;
if you got a check engine light, you automatically fail smog.

 

[The_Eric]

I didn't think that there was a MAF on this car? Do you mean MAP?

Some data would be helpful.

 

[JHZR2]

Originally Posted By: Merkava_4
Originally Posted By: Warstud

I'd just clean the MAF and call it good....until you start to experience some type of symptoms.


Out here in California, it don't matter how well your engine runs;
if you got a check engine light, you automatically fail smog.


That's the concern here - car is in NJ same rule applies.

Inspection isn't due until October of 13, but we aren't one to drive with a CEL on if it can be avoided. If it is cut and dry, I'd just change the parts. If its a tough one, it may be best to wait, throw the $500 in parts at it after it fails, then move on.

 

[GMBoy]

Since that code indicates a rich condition on bank 1, that rules out vacuum leaks (they cause lean conditions). If it were me, I would suspect the plugs. If one or more are slightly missing they would cause the rich condition. Plus, you can do this easy on that car for not much money so worth the money. Do the wires too. I assume the air filter is clean.

 

[Trav]

Quote:
Since that code indicates a rich condition on bank 1, that rules out vacuum leaks (they cause lean conditions)

True it causes a lean condition but you need to take into account how the ECM handles a perceived lean condition.
Check it yourself with a scan tool, pull a small vacuum hose and watch the STFT add fuel causing it to add fuel.
This does not rule out vacuum leaks or air leaks after the MAF or even an exhaust leak.

AFAIK this model only has one bank, i maybe mistaken but i don't think a V engine was offered in this model.
A small leak between the air cleaner and throttle body could also cause this.

This is not the lean bank 1 code P172 this is P1072.

In cases like this if i find nothing obvious its time to get the 5 gas analyzer, scan tool and vacuum gauge on the job before replacing anything.

 

[JHZR2]

Originally Posted By: Trav

AFAIK this model only has one bank, i maybe mistaken but i don't think a V engine was offered in this model.
A small leak between the air cleaner and throttle body could also cause this.




Its the Chrysler SOHC 2.0L 132hp engine.