CEL codes

I just recently had my codes read at auto zone and came up with these 3: 1131, 1537 and 1538. the van is a 96. the guy at the store said the 1131 was from the o2 sensor and said it needed replaced. the other 2 he
didnt seem to have a warm and fuzzy feeling about and said they could be caused from the o2 sensor as well. So before I throw money out over something I know nothing about where should I start to fix this? change the o2 sensor first or something else? any help is appreciated, thanks.

The P1537 is for Intake Manifold Runner Control stuck open bank 1. P1538 is for bank 2 stuck open. These can cause the P1131 code. These controls sticking open will cause the engine to run lean and cause the O2 not to switch properly. Good luck.

The 1131 code "Lack of Upstream Heated Oxygen Sensor......switch, Indicates Lean Bank #1"

Many oxygen sensors are replaced that are good....and problem not solved. There are a LOT of codes for various failures of the oxygen sensors.

You have 4 oxygen sensors......one that is before each of your 2 catalytic convertors (upstream) that are used for air fuel mixture. Then there is one after each catalytic convertor....(downstream) that are used to monitor "catylist efficiency".

As you have BOTH IMRC banks staying OPEN, I would look for a vaccum line being off or other leak.....which could cause the extra air, and the IMRC to not work.

IMRC states.....
They are OPEN when the engine is OFF. (no vaccum)
They CLOSE when the engine is ON....(vaccum)
They will open again when the RPMs are up over 2900rpm. (IMRC solonoid gets signal to block the vaccum)

The indication of a lean condition from one of the oxygen sensors.....and both IMRC banks being open....would lead me to suspect a vaccum leak vs a pinched line.

The IMRC "actuators" are on the passenger side of the engine. There is a RED vaccum line that connects to each one......and an electrical connection to each one. BOTH IMRC actuators share the SAME vaccum source. The IMRC vaccum source is located on the back of the upper intake manifold.....toward the passenger side. It is a solonoid that is mounted on back of the upper intake manifold. There is an electrical connecton on it. The electrical signal closes the solonoid, which blocks the vaccum to the IMRC actuators.

PLEASE NOTE: The IMRC actuators operate with great force.....and the return springs operate with great force.....so keep the fingers clear.

Check to see that the vaccum lines are firmly connected to each actuator, and to the solonoid on the back of the upper intake manifold. Also verify that the vaccum source to the IMRC solonoid is firmly connected.

If they are connected......with the engine running.....remove 1 of the red vaccum lines from one of the IMRC actuators. Feel to see if you can feel a vaccum. If you can.....hold your finger on the end of the vaccum line.....and see if the other actuator pulls the other side closed. If it does.....you may have a leak in the diaphram of the actuator that you have disconnected
.
If you feel very weak vaccum.....then reconnect the vaccum line......and.....I do not remember if you can easily get at the vaccum line on the other actuator....but if you cannot....turn off the engine....remove that vaccum line......restart the engine.....and check that line for vaccum.....and see if you can make the connected actuator close by holding your finger over the vaccum line.

The IMRC actuators are a "dealer only" item.
You might check to see if you can get them online from Millennium Ford in Seattle......they seem to have good prices.

I have some pictures of various projects on my '96 3.8L....including IMRC component locations at
http://community.webshots.com/album/201931518cScpNK

The P1537 is for Intake Manifold Runner Control stuck open bank 1. P1538 is for bank 2 stuck open. These can cause the P1131 code. These controls sticking open will cause the engine to run lean and cause the O2 not to switch properly. Good luck.

Hi Way2old,

I am curious as to why you suggest that the IMRC's being stuck open would cause a lean condition. The IMRC routes the intake air through a different path but does not allow more air into the chambers or allow any air to bypass the MAF.

As you have BOTH IMRC banks staying OPEN, I would look for a vaccum line being off or other leak.....which could cause the extra air, and the IMRC to not work.

The above was stated by wiswind after my post. Just a hunch at first, but I think wiswind verifies my hunch. Vacuum leak will cause vehicle to run lean.

I will also add....that the same would be true if you have a serious leak in one of the IMRC actuators...... But they are kind of pricey......so you would want to eliminate a cheap....reconnect of a vaccum line.....if that is the issue.

I agree that a vacuum leak would cause a lean condition. I was under the impression when I read your post that you were suggesting that simply the IMRC sticking would cause lean. I see now that you meant that a vacuum leak causing the IMRC to stick would cause lean and I agree 100%.

As I stated in a previous post to someone else, We have 1 windstar in our fleet and we hardly ever see it. All I know about the windstar is what I have read here and the shop manual. I was mainly adderssing his O2 code. Too many people will swap an O2 just for staying rich or lean without checking as to why. Thanks for keeping me honest. We deal mainly in Crown Vics and they don't have the stuff on them that the other models do. Thanks again for the question. It made me read closer and I learned something also.