steveltx

Hello,

This is a 1999 Boxster. I noticed that one wire on the wiring harness of the engine side o2 sensor is

broken.

I tried to find the wiring harness from the web and couldn't find anything.

The wiring harness has the number 1-965 261-1 on it.

It has 4 wires which are connected to the engine.

The other side of the harness is connected to the o2 sensor connector.

Is there anyway to repair the harness? Can I splice the wires and connect all 4 wires

directly bypassing the connector?

Thanks.

Steve

Hi, I replaced mine a couple of years ago, its not too difficult. You need to establish whether or not yours has the e gas throttle. I seem to remember that there is a plastic link on the pedal which a ball joint at one end which can become dislodge, this happened on mine so worth having a look first. Its also possible the hinge has broken, I did a temporary repair on mine using a small door hinge. Definitely a DIY job, hope you manage to sort it soon.

Hi,

Thanks for the reply. I got an used gas pedal (part number 98642302708) from Ebay. At the front of the pedal, there is a cruise control module (part number 99661702103) connected to it. BTW, this is a Tiptronic. I think they just give it to me as a bonus. At the back of the pedal, there is a long steel cable.

Is this the throttle cable?

I want to replace the whole brake pedal as a unit and not to fix the old one. Is it easier that I use the old throttle cable and connect to the new pedal?

Or should I use the throttle cable came with the new pedal and replace the old cable that's connected to the throttle body?

Which way is easier?

For the cruise control module, should I replace my working old one with the new one?

This task doesn't look like straight forward.

I appreciate your input.

Thanks.

Steve

Where is it binding up? Before spending money on a pedal assembly, ensure you figure out what exactly the problem is.

First place I'd check is at the throttle body. Make sure the cable didn't slip off to the side there. If so, the butterfly valve won't open when you press the throttle pedal.

Hi,

It's stuck at the pedal. The pedal is not even in straight forward position. The pedal doesn't move at all. If I push really hard to force it, I still can accelerate the engine.

This is bizarre.

Hi all,

Never thought this is happening. The accelerator (gas) pedal for my 1999 Boxster is not working.

It's stuck when I tried to push the pedal by foot and the engine is not going anywhere.

The part for the whole pedal assembly is very expensive, over $400, This is the Tiptronic version.

I found a used part for about $59.

Does anyone ever had this happening before? Is it a DIY job?

Anything I need to pay attention if I decide to replace myself?

Thanks.

Steve

Hi,

I am suspecting the cracked oil filler tube. AOS was also replaced recently.

I searched the internet a little bit. Many people had broken oil filler tube and

was having the rough idle problem especially for older Boxster.

They also said that if you had a bad AOS earlier, the tube is very likely broken.

Anybody knows how how to hard it is to replace the cracked oil filler tube?

Thanks.

Steve

Hi,

There was no code at all. The battery is very new. I think the electrical condition is good.

Alternator is good.

Is it possible that fuel injection was causing the problem?

Also is there any better way to check the vacuum leak?

Thanks.

Steve

Hi,

It's been a few months since I posted the problem on this thread.

I have replaced the fuel pump, cleaned the idle control valve and the throttle body.

I have also replaced the MAF and even the crank position sensor.

The problem still remains. My mechanic tried to help out but he couldn't find the problem.

I am running out of idea and need to stop replacing parts. It's expensive.

Does anyone have the idea that what I should check next? Thanks so much.

Steve

Hi all,

This is a 1999 Boxster. The car always starts with no problem. Driving high speed is OK.

The problem happened when driving low speed such as stopped at the stop sign, the engine then stopped.

After that it's very difficult to start again and I need to wait for a day and the car will start again with no problem.

I have replaced the crank position sensor and the problem still persists.

I am starting to suspect it's the fuel pump or fuel pump relay. But the car always starts with no problem which puzzles me.

Also there was no check engine light, no OPB code.

The next area I suspect is the throttle body. May be it's too dirty and needs to be cleaned.

Any suggestion is appreciated.

Steve

Steve:

I don't have photos of the Tiptronic transmission housing, so I'm not familiar with the shape.

Although the housing of the Tiptronic transmission is shaped differently from that of the manual transmission housing, there are two points to keep in mind:

1. The bolt pattern is the same, so you can follow the location of the bolts in the photos above, and;

2. On the manual transmission Boxsters, the crankshaft position sensor is actually mounted on the engine case (i.e., NOT on the transmission housing), so it should be in the same location pointed out in the photos.

Maybe someone else can provide a photo of that area with a Tiptronic.

In the photo that you have provided, you can clearly see the lower of the two bolts to which I referred (and it looks like someone replaced the factory OEM hose clamp oat the base of the AOS bellows with a worm clamp). Take a look (or feel) below and very slightly to the rear of that AOS housing lower bolt.

Regards, Maurice.

Hi Maurice,

I finally found the CPS. It's about 1 inch from the of AOS lower mounting bolt. I used my hand to slide down from the

bolt and finally touched the CPS. I couldn't see it but I knew that's the one because I could feel the shape.

The problem now is how to replace it. The location is very deep and the space is very tight. I couldn't even see the sensor.

I think I will need to use my hand to feel the bolt and remove it. This won't be easy.

May be I need to have the garage do it.

Thanks.

Steve

Steve:

You are correct, it is not far from the LOWER of the TWO AOS mounting bolts.

If you put your finger on the lower of the two mounting bolts from the AOS, then go straight down about 4 inches, and about 1 or 2 inches towards the rear you will have your finger on the CPS. IIRC, the one bolt that holds the CPS in place is near the top of the CPS.

Here is another photo that should nail it down for you, although the engine and transmission are really dirty:

To help orient you, the yellow arrow points to the LOWER bolt at the bottom of the AOS housing;

the green circle is surrounding where the inboard end of the psgr side half-shaft (axle) attaches to the output flange of the transaxle (the half-shaft has been removed in this photo);

the red arrow is pointing to the bolt head that would be in the threaded hole that is immediately above the yellow arrow in the PREVIOUS photo;

and the blue arrow points to the CPS. If you click on the photo, you might even be able to see the bolt that holds the CPS in place, although it is covered in dirt in this photo.

If you still are not able to see it, put your finger on the flat little square surface on the transmission flywheel housing to which the white arrow is pointing and then slide your finger to the right (i.e., towards the front), and your finger will be on the CPS.

Regards, Maurice.

Hi,

Mine is Tiptronic transmission. Is the picture different from manual transmission?

There is not much room under the AOS mounting bolt.

Thanks.

Steve

Steve:

The flywheel housing is the part of the transmission case that extends forward (in the case of a Boxster) of the actual transmission and covers the flywheel, clutch and pressure plate, etc... As such, it's not on the left or right side of the car, but rather sits in the middle of the engine bay. At the forward end of the transmission (again, in a Boxster), the flywheel housing mates up to the rear of the engine and, around its circumference, you can see the heads of a number of bolts that hold it snug to the rear of the engine. It is below the bottom of the AOS.

Here is a photo of an engine removed from the car. To help orient you, the AOS is circled in red, the AOS bellows has a blue arrow, and the yellow arrow points to the crankshaft position sensor.

Since the transmission is not mated up to this engine in this photo, you won't see the rear face of the engine. However, if you look for the bolt heads I mentioned earlier, you can locate the CPS in between two of those bolt heads. You can clearly see the threaded holes for those two bolt heads immediately above and below the CPS (click on the photo to enlarge). In your case, those two holes will have the bolts in them as the transmission is still bolted in place.

Regards, Maurice.

Hi Maurice,

Thanks for the detailed information. I know roughly where the sensor is now. I am still trying to find it because there

are just many pipes and steel bars in the area and I couldn't get a clear view.

I have been under the car for 2 days now and still trying. Access to the bolt of AOS was not too difficult from the bottom and I

used it as the reference point, I think it's not very far from the AOS mounting bolt?

I am a little bit frustrated. I am not handy to fix cars. Any suggestion is appreciated.

Thanks so much.

Steve

Hi all,

I searched the net and found a few threads that describe the location of the crank position sensor, one of

the thread even had the picture to show. I was under the car for quite a while and still couldn't match the

picture with the car.

The thread says it's close to the flywheel housing. Where is flywheel housing?

Is it on the driver side or passenger side?

Is it close to the bottom of Air Oil Separator?

Thanks for your helps.

Steve

Hi all,

I want to replace the starter on my 1999 Boxster. Is this a DIY job?

Do we have the DIY instructions posted somewhere in our forum?

How long will this task take and what should I pay attention to?

I already got the Bosch starter and I plan to install it this long weekend.

Any information is appreciated.

Steve

Hi all,

Yes. Finally, I have fixed the P1126 problem. It's the bad Air Oil Separator (AOS).

The problem is not MAF. It's not Oil filler tube. There was no broken vacuum hose anywhere.

One most important thing to check is to check the J tube connected to the throttle body.

This is the easiest thing to check instead of spending a lot of money on other unnecessary repairs.

If you see oil in the connector, then the AOS is bad. The method of trying to remove the oil stick

while the engine is running didn't work.

It took me 5 hours to replace the AOS. The trick for the replacement is simply cut the AOS bellows from below and

remove the clamp from the top. Then install the screw type clamp.

Thanks for all the helps.

Steve

Glad you found the problem and got it fixed.

Just to clarify, you can test the AOS by removing the oil fill cap while the engine is running, not the dipstick.

I figured that I owe you guys an update for the problem since you have been so helpful to me.

No, the problem was not fixed, the problem returned after running for more than 300 miles. It's not the AOS.

I guess that my original AOS is good.

After struggling for a while, I started to check all the hoses around the engine. There are two big tubes on the driver side

on top of the engine that connect the intake manifold and the throttle body via the third connecting piece.

There were adjustable clamps that tighten the tubes and the clamps were not tighten enough which caused the vacuum leaks.

The problem was caused by the garage after they replaced two emission parts and they did a sloppy job putting back everything

back together. This is a BBB recommended garage and that's why I never trust the garage. When I mentioned the problem to

them, they wanted to charge me more to replace more parts. I could waste thousand of dollars more if I believe them.

After I tighten two clamps on top of the engines, the car ran more than 1000 miles so far and there was no P1126 any more.

It's that garage that caused the problem and wasted me hundreds dollars replacing AOS and MAF. The parts are probably all good.

Just to share this with you for this. Thanks.

Steve

I know that I need patience but I spent many hours trying to remove the tube and couldn't. There must be a better way.

I saw a special tool on the internet. It's called ajustable hose remover. It's used to remove big hose simliar to the tube.

It also has a handle that you can pull to remove the tube. Has anybody tried this?

Thanks.

Hi,

I just fixed the P0410 code. I replaced the air change over valve and the electric change over valve.

Both are under the intake manifold.

Hi,

I am having problem disconnecting the air inlet tube from the throttle body. This is the tube connecting

the air filter and the throttle body. This is a 1999 Boxster.

It's a simple connection that the tube is connected to the throttle body by the adjustable clamp. I loosen the clamp but I just couldn't remove the tube from the throttle body. It's a big and wide tube.

Does anyone know if there is any tool that I can use to remove the tube? This is my first step to remove

the throttle body for cleaning. If I can't do this, I might as well forget about the whole thing.

Thanks for your helps.

Hi,

Thanks for the quick reply.

Found the problem. It was the brake pedal switch (The one just above the brake pedal).

I had a problem of not being able to shift the gear when the car is at "P" position.

So I bought a cheap (not OEM) brake pedal switch and installed it. The brand is called Facet and it does fix the shifting problem but after I installed

it, the cruise control stopped working.

Today, I installed my old part back and it wouldn't shift again as I expected but guess what the cruise control is working again.

So the problem is definitely the faulty brake pedal switch.

It's very interesting that brake pedal switch also controls the cruise control.

Steve

Hi.

The cruise control on my 99 Boxster is not working. The cruise control indicator light on the dash will turn on when I park the car and

will stay on as long as the gear is in parking "P" position. It will also stay on when I back up the car (gear in "R" position).

When I shift the gear to "D" and start to drive, the cruise control indicator on the dash will turn off right away.

Where should I start to look for the problem? Does the car has cruise control module somewhere?

Thanks.

Steve

Hi,

I meant the oil filler cap not the stick. Sorry typo. It's very interesting that I could easily remove the cap when the engine was running even

when the AOS was bad. I am 100 percent sure that AOS was bad because a lot of oil was detected in the J tube connected to the throttle body.

Can anybody explain this?

My Boxster is still running excellent with NO P1126 and NO CEL after 200 miles. It used to happen every 50 miles. Very consistent.

It's completely fixed. Thanks.

Steve

Hi all,

Yes. Finally, I have fixed the P1126 problem. It's the bad Air Oil Separator (AOS).

The problem is not MAF. It's not Oil filler tube. There was no broken vacuum hose anywhere.

One most important thing to check is to check the J tube connected to the throttle body.

This is the easiest thing to check instead of spending a lot of money on other unnecessary repairs.

If you see oil in the connector, then the AOS is bad. The method of trying to remove the oil stick

while the engine is running didn't work.

It took me 5 hours to replace the AOS. The trick for the replacement is simply cut the AOS bellows from below and

remove the clamp from the top. Then install the screw type clamp.

Thanks for all the helps.

Steve

Yup cut the old bellows + 11mm socket is a great OEM clamp holder,,,

Thanks for the info. Extremely helpful. I cut the bellows, removed the AOS from the top and then also removed the clamp from the top.

It worked very well. I successfully installed the new AOS. At the bottom of the AOS, I installed an adjustable clamp.

Steve

Hi,

P1126 is the only code on my 1999 Boxster. After I cleared the code, the same code always came back after driving around 50 miles.

Replaced MAF, air filter and even the O2 sensor, still didn't help.

I checked the hose at the bottom of the air oil separator and it seems is OK.

I ran out of idea. May be vacum leak somewhere? Anything else I should check?

Thanks.

Steve

It's too bad that you spent money needlessly replacing the items you replaced but they are the things that are commonly recommended to replace when emission codes come up. Have you done a search on this site by entering the code because I believe you will find a lot of information regarding what this code indicates? My recommendation is that you take the car to a mechanic who understands the Porsche diagnostic tree and has the equipment to track down the problem otherwise you will continue to "shotgun" replace parts that may not need to be replaced. I'm speaking from the experience of also needlessly spending money on parts replacement involving this code and others like it. After spending $700 the problem turned out to be a disconnected twenty five cent vacuum hose so please save yourself some grief and money and let someone who knows what they are doing fix it.

I removed the J tube connecting the oil separator to the throttle body and I found small build up of oil. The oil separator is probably bad because oil

shouldn't get into the throttle body and into the combustion chamber.

I apprecite it so much if anyone can confirm this. Thanks.

Steve

Hi,

P1126 is the only code on my 1999 Boxster. After I cleared the code, the same code always came back after driving around 50 miles.

Replaced MAF, air filter and even the O2 sensor, still didn't help.

I checked the hose at the bottom of the air oil separator and it seems is OK.

I ran out of idea. May be vacum leak somewhere? Anything else I should check?

Thanks.

Steve

Have you tested your AOS? While the car is running and warmed-up remove the oil fill cap... Is the cap difficult to remove? Does the idle drop and motor almost die? If so, the AOS is bad. Also look at your gas cap seal, does it have cracks like the one in this picture?

Hi,

Just checked the oil fill cap. It's easy to remove when the car was running and warmed-up. When it's removed, the idle didn't drop and the motor was running fine.

The gas cap was replaced not long ago and it's in good condition.

What else should I check? Thanks.

Steve

Well, I ordered a new AOS for my 99 boxster on wed, received it today and decided to take a look to see how bad it really is. I will say that it took me at max 15 minutes to remove the old one and replace it with the new one. I didn't need a jack either.

I think I will have a great time with this car. Who would be interested in an aftermarket AOS if it was the same price, but was easily serviceable. I have a couple ideas that I will be playing with to see what I can do.

Hi,

I am thinking about replacing the AOS myself. I checked the bottom of AOS. The two bolts are not too difficult to remove but

the two clamps that attach the AOS bellow to engine seems are very difficult to reach and remove especially when you

don't jack up the car high enough.

How did you do it? Any tip to share? Thanks.

Steve