BaysideC4

I recently installed a light bulb in the Check Engine socket of my gauge. It originally read 1500, which means everything is ok.

My check engine light went on a few times while driving recently. It always goes out after a minute or so. I checked the fault code and got a 1224 witch means “Intermittent Oxygen Sensor Failure”.

My understanding is that many things can cause this but I looked under my car and saw that the Oxygen sensor wire is frayed as it leaves the Catalytic converter.

Has anyone experienced this? And how difficult is it to change the sensor?

It seems that removing the wheel makes it easy to get to the sensor but I’m not sure where the other end goes.

Any advice or past experience stories would be greatly appreciated.

Brad

scotsman60

Brad,

The lead from the O2 sensor goes into the engine bay and connects into the wiring loom just below/behind the blower that is mounted on upper left side of you rengine (standing at the back of the car looking forward at the engine).

Its probably possible to get to this from under the car but it only takes a couple fo minutes to take the blower out and everything is in easy reach.

If you replace the O2 sensor with a generic item you'll have use the existing connector and solder it to the leads on the generic sensor (at least that's what I had to do because the connector was different)

The leads on O2 sensor end are moulded into the sensor so I donlt think they can be replaced.

Some people have reported difficulty removing the sensor - I didn't have that problem when replacing mine.

Keep the new O2 sensor clean - silicon apparently destroys them.......

Doug

bj

Brad

Where is the check engine bulb socket and how does one get it to produce the codes?

Thank you
Bill
90C2

horst

Don't buy the generic O2 sensor. You will have problems. Get real thing, don't skimp. The original will deal with moisture properly, the generic won't. I believe about $70.00 or thereabouts. Roy Rogers will sell for a better price than the Dealer.

BaysideC4

bj,

It seems that most cars starting with model year 1991 have the ability to check the DME fault codes with the Check Engine light. 964's before that date will not have a bulb in the socket at all. I read a post by Adrian that said some 1990 cars did have the technology (mostly California models), but the light bulb may not be installed.

I have a 1990 C4 and it was NOT made for California. I figured what the hell, let me throw a bulb in and see what happens. Well, it worked! Another person with a 1990 C4 on this forum had the same success.

Check the link below. Bill Wagner’s site has great detail on this topic. He has done a wonderful job.

<a href="http://members.rennlist.com/billwagner/" target="_blank">http://members.rennlist.com/billwagner/</a>

Hope this answers your question.

Brad

BaysideC4

horst-90C4,

I will go to my dealer and get the correct part, but I guess there is no way of knowing if it will fix the problem until I do it.

Has anyone had other problems that triggered this warning?

Fred, Long Island

Remove the wheel and shields, let the engine run a few minutes to get the unit hot, have the proper wrench that won't slip and have at it. There's a special slip over box wrench made for this...looks like a large flare wrench used on brake hoses. A proper box wrench is best once you've snipped the wires to fit it over.
Use a graphite type lubricant on the threads. The new Bosch units come with a dab of the stuff on them. Careful of crossthreading as you reinstall!
The wire feeds through the sheetmetal pretty easily. The plug in the engine compartment is in a vertical position clipped to the frame. It has ribs on each end that line up when plugged together. That lets you do it more by feel than sight as it is tucked behind the blower.

scotsman60

I've heard about the reported problems with moisture and the generic unit however I can say that I've never had any problems with mine.

Of course I live in Southern California where there isn't exactly a lot of moisture.

Doug

horst

If you have a spare couple of minutes, why not take the large air tube out, and take out the blower motor- 2 10mm bolts. Gives you all the room in the world to see the plug for the O2 sensor, and while you are there, check the resistor on the air tube to make sure it is the latest one, clean stuff, etc. If the original O2 sensor has lived ther a long time- it could be a bear to remove. I have never had to use heat, but mabey you might- also consider putting some high-quality penetrating oil on it and let that sit overnight.

horst

Oh- I am the guy with the 90C4 that got the check engine light to function. BUT: I got the free Porsche depot-level upgrade of my DME, and my car is California spec. I think it was one of those 2 factors, mabey both that got it to work. I think Jeff Curtis' car is a 92, and when he dropped by some time back, we tried it on his car and that did NOT work.

BaysideC4

Interesting, I am the third owner so I can't say what’s been upgraded. All I know is that it works and my car is a C02 (not California).

Seems to be a huge difference in price between the generic and the OEM 02 Sensor. I noticed that the OEM part has a rubber ring in the middle of the wire. Does anyone know what that is?

horst

That's the grommet to seal where it passes through the engine tin.