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2002 C2, 95k miles, original exhaust and O2 sensors.
A few months back the CEL went on, Durametric says P0420: Porsche fault code 40 - Cat. conv. efficiency bank 1. CEL has stayed on so I investigated further. Pre- and post-cat O2 sensor voltages shown in attached charts, upper chart for Bank 1 and the lower for Bank 2. Warmed up the system at idle, then throttled up to 2.5 - 3k three times, two short, one long, during which time all sensors went near zero.
It looks like Bank 1 (upper chart) post-cat sensor is showing a problem while Bank 2 (lower) looks fine. (I started capturing Bank 2 after Bank 1) Also for a few years there has been a little rattling on the driver's side exhaust which I've suspected is a failing cat, but the exhaust system has not been recording any faults until now.
After having read a few related threads, it seems fairly certain that the Bank 1 cat is failing, perhaps with a loose element that reduced cat performance after the third throttle bump in the charts below. I'm leaning that way because it appears the sensors are all reporting data at about the same rate, oscillating when expected, except for post-cat Bank 1's sensor which begins the capture looking like it is largely reporting correctly but ends with oscillations that shouldn't be there.
There has been no perceptible change in performance, and I have over a year until the next smog inspection, so there's time.
Does this information indicate a pretty strong likelihood of a failing Bank 1 cat? Or are there additional diagnostic steps I should take to eliminate other causes?
My 1999 911 Carrera started smoking at a streetlight. Very smelly blue smoke was coming from under the engine cover. I pulled over and popped the cover. Blue smoke was coming from somewhere under the engine (not the exhaust). The engine stopped very suddenly.
We don't have a local Porsche dealer, but the Subaru dealer owns a bunch of 911s and he has a couple Porsche mechanics. I had it towed there.
The C1 fuse ("Engine Electronics") was blown. They replaced it, but as soon as they turned the key, the "cam adjuster wiring harness" (I do not know what this is) began to smoke, and the fuse blew again.
They disconnected the cam adjuster wiring harness (I don't know what this means, and neither did the service advisor), and the fuse stayed intact, and they got the car started. They were able to drive it out to the parking lot with no problems.
They said I need a new cam adjuster wiring harness (again, no idea what this is), and this would require an engine out repair, which they could not do. They estimated this work at $5,000 to $6,000.
Additionally, they did not know how drivable the car was with a disconnected cam adjuster wiring harness.
So ... how bad is this? (Service report image attached.)
To all 996 owners with PSE, especially those with a 4S.
I think my 996 C4S exhaust behaves oddly. I think it's a fault but you might tell me it's normal behaviour. The problem is that I've always had this 'fault' on my car so I don't know if it's a fault or intentional behaviour. If you have the same car, perhaps you can shed some light on this.
When I start it, it's noisy and sounds great. It quiets down as it runs for the first 5 mins.
I have the PSE system and when I press the button you can audibly hear the exhaust note change - quieter when on and louder when off. Default is off so loud.
Here's the rub. Up to around 1500rpm it's got a good noise then it fades out to the point where it's so quiet it's like driving my partners Yaris. If I keep accelerating, when I get to around 3500rpm the exhaust suddenly gets loud again. I mean it's immediate - like someones flipping a switched marked loud. It sounds great.
It happens in 2nd and 3rd gears most noticeably and the PSE is in the 'off' position. If I have the PSE button on, then it's just quiet all the time and that works fine.
So why the silent spot?
I did read somewhere that German market cars might have had a system that turns on and off the PSE at certain speeds to prevent people driving round residential streets with a loud exhaust but information is thin and I don't think I was ever on UK cars.
I have also had a small go at checking vacuum pressure at idle on both sides of the Y piece in the engine bay but both hold good pressure. One side has only a microscopic leak but not enough to cause this kind of issue.
Hi everyone, I just got a set of gauges for a 2005 996. I'm building a simulator for PC and would like to wire the gauges to work with racing games. I am in need of the wiring diagrams for the cluster. If anyone has a picture or manual that can help me out it would be great! Looking for inputs, power, signal.