OK, so I bought the Equus 3100 code reader to investigate the check engine light that appeared last week. Expecting to see the dreaded Secondary Air Injection message, I was surprised to see code P0341 show up. The manual describes this as "Camshaft Position Sensor Circuit Range/Performance". WTF does that mean?

Anybody have any ideas of what this means or how to keep it from recurring?

I did have the RS flywheel and clutch installed over a month ago, but I wouldn't think there would be any correlation.

One more question: What is the correct procedure for a "trip drive cycle"? Just taking the car out for a drive or is it a certain procedure i.e. specific time at certain revs/gears?

Thanks for your help. Subscribing to this board is money well spent!

Dave

 

Limited info, but since you haven't had any other replies:

Not exactly sure, since my experience with camshaft position sensors failing is not on my p-car, but it likely means the cam position sensor needs to be replaced.

You didn't say if your car runs ok or not, but I'm assuming it's currently running. In that case the cam position sensor is not completely dead. When they go completely, the car's computer can't keep accurate timing, and the engine usually doesn't run.

Best bet is to have the car checked out by your mechanic. FWIW, problems with the CPS aren't something I've seen on Rennlist before (not that I'm an old-timer here either).

You're right, the flywheel/clutch replacement should be unrelated, unless the CPS was crunched or something during the process.

Drive cycle info is in the archives. It's a lengthy process, and I don't remember it all offhand.



-Chris

 

Chris,
Thanks for the reply. I didn't even know there is a camshaft position sensor. I will have my mechanic check it out. Did a search for drive cycle and came up with the list. Sounds bizarre, but I will give it a shot.

Thanks,

Dave

 

The CMP on 993 models is in the ignition distributor. The reality is that without the Bosch KTS300 (Hammer) or PST2 that code means nothing.
There may be a fault, but I would want to to replicate the problem and check all the other systems before changing parts. Clear the code and drive the vehicle again, see if the code re-appears.

 

GMS,
Hate to sound stupid, but what is the CMP? You mention it is in the ignition distributor.... I did have the distributor belt changed as well as new cap and rotors when the engine was out. Could this be related?

The car is running great.

Thanks,

Dave

 

The CMP (camshaft position sensor) is not in sync with the CKP (crankshaft position sensor). These two need to be in sync for the firing of cylinder 1. If they are off, there can be fuel injection and knock sensing issues. I would recheck the work that was done so this may be the cause of you issues. Check the belt, the caps, and that the rotors are on correctly. If this is not it, there are a series of things to check, and you won't like anyone of them.

 

You did not mention how many miles are on your car, but its very possible that the twin-distributor drive belt has snapped and this should be checked out immediately.

Pull the caps and see if you can rotate the lower rotor by hand, if so, you need to have that repaired ASAP.

Porsche sells a rebuilt (just a new belt) distributor for $ 800. FWIW, we can replace the belt in your distributor for $ 170, complete.

 

There have been problems on the 964, where this TYPE of code has occurred,
because of a problem in the ignition wires/connectors. Obviously, check the
connections from the sensor to the DME (pins 53 & 21), but also check all the
engine grounds.

It does seem strange that this problem occurred shortly after a clutch job.

Good Luck
Loren
'88 3.2

 

Reviving an old thread here - and should be an easy question for those of you that have worked on your distributors.

Yesterday while stuck in road construction on a 95 degree day, right about the time my oil temp gauge went above the 9:00 position, my car threw a P0341 code.

I have no record of distributor belt servicing in my car's 126k mi life (on my list along when wires/plugs are due in 6k miles) . So, I followed Steve's advise above and tried to spin the lower distributor rotor. I cannot spin it, however, it does "wiggle" a little. Maybe an 1/8" of a inch to the right. Is this wiggle normal or should the rotor be completely locked in place?

Thanks,
Matt

 

I also have a small amount of wiggle, maybe an 1/8" as you measured.
It was definitely not locked in place. So you aren't alone. No codes though...

 

Good to hear.

I've cleared the code and been out just enough to get the car up to temperature twice now. It has not thrown the code again. I cannot detect any other symptoms, but I'm a rookie here.

For the time being, I'll chalk it up to caps/rotors/plugs/wires all nearing the end of their service life. Let's hope it doesn't come back until closer to winter when I had planned the major ignition system maintenance anyway.

 

Was even hotter today - 99 degrees. Immediately noticed the car is running too hot. Sure enough, dead oil fan resistor verified by connecting the 3 and 7 pins of the fan relay. New resistor is on order from Sunset. Also forced the fan to high speed at all times in the interim. I had just checked the resistor back in October... guess it died during the winter.

Good news is that the P0341 has not returned. Fingers crossed it was a random issue that may or may not have been caused by excessive heat.

 

Sadly the P0341 is back. After I clear it, it will come on within 30 miles or so.

I'm trying to avoid the "shotgun" troubleshooting approach and willing to invest in some time to get to the bottom of this.

I presume I need to get more data, so that means a PST2, Hammer, or UDT999/PDT999. I'm leaning strongly toward the UDT999. Does this seem like a reasonable next step? What data should I be looking for?

PS. At this point, I'm ruling out the durametric, because it doesn't support the ABD bleed procedure that I'll need every year or so. (lucky me, my car as the ABD).

 

I agree with the sentiment that more information is better.
In this case, however, I'm not convinced that a scan type of tool will help you.
Search the digital version of the 993 workshop manual for "hall sender".
The workshop manual lists an oscilloscope as the tool to verify that it is operating properly.
You might want to check on the price of a new hall sender.
I have a receipt somewhere that shows my hall sender (sensor) was replaced at some point, prior to my ownership.
Sometimes a code will point right to the problem, sometimes it is a reflection of a different problem.
Knowing other engine data may help. Hard to say for sure... The engine might be running poorly because of the (possible) hall sender issue and the data that the tools can gather may not help you because everything is off because of the (again possible) hall sender issue.

Hey, trying to help you think through this. Keep us posted.

 

Appreciate the perspective. I saw the mention of using the oscilloscope in the workshop manual. Before I pull the trigger on this (learning that oscilloscopes are not cheap)... would love someone to help me better understand the high-level troubleshooting steps here. I've never used an oscilloscope, but do have basic engineering background (audio and software).

My guess is that I need to tap into the DME (still unsure how to do this) and measure a voltage change over time using the oscope.

I'm assuming:

1) the MIL is triggered by x sensor sending/not sending y value over z threshold n number of times
2) The real code reader (Hammer, PST2, etc) can confirm x. My crappy code reader is just showing generic trouble code. Unsure if I should consider this confirmation that x = hall sensor.
3) The oscilloscope can confirm y (voltage over time). Assuming there is a voltage peak every time the distributor completes a revolution
4) z and n are unknown and programmed into the DME (can't seem to find in the WSM)

So, to confirm the hall sensor fault and not some other ignition problem, I need to confirm x, and measure y, hoping to see y hit/miss some unknown exceptional value under some unknown intermittent condition. Ugh. Please tell me there's a better way ;-)