Notices
996 Forum
Sponsored by:
Sponsored by: LN Engineering

P0343, woe is me

 
Old 04-28-2019, 03:22 PM
  #1  
VFRMike
User
Thread Starter
 
Join Date: Dec 2016
Location: San Diego
Posts: 47
Likes: 0
Received 0 Likes on 0 Posts
Default P0343, woe is me

2003 996, 2wd, man trans
here's the run-down, symptoms:
  • when fully warmed-up, driving at 2800-ish RPM at light throttle, there is an intermittent surge or jerk, best described as a 'hiccup' felt
  • very intermittent hard starting (crank, no start) after a short hot soak, starts on 2nd or 3rd try. Has stalled two or three times at idle, soon after coming off of a long freeway run (but not immediately after)
  • has thrown P0343 code a couple of times, after experiencing the 'hiccup' for an extended period (long freeway drive, smooth road), freeze frame data always shows it at 2840RPM
  • one time also recorded misfire codes on the opposite bank at the same time as the P0343
  • check engine light does not stay on
The camshaft position sensor for bank 1 seems pretty well hidden, but at least I could see there were no signs of rodent activity in the engine bay

Last edited by VFRMike; 04-28-2019 at 05:42 PM. Reason: Cleanup
VFRMike is offline  
Old 04-29-2019, 09:58 PM
  #2  
VFRMike
User
Thread Starter
 
Join Date: Dec 2016
Location: San Diego
Posts: 47
Likes: 0
Received 0 Likes on 0 Posts
Default

Any suggestions or anecdotes?
VFRMike is offline  
Old 04-29-2019, 10:06 PM
  #3  
996AE
Addict
Rennlist Member
 
996AE's Avatar
 
Join Date: Jan 2013
Location: SoCal
Posts: 3,391
Likes: 0
Received 2 Likes on 2 Posts
Default

There is a bracket that holds on the sensor that is a known failure point. it can crack and vibrate. Sounds like it with the intermittent failure.

Might want to get cam deviation checked to be sure nothing more going on.

Do you have service history?
996AE is offline  
Old 04-29-2019, 10:23 PM
  #4  
Ahsai
Addict
Rennlist Member
 
Ahsai's Avatar
 
Join Date: May 2005
Posts: 7,281
Received 2 Likes on 2 Posts
Default

P0343 is bank1 cam sensor shorted to B+. The sensor should be below the alternator. Need to check the wiring of the sensor. No way around that.
Ahsai is online now  
Old 04-29-2019, 10:27 PM
  #5  
VFRMike
User
Thread Starter
 
Join Date: Dec 2016
Location: San Diego
Posts: 47
Likes: 0
Received 0 Likes on 0 Posts
Default

So is the sensor located at the "front" of the engine (rear of the vehicle)?
When I try to look it up, I find varying descriptions.
If I'm getting a cam position sensor fault, will my deviation readings be accurate?
VFRMike is offline  
Old 04-29-2019, 11:05 PM
  #6  
Ahsai
Addict
Rennlist Member
 
Ahsai's Avatar
 
Join Date: May 2005
Posts: 7,281
Received 2 Likes on 2 Posts
Default

Yes, it's the black connector to the right of the green cam plug. I think the DME is smart enough to detect a short and ignore the bad readings. Do you have odd cam deviation readings?


Ahsai is online now  
Old 04-29-2019, 11:30 PM
  #7  
VFRMike
User
Thread Starter
 
Join Date: Dec 2016
Location: San Diego
Posts: 47
Likes: 0
Received 0 Likes on 0 Posts
Default

Ahhh, I see it in the picture, thanks.
I haven't checked cam deviations yet, will have to fire up the Durametric this weekend
VFRMike is offline  
Old 04-30-2019, 09:58 AM
  #8  
exthree
User
 
exthree's Avatar
 
Join Date: Dec 2014
Location: Pocono & Marco Island
Posts: 168
Likes: 0
Received 1 Like on 1 Post
Default

The Variocam+ will give a slight, brief "surge" at about 3100 RPM's. /X3
exthree is offline  
Old 04-30-2019, 01:23 PM
  #9  
VFRMike
User
Thread Starter
 
Join Date: Dec 2016
Location: San Diego
Posts: 47
Likes: 0
Received 0 Likes on 0 Posts
Default

This is definitely not a variocam surge, it's just below 3000RPM and harsh
VFRMike is offline  
Old 04-30-2019, 01:44 PM
  #10  
Ahsai
Addict
Rennlist Member
 
Ahsai's Avatar
 
Join Date: May 2005
Posts: 7,281
Received 2 Likes on 2 Posts
Default

I suspect your bank 1 cam sensor is acting up or there's an intermittent short in the wiring. The cam sensor wires go from that connector in the pic to the X59 connector, then to the DME. Not sure why it always happen at the same rpm though.
Ahsai is online now  
Old 04-30-2019, 03:32 PM
  #11  
VFRMike
User
Thread Starter
 
Join Date: Dec 2016
Location: San Diego
Posts: 47
Likes: 0
Received 0 Likes on 0 Posts
Default

I'm hoping for it to be the sensor only. Considering how it only acts up when really warmed-up, and driving on a smooth surface...
You'd think if there was a broken wire or connector then rough roads would be a factor.
VFRMike is offline  
Old 05-05-2019, 03:16 AM
  #12  
VFRMike
User
Thread Starter
 
Join Date: Dec 2016
Location: San Diego
Posts: 47
Likes: 0
Received 0 Likes on 0 Posts
Default

I was finally able to spend a little time poking around. With the airbox out, I could see the sensor and connector on the driver's side cylinder head. I was able to unplug the connector, and it was "wet" inside. With what, I cannot tell. Next I want to remove the sensor, but haven't figured out how to get a wrench to the allen head bolt holding it in. It seems as if I'll need to support the engine and remove the carrier plate to gain access.
VFRMike is offline  
Old 05-05-2019, 03:23 PM
  #13  
VFRMike
User
Thread Starter
 
Join Date: Dec 2016
Location: San Diego
Posts: 47
Likes: 0
Received 0 Likes on 0 Posts
Default

OK, with the help of a stubby 5mm 1/4" drive, I was able to extract the old sensor. It appears to be full of oil. I have a new Bosch sensor going in, we'll see what happens...

VFRMike is offline  
Old 05-05-2019, 05:54 PM
  #14  
Mike Mullins
Addict
Rennlist Member
 
Mike Mullins's Avatar
 
Join Date: Jul 2002
Location: Cincinnati, OH
Posts: 604
Likes: 0
Received 2 Likes on 2 Posts
Default

I'd say Sensor has deteriorated and is wicking oil back to wiring connector head, I had similar on my MB, II went ahead and replaced , Later Crankshaft Sensor went, giving same symptoms, intermittent firing after warmed up. replaced. Runs like new.
Mike Mullins is offline  
Old 05-05-2019, 07:09 PM
  #15  
Ahsai
Addict
Rennlist Member
 
Ahsai's Avatar
 
Join Date: May 2005
Posts: 7,281
Received 2 Likes on 2 Posts
Default

You may want to use contact cleaner to clean the electrical socket thoroughly before plugging it to the new sensor.
Ahsai is online now  

Thread Tools
Search this Thread

Contact Us - About Us - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: