Go Back   DodgeForum.com > Dodge Cars > Dodge Neon
Sign in using an external account
Register Forgot Password?


Dodge Neon The sport compact car that took the world by storm. the Dodge Neon. Depending on the trim level you get, this sporty ride has something to offer everyone.

P0340 Trouble Code Help

Reply
 
 
 
 
Thread Tools Search this Thread
  #1  
Old 08-30-2010, 10:15 PM
killbassa killbassa is offline
Registered User
Garage is empty, add now
 
Join Date: Aug 2010
Posts: 4
Angry P0340 Trouble Code Help

Hello!

So I have been all over different websites and have determined that a P0340 code indicates problems with the camshaft position sensor circuit. I have a 2002 Dodge Neon with 130,000 miles that will not start. It cranks over easy for awhile and then it sounds like the starter is working harder. Not sure what that means.

Anyway....checked the codes and only got a P0340. Replaced the camshaft position sensor and the car still won't start and is throwing the same code. Checked the wiring and the connector and it is good.

Does anyone know if the Neon has the crankshaft and camshaft position sensor on the same circuit. Could a bad crankshaft position sensor cause a P0340? Because the car will not start at all, should I guess the crankshaft sensor is bad?

Oh...and the car pressurizes the fuel rail, has no blown fuses and produces spark in all four plug wires. It did pop a couple times out the intake like timing was an issue.....can I put a timing light on this car and tell if the belt jumped a tooth?

I just don't want to do a timing belt, crank sensor, water pump, etc if I don't have to.

Anyone know where you can get manual information, pictures, exploded parts diagrams for this car?

Any help would be wonderful! Thanks!
This ad is not displayed to registered and logged-in members.
Register your free account today and become a member on Dodge Forums!
Reply With Quote
  #2  
Old 08-31-2010, 02:12 AM
sapporo sapporo is offline
Banned
Garage is empty, add now
 
Join Date: Jun 2010
Posts: 1,406
Default

and your sure it doesn't have a broken timing belt?

I use an oscilloscope to determine the cam/crank signals and if they are in sync.
Reply With Quote
  #3  
Old 09-01-2010, 03:21 AM
killbassa killbassa is offline
Registered User
Garage is empty, add now
 
Join Date: Aug 2010
Posts: 4
Angry Additional

I read additional information online about CPS circuit and determined that a vehicle will usually run with a bad camshaft position sensor but will not start with a bad crankshaft sensor. Is it possible that the car only needs this sensor and not a timing belt job?

I am not sure however, that the car does not have a slipped or broken cam belt....it is a possibility from the mileage. I pulled the plug out of the top of the timing cover and there appears to be a belt on the cam sprocket.

I really don't know how to figure out what is wrong with this car, I don't have a code reader and the locals won't lend one. The ignition switch trick only indicates P0340. If the PCM was bad would the PCM still give a code of P0340?

Somebody please help I don't know what is wrong with this car.
Reply With Quote
  #4  
Old 09-01-2010, 03:25 AM
killbassa killbassa is offline
Registered User
Garage is empty, add now
 
Join Date: Aug 2010
Posts: 4
Default Additional checks

Are there additional checks I can make to determine what could be wrong? I think I might put a compression tester on it to see if it builds vacuum. If it doesn't I will know the timing is off or there is valve damage.

Second, does anyone know if I put a timing light on the car....if I can check the ignition timing?

How do I check the crankshaft position sensor plug with a multimeter?

How do I check to see if the cam or crank signals are in sync?

Thanks!
Jeff
Reply With Quote
  #5  
Old 09-06-2010, 07:48 PM
sapporo sapporo is offline
Banned
Garage is empty, add now
 
Join Date: Jun 2010
Posts: 1,406
Default

well since you asked for an answer I already GAVE you post #2 answers how to check cam/crank signals are in sync

a compression test has no hold for vacuum, since compression is pressure and a vacuum is an absence of pressure.
Reply With Quote
  #6  
Old 09-06-2010, 07:58 PM
jbar1981 jbar1981 is offline
Registered User
Garage is empty, add now
 
Join Date: Jul 2010
Vehicle: 98 Dodge Durango
Location: Dallas Texas
Posts: 18
Default

Open the oil fill plug on top of the valve cover, have a friend turn the engine a few times, if you don't see any movement inside (With a flash light) your timing belt is jacked. I can guarantee you its the timing belt without you even doing that though because I have been going through the same crap on and off for the last two years with my stratus. Those belts are only meant to last about 60,000 miles. The sensors do go bad but they only make it run rough, If it won't start no matter what its the belt.
Reply With Quote
  #7  
Old 09-06-2010, 08:05 PM
sapporo sapporo is offline
Banned
Garage is empty, add now
 
Join Date: Jun 2010
Posts: 1,406
Default

so a crank sensor failure would allow it to still run rough?
Reply With Quote
  #8  
Old 09-06-2010, 09:32 PM
jbar1981 jbar1981 is offline
Registered User
Garage is empty, add now
 
Join Date: Jul 2010
Vehicle: 98 Dodge Durango
Location: Dallas Texas
Posts: 18
Default

Yes, it will just run rough and idle crazy.
Reply With Quote
  #9  
Old 09-09-2010, 01:32 PM
blacksunshine05's Avatar
blacksunshine05 blacksunshine05 is offline
Professional
Garage is empty, add now
 
Join Date: Aug 2010
Vehicle: 2005 Dodge Neon SRT-4
Location: San Angelo, Texas
Posts: 242
Default

Your timing belt could have broken. Pull the timing belt cover off and you will tell if the belt is broke.

And if your crank positioning sensor is dead your car will not start. And if it does start it will die a couple of mintues later. The PCM uses the crankshaft positioning sensor signal to determine engine RPM, crankshaft position, and engine firing order. This signal indicates the cylinder that is on compression and the PCM can determine from its programming the engine firing order. No crankshaft position sensor no starting the car because it does not know where the piston is.
__________________
Precision 6262SP Turbo, MAP Stage 5 Head, Brian Crower Stage 3 Cams Thread Build
Reply With Quote
  #10  
Old 11-08-2010, 01:32 AM
killbassa killbassa is offline
Registered User
Garage is empty, add now
 
Join Date: Aug 2010
Posts: 4
Smile Resolved p0340 trouble code

I just wanted to make a post to show how I resolved this problem. I know generally people ask for help and never post an update so that readers can learn from their experience. I didn't want to be one of those people; see below.

So the Dodge Neon 2002 I was working on was cranking over and not starting and throwing a P0340 trouble code. I thought about it a little bit and then I pulled the valve cover to see what I could find. I found that when I cranked the engine over the camshafts didn't turn.

I pulled the timing cover and found the timing belt had lost all the ribs at the bottom by the crank sprocket so the crank was spinning but not pulling the belt. I figured the engine was shot at this point because I know the owner had cranked the battery dead trying to get the car to start.

Nonetheless, I figured a $40 timing belt was worth finding out if the engine still had any compression. I timed and aligned the timing marks and installed a new timing belt. Ran a compression check and found that every cylinder inconsistently had between 160 and 195 psi. The car had 130,000 miles and I am certain infrequent oil changes so I figured what the hell. Maybe it will run.

I replaced everything worn out and broken and the car runs great. Or good enough for the owner. Thanks for all of your help and suggestions.

Additionally, having been through this car from top to bottom I have all kinds of assistance if you just ask. Thanks again!
Reply With Quote
Old 11-08-2010, 01:32 AM
 
 
 
Reply




Tags
camshaft, circuit, p0340, sensor, timing

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Forum Jump

Join DodgeForum
Advertising

Featured Sponsors
Vendor Directory
Our Sponsors
All times are GMT -4. The time now is 01:15 AM.

Internet Brands, Inc.


Contact Details & Emails