Quick advice for a French owner struggling with P0340 code

Maverick26_Fr

Maverick26_Fr

New Member
Joined
Jul 16, 2023
Messages
20
Location
France
Hello US TJ World !

I am strugling since many months to fix an engine starting issue with error Code P0340 (no signal from Camshaft sensor)

No ignition.

I have done the following:

- Buy a ODB II reader : Done => error P0340 appears each time I start to run the engine
- Cranckshaft position Sensor Replaced with the same 560 XXX part : Done !
- Camshaft position Sensor Replaced with the same 560 XXX part : Done !
- Read TJ Reparation Manual and how to diagnose P0340 issues : done !
- Check +5V on sensors : done !
- Check good ground negative : done ! (less than 1 Ohm)
- Check Wiring between PCM and both sensors (Crankshaft and Camshaft position) : done !
- Check Temperature sensor on Magnifold and coolant liquid : done ! (no short circuit and 10 KOhms for both)
- Check Distributor Finger : done!

BUT..

I have realised yesterday that the distributor finger is always in the same position even after many tries to start the engine (the starter motor run well)

Finger

So I would appreciate some help to answer some questions:

- Is there any kind of clutch release mechanism which should explain this? Maybe the finger stays static even when the starter run?
- On which bolt part can I try to engage manualy to make the motor go ahead slowly to check if the finger moves?

My wondering : there is probably a defective part inside the Distributor which would have cause the disconnection from the camshaft gears. Can this appear?

Thanks a lot for your advice

Jerome

My post on the FR - Forum :
https://www.jeepmania.com/Forum/viewtopic.php?f=40&t=87435&start=30
 
Good job on the thorough troubleshooting so far.

The distributor "finger" (we call it a rotor 🙂) definitely should spin while cranking. If you haven't already, crank with the distributor cap removed to confirm, and if it's really not turning, remove the distributor to look for a mechanical issue.
 
Good job troubleshooting this far. When you say distributor finger, do you mean the rotor inside the distributor? How did you determine it isn’t spinning?

Taking out the distributor isn’t hard, but getting it back in just right can be a bit of a trick. So tread lightly at first: If you remove the hold down clamp under the distributor you will be able to lift it up out of the hole. The rotor should turn like 15* as it comes up….does it? At this point you can push it back down without worrying about anything else.

But if it’s not spinning I would probably pull the whole distributor out and examine the gear and also look down into the hole to see the corresponding gear on the cam shaft. If the diz isn’t spinning it’s probably because those gears aren’t meshing for some reason.
 
Take the diz cap off and crank the engine. Take a video of the “finger” and post it here.
 
  • Like
Reactions: Rickyd
hear said:
Good job troubleshooting this far. When you say distributor finger, do you mean the rotor inside the distributor? How did you determine it isn’t spinning?

Taking out the distributor isn’t hard, but getting it back in just right can be a bit of a trick. So tread lightly at first: If you remove the hold down clamp under the distributor you will be able to lift it up out of the hole. The rotor should turn like 15* as it comes up….does it? At this point you can push it back down without worrying about anything else.

But if it’s not spinning I would probably pull the whole distributor out and examine the gear and also look down into the hole to see the corresponding gear on the cam shaft. If the diz isn’t spinning it’s probably because those gears aren’t meshing for some reason.
Click to expand...

Thank you for your message :)

I mean the rotor :) (Thanks Freedom_in_4Slow). I guess that it's not spinning because each time I have opened the distrib cap (probably 10 times since some weeks), I can remember that the finger was in the same position.. weird..

As proposed too, I will try to remove the cap and make a movie during the cranck. Then, if it doesn't spin, I will try to do what you said.

Thanks :)
 
freedom_in_4low said:
Good job on the thorough troubleshooting so far.

The distributor "finger" (we call it a rotor 🙂) definitely should spin while cranking. If you haven't already, crank with the distributor cap removed to confirm, and if it's really not turning, remove the distributor to look for a mechanical issue.
Click to expand...

Thank you :) I will post the result within a couple of days :)
 
Maverick26_Fr said:
Thank you for your message :)

I mean the rotor :) (Thanks Freedom_in_4Slow). I guess that it's not spinning because each time I have opened the distrib cap (probably 10 times since some weeks), I can remember that the finger was in the same position.. weird..

As proposed too, I will try to remove the cap and make a movie during the cranck. Then, if it doesn't spin, I will try to do what you said.

Thanks :)
Click to expand...

It does seem like a big coincidence to end up in the same place but I've seen weirder things, so it's best to make certain before taking stuff apart.
 
  • Like
Reactions: Rickyd
Or you can just have someone else watch while you crank the engine with the distributor cap off. If the rotor doesn't spin, you probably have a worn or broken distributor gear.
 
  • Like
Reactions: Rickyd
Another thing to check: trace the wiring from the sensor to ensure it is not broken. That is the same side as the exhaust, and if you have replaced the sensor and are still receiving the same error, I would highly suspect the wiring connection is interrupted somewhere.
 
  • Face Palm
Reactions: hear
glowell222 said:
Another thing to check: trace the wiring from the sensor to ensure it is not broken. That is the same side as the exhaust, and if you have replaced the sensor and are still receiving the same error, I would highly suspect the wiring connection is interrupted somewhere.
Click to expand...

He noted that he'd already checked that in his first post.
 
Distributor/cam gears are a good place to check if it won't rotate.then timing chain.

Welcome to the forum! Lots of knowledgeable people here.

Btw is that a mastiff strapped into the pass seat?(😆) cane corso?
 
Rickyd said:
Distributor/cam gears are a good place to check if it won't rotate.then timing chain.

Welcome to the forum! Lots of knowledgeable people here.

Btw is that a mastiff strapped into the pass seat?(😆) cane corso?
Click to expand...

hello @All :)

In the end, as you can see below, the rotor seems to work well. The fact that it always stopped in the same position previously must have been a coincidence.

I have been advised too to check the ignition coil (expected data : 1.2 Ohm on the primary, and 13 KOhms on the secondary) => I will check by the end of the week. But this would mean that the P0340 error code is arbitrary?

I will try too to provide a 5 V on the camshaft position sensor and ensure that my brand new sensor is working well.

I have previously replaced the Crankshaft position sensor, maybe I should to the same test?

Thank you for all your help, nice forum and skilled members!

NB: yes! Cane Corso who will soon take driving learning session if the Jeep start again one day..
 

Attachments

  • IMG_5659.MOV
    14.9 MB
You can test the crank sensor the exact same way as the cam sensor, they work essentially identically.

It sounds like you know what you're doing, but here is a video I did to bench test as well as integration test a newer style cam sensor. The old style works exactly the same way, but note that the wiring on your 97 is slightly different than what I have in my video (which was on an 02). Here is the pinout for a 97.

v85Wk6j6_87XFY9TMp1S2KhVTcL8Q3O3rkzh0nDFyf8JYtULmQ.png


 
  • Like
Reactions: Rickyd
Hello
Just to update!

hear said:
You can test the crank sensor the exact same way as the cam sensor, they work essentially identically.

It sounds like you know what you're doing, but here is a video I did to bench test as well as integration test a newer style cam sensor. The old style works exactly the same way, but note that the wiring on your 97 is slightly different than what I have in my video (which was on an 02). Here is the pinout for a 97.

View attachment 442426

Click to expand...

Hi

Thanks :)

I think that the wiring is the same, but the pin numbers are inverted on mine.

So, to update with latest news: I have checked the ignition coil, it seems to be good with 1 ohm on the primary and 12kOhms between High voltage and primary pins. I will replace it by security in case if this is a little isolation issue in the coil which could make a shortage.

I will now follow with a test , as you have done on yr movie, of both position sensors (cranck and camshaft) even if they are brand new.

IMG_5622.jpeg
 
  • Like
Reactions: Rickyd
So based on the quality of the typesetting of your FSM scan, I have my doubts about that being the FSM for the 97. The later years used that typeset, but the 97 is decidedly more primitive. Can you look at the beginning few pages of what you have, specifically the section that decodes the vin? It will tell you what year you have. There was a time when the 97 FSM we had posted here was actually for the 02 or 03, although it looks like you have a physical copy...

Also, while 97's are particularly quirky, that connector is not the cam sensor connector on any 97 *that I have looked at*.
 
Top Bottom
Back