2002 Hyundai Sonata P0340

2002 Hyundai Sonata 105,000 miles, 2.4 L MFI DOHC error code PO340. have replaced timing belt, pluges and wires, both ignition coils, Camshaft position sensor(twice). Car runs fine till it warms ups. (About 10 miles) then it starts missing (at various speeds), check engine light comes on and goes off when accelerator backed off of. If you shut it off it may or may not start back up. If it does start it will run very rough almost like is flooding out. Last thing I can think to replace is the PCM.

Dont' replace the PCM, it's not necessarily the PCM. You've thrown every part at it you can think of, now let's diagnose it. Have you check the Camshaft sensor circuit visually? Any breaks? Don't say "no, it's fine" if you don't know for sure. After that, you'll need to check that circuit. There should be three wires: a power(supplies steady reference voltage always), a ground, and a signal wire(this is the camshaft signal and appears as a square wave. You'll need a scope to check it properly, though you can do it with a good voltmeter).
That code sets when the PCM detects an erratic CMP signal or no CMP signal at all. THat means there could be an open, or short in any one of those wires. Check them all. Post back results.

Are you sure the cam is timed correctly?

I had a similar problem with a 2001 Sonata. I had a spark on only one coil. The one I was working on had a coil divided in two. The timing belt was changed and the cam sensor was changed. Then I checked the circuit, it all checked fine. So we changed the computer which by the way is not cheap about $500.00. Well it did not fix the problem. To make a long story short, it turned out to be that the cam sensor that was installed at first was bad from the begining.
Oh and another thing, follow intallation intructions on the car manual to a T. Because if you are just one tooth over the car will have really high idle and the timing will not be correct. The trick for me was to hold both cams lined up while installing the bottom part of the belt. You will need a special tool to hold the cams in place and another special tool to turn the little tensioner on the belt, also dont forget to align your balance shaft.
One more thing, before anymore money or parts are put into this car make sure that you have good compression on all pistons. These cars are famous for having trouble with the head valves 'smashing' against the pistons if the timing belt was not aligned correctly. Good Luck!!

i think no one is listening on this thread!

Cam is timed correctly.

What about everything else we mentioned? wiring? Did you visually check the CAM timing?

Looking into the wiring now.

Have the exact same problem. Had the crankshaft position sensor replaced and after about 10 miles it still dies. Code p0340 and several cyl misses. No other work was done.



75k miles.

Any ideas?

Tom

Go back and read the posts and complete the diagnostic procedures, then post back.

Problem was a bad ignition coil for cyls 2-3.

Tom

Interesting, had an 02 with no codes, but stumbling problem after 15 min in traffic. Found a bad 1-4 coil so I repaced both, haven't heard back yet but another is here today with the p0340 code and cut out while driving, restarted after 5 min. Could be on to something?

Have the same problem with a 2000 Sonata. Light/Code says Sensor for the Crankshaft was bad, engine shut down after 15 mles/cooled and started for a little bit longer. Changed the sensor, timed it to the T (what a task). Now runs on 1 & 3. the #2 and 4 do have spark, change the coils manualy and cross them to the other holes and 2 & 4 fire. Also had it towed to Pep Boys to double check the timing, its ok but they can't figure it out ether. Funny thing, when I pull the Cam sensor no light comes on for a fault. As above, all wires look and check ok. Wondering if a short in the Control box would cause the same actions ?

Ok, had Pep boys do a complete Diao test. The plug wires ( coil pack wire where shorted and try this, the wires where crossed ). Cant figure that one as the coil packs and wires aren't really to crossable. Somehow in the reassy myself or the boy put a wire on wrong/bad wires made this thing act like the timing was off and or cam sensor was bad. Good luck with the process.. Diao test at Pep Boys $89.00, and I'm one that would never trust them.. go figure..