Chrysler Repair: Intermittent P0340 2.7 2002 Stratus ES, pulley bolt, crank pulley

Question
QUESTION: Car: 116K 2.7L Stratus ES.

Relevant work: Timing chain, cam & crank sprocket, water pump, oil pump (might as well), plugs replacement at 103K. Mileage about 26mpg as per the computer.

First incident: At about 113K, the car bucked (probably due to ASD) got code 1680 and P1591 intermittent cm or ck sensor signal. It was ok for about 30mi. Then I had to drive with it like that to get home and the problem got worse, eventually it chugged too much to maintain highway speed and had to pull over and got it towed home.

First repair: I replaced both cam and crankshaft sensors with aftermarket parts from Autozone. Cleared all codes and drove it again. The car idles ok if I start it and fully disconnect the battery. All harness wires seem ok. Compression ok at ~180 at all cylinders. Milege same as before incident.

New problem: code 1680 & 340 come back every 200 - 300 mi. Usually at startup, not necessarily cold.

I cannot figure it out! What could be the potential causes and how can I eliminate them?

thanks

ANSWER: Hi Oleg,
The i680 and 1591 codes don't seem to be related to the engine so I would set those aside. Because the 340 comes on at start-up what you might want to verify is that the signal from them cam sensor is as it should be when the engine is cold. Measure the voltage between the tan/yellow and the black/light blue wires at the cam sensor by probing at the pins of connector with a voltmeter. It should oscillate between 5v and 0.3v several times per revolution of the crankshaft, with the ignition 'on' and by turning the crank pulley bolt with a socket and ratchet. According to the manual though, it could be the crank sensor too so similarly check its voltage between the gray/black and black/light blue both sensors, in other words, between pins 3 and 2 of the plug. If the signals aren't firm, then reset the sensor with the tip touching the surface of its underlying sprocket. If you aren't having any driveability issues it may be something marginal. You may need to go through the details of the connections of each of the 3 wires of both sensors to the pcm using a continuity testor.
That is about all I can suggest.
Roland

---------- FOLLOW-UP ----------

QUESTION: Thanks, Roland. I'm going to check the voltages.  I meant 1684 not 1680. Do you think the 340 could be caused by a "stretched" timing chain or loose  chain tensioner?

I want to be sure about this to decide how long to keep the car.

Thanks

Answer
Hi Oleg,
The 1684 is just saying that the battery was disconnected sometime in the past 50-100 ignition key cycles.
I don't see how the 0340 would in any way be related to a timing chain or its tensioner. As long as the cam shaft is turning it would produce a signal. That is what the code is strictly about.
Roland
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