Engine code P0340

Tiny
VANETTENJOE
  • MEMBER
  • 2009 CHRYSLER PT CRUISER
  • 4 CYL
  • 2WD
  • MANUAL
  • 97,000 MILES
Engine code p0340 comes up. I have replaced cam shaft sensor and connector. I have put in new spark plugs and wires. I have added fuel injector cleaner and I have tried to reset the sensor by turning on the lights and taking the negative cable off the battery and waiting two hours. Please help!
Tuesday, January 5th, 2021 AT 3:23 PM

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Tiny
CARADIODOC
  • MECHANIC
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P0340 - Camshaft Position Sensor Circuit Malfunction

This code is different from those indicating an electrical defect related to that sensor. A better suspect, and a very elusive one, is the dowel pin between the camshaft and sprocket has sheared off, then the sprocket rotated on the camshaft a little. That makes cam timing late, and the camshaft position sensor is at the opposite end of the camshaft, so its signals are late too.

A different code for "cam and crank sync" will be set if the camshaft is late by the equivalent of one tooth on the sprocket. That will also turn on the Check Engine light. At the equivalent of two teeth, or if the timing belt jumped two teeth, the Engine Computer will shut the engine down to protect the valves. At three teeth or the equivalent on the sprocket, the open valves will be hit by the pistons as they coast to a stop.

This only applies to the single-camshaft engine, not the dual shaft model
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Tuesday, January 5th, 2021 AT 3:46 PM
Tiny
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I thank you so much for you answering back so fast to me. So you think it's the dowel pin. Now it's coming up as code p0335 and po340 it never did that before. And is this a hard fix to do. I appreciate your help i'm desperate right now. I hope this isn't a very hard fix.
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Tuesday, January 5th, 2021 AT 7:42 PM
Tiny
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P0335 - Crankshaft Position Sensor A Circuit Malfunction
P0340 - Camshaft Position Sensor Circuit Malfunction

I haven't run into this combination before. That suggests these codes set at different times, even though they are likely related.

The first thing to be aware of is there are different code numbers when the computer detects a defect with the wiring for a sensor. That would cause a loss of signal, resulting in these types of codes:

P0322 - Ignition/Distributor Engine Speed Input Circuit No Signal
P1359 - Crankshaft Position/TDC/Cylinder Position Sensor Connector Disconnection

The codes you listed only indicate the computer sees something it doesn't like about the signals, but they don't specifically say the signals were lost.

The dowel pin problem I described normally results in the Check Engine ight turning on, but at first the engine still runs. The same thing happens if the timing belt jumps one tooth. Engine performance will suffer, but it will still run.

It's when the timing belt jumps two teeth that the computer turns the automatic shutdown, (ASD) relay off to stop the engine, thereby protecting the valves. The fault code will be "cam and crank sync". Both sensor signals are showing up like normal, but not at the same time.

The camshaft position sensor and the camshaft sprocket are at opposite ends of the camshaft. That means the sensor's signal will be late regardless if the timing belt jumped one tooth or the sprocket slipped on the camshaft. This is where very experienced mechanics can become confused. We would normally remove the timing belt inspection cover, look at the timing marks on the two sprockets, and see they're still lined up perfectly. What we don't realize is while the sprockets are in perfect time, the camshaft is still a little late, thanks to that sheared-off dowel pin. I told you previously this only applies to the single-cam engine, not the dual-cam version. Now I see only the twin-cam engine was used in 2009 models, but if you look at the second drawing, you'll see they're still worried about that dowel pin. That warning about tightening the sprocket bolt with air tools was not included in the earlier years.

A very good friend of mine, (my former Automotive instructor), has a PT Cruiser, and he wanted to replace the timing belt for general maintenance. I can tell you this is probably Chrysler's most miserable car model to work on, and the job is a big one because so much has to be disassembled. I've posted the instructions first for removing the timing covers. That should be sufficient to check the timing marks on all of the sprockets to see if the timing belt has jumped. The last three drawings are for the timing belt itself.
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Wednesday, January 6th, 2021 AT 4:42 PM

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