P0138,P0325,P0340 where to start.

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crazy_dave

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P0138-O2S ckt high volts 1 2

P0325- knock sensor 1 ckt malfunction bnk 1 or single sensor

P0340-cam position sensor A bnk 1 ckt malfunction

What the hell does all this mean and where do I start.
This is all from a 02 sunfire with the regular 2.2. I have been getting a code, can’t remember what the P???? is but it was for the knock sensor. Not the above Knock sensor code with the malfunction bnk1 but just a plain knock sensor. This time when I went to check the code I got these three and Ive never seen them before.
How do I start troubleshooting these? Any help would be greatly appreciated.
 
I'd start by checking the operation of the rear heated o2 sensor. Yup, the expensive one that is located just aft of the CAT.

If that that sensor fails to send the proper signal to the PCM, the PCM will keep the fuel system in what's called open loop. The PCM should give the engine a richer mixture while operating in open loop, and richer means more unburnt fuel. Also, has any recent work been done where silicone sealant been used on any part of the engine. Silicone can kill an o2 sensor. If the o2 sensor has a white fluffy substance on the tip, most likely it has had an encounter with a contaminate.

The knock sensor detects detonation (pre-ignition) which is mostly found if the engine is running with the timing advanced to far. Detonation can be caused by other factors as well. Cheap fuel, incorrect engine operating temperature, etc.. When the knock sensor detects a problem, the PCM adjusts the timing to compensate.

The PO340 does not come up in the FSM, are you certain the code was PO340?

Basically, the sensors need to be checked for proper continuity, and function. If all sensors, and their circuits check as being good, the PCM needs to be replaced.

But...Its pretty rare that a PCM fails, so make darn sure the PCM is bad before replacing it. And, further more, most times, if the engine is still running on all 4, replacing the PCM does not fix a problem such as this.

If your physical location is in an area like Detroit, Milwaukee, St. Paul, etc., check the wiring and connections for corrosion.

From what I can see from reading the FSM, none of these sensors are related, in that, if one failed and set a code, the others would not follow suit. Each of these sensors monitors a different area of operation. The o2 has nothing to do with the knock sensor, and, if the cam sensor is involved, there's no relationship between it and the other 2 sensors. Each has detected a problem unrelated to the others.

Good luck.
 
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Oh sweet Jesus this is going to be fun. Im in upstate NY btw.Ill check the wires.
 
Anyone know how changed the Knock sensor on a 2.2 Sunfire. How the hell did you get to it?

Any help would be greatly appreciated.
My email is freeride772001@yahoo.com
Thanx
______________________________
 
found this hope it helps

2.2 is on back of engine block.When you are laying under the engine looking up,its on the right side screwed into a boss thats cast into the block.The thing is around 2" around with a rather large plastic plug snapped over its mushroom shaped connector.It just threads in,nothing will leak out.Be careful removing the connector,its tough to get off.Use a blade screwdriver,put it under the connector and twist.Then turn the connector 180 degrees and do the same twist with the screwdriver.It will come off without breaking.
 
Thank you very much. Now I just have to find away to get at it lol.
Its going to have to be from the passenger side with the wheel removed or I can try from the top down. Either way it looks like it’s going to be a PITA.
 
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