'02 Saturn SL2 1.9 SOHC cam position sensor code

Discussion in 'General Motoring' started by Jeepkeys, Aug 29, 2024.

  1. Jeepkeys

    Jeepkeys

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    I am currently working on an '02 Saturn SL2 with a SOHC 1.9l engine. The car has about 60k miles on it and is in very good condition. The engine seems to run flawlessly. The check engine light has been on for at least a year or more, I don't know for sure how long because it's my friends car and he bought it with the light on. I understand that the SOHC version of this car has no cam sensor but uses the ignition pulses to determine cam position. I have done a lot of research on this issue and have replaced all of the ignition system(with new saturn branded ac-delco parts). I have also went through the harness wires and grounds, thinking there may be a short or corrosion, however neither of those was found to be an issue. I bought a used ECM from ebay for the year/make/model/transmission but none of the dealerships will reprobram it b/c it is too old. The only option for reprogramming is mult-hundreds of dollars and you would have to send the computer out via the mail. All in all this problem has me stumped. My friend is livid since he spent all his available money on parts I recommended to him, and I have not solved the problem. I feel like an asshole, but I am just going with the information I have. As of now, the problem still persists- The check engine light comes right back on within a few minutes of clearing the code. The cam position sensor code is the only code that comes up, nothing else. I have scanned it with 2 of my scanners and have had it scanned at a local shop as well, all could only see one code- the camshaft position sensor code. My friend needs to get his car inspected(in NY) and is not able to until this code is gone. Is there anything else I have missed. All the info online says it is one of the things I have already replaced, so if it's not one of those things, what else could it be? The only thing I can think of is the computer and replacing that comes with it's own set of issues. And, as I stated earlier the car runs flawless- no perceptible misfires or stumbling, plenty of power, good fuel economy, etc. I am at a loss. Please help.
     
    Jeepkeys, Aug 29, 2024
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  2. Jeepkeys

    Derf

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    P0341 CMP indeed on a Saturn S car does not refer to a cam position sensor because there is none.

    Since it's a waste spark ignition system, each plug fires on the compression stroke and the exhaust stroke.

    On the exhaust stroke, the polarity is reversed and the spark jumps from the ground electrode to the center electrode.

    These engines were designed for copper plugs and copper plugs alone. Platinum and iridium plugs didn't exist
    The center electrode on Platinum and iridium plugs tends to wear unevenly. This creates an unstable waveform when the spark occurs. If the PCM sees something out of the ordinary, it usually sets this code. Often it will think it is also a misfire, but apparently it is subtle in your case.

    This can also happen If you use the wrong copper plugs.

    For SOHC, The OEM stock plug set of four is NGK 7755. That is from memory, please confirm.

    There are people on eBay selling what they claim to be OEM ACDelco plugs that work for both the SOHC and at the DOHC. It's simply not true, and depending on which plug they are selling, it works for one and not the other.

    The other common thing that happens is you get corrosion building up on the ignition tower terminals and the spark plug wire boots that attach to them. Cleaning them off with some emery cloth works wonders as long as you don't bend the contact inside the boot. I think you said you got new wires I can't remember if you said you got new coils.

    If you go to rockauto.com, which I suspect you know about, you will see every plug under the sun listed as compatible with an S series vehicle. Only one says OE.

    Sometimes the PCM isn't as picky and people run platinum plugs with no problem. Why? Don't know and never will.

    Again, please report back with results. Otherwise nobody learns from your experience

    Please post back.
     
    Derf, Dec 1, 2024
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