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Truck still runs great but the code comes back once the truck reaches normal operating temp.
So the code never appears until it’s at operating temp? And consistently comes back each time?
My mind is wondering in a couple directions for this specific point.
1- is this something of physical aspect which does not occur until it’s warm?
2- or is it not showing up because the PCM isn’t monitoring for a code until it’s warm?
3- or does the PCM use a different operating condition once warm which is throwing the code?
To check this, I wonder if you could trick the PCM into not seeing warm EOT condition? No warm sensor=no code or vice-versa then it might point you a direction. 🤷♂️ Just a thought.
So the code never appears until it’s at operating temp? And consistently comes back each time?
My mind is wondering in a couple directions for this specific point.
1- is this something of physical aspect which does not occur until it’s warm?
2- or is it not showing up because the PCM isn’t monitoring for a code until it’s warm?
3- or does the PCM use a different operating condition once warm which is throwing the code?
To check this, I wonder if you could trick the PCM into not seeing warm EOT condition? No warm sensor=no code or vice-versa then it might point you a direction. 🤷♂️ Just a thought.
Interesting theory at the least. Lets fool the PCM so we can fool "The Man". I like it. Damn "The Man"!!!
The 50-state (Californicated) calibrations substitute the cylinder contribution codes that show up during a key on, engine running test for a continuous code for cylinder misfire. Basically turning a code that wouldn't normally turn on a check engine light for one that does. Pretty typical tax money sponge alphabet soup agency operation.
Failing a #8 cylinder contribution test on a Federal emissions truck is usually nothing more than a, "Huh. Runs fine and ignore it." deal because nothing seems wrong with the thing until running an actual test for it. 50-state PCMs continuously monitor it and in this case you're being screwed.
Do you have any idea what your PCM box code is (or better yet the actual calibration code)?
Can this really be done reflash the PCM to ignore a code? and if so what do I need to buy to program/reflash the PCM?
If the replacement camshaft sensor doesn't fix your [probable] non-issue, my offer stands. Send me the PCM and I'll fix that pesky code for you....free of charge of course so it didn't really happen.
Thank you, I will get a black CPS. If it fixes the problem then done deal. If it does not I will I will send you the PCM and say thank you ahead of time. Regardless I will post results so this thread can be closed if needed.
Anyone recommend where I can find the black CPS to purchase?
Thank you, I will get a black CPS. If it fixes the problem then done deal. If it does not I will I will send you the PCM and say thank you ahead of time. Regardless I will post results so this thread can be closed if needed.
Anyone recommend where I can find the black CPS to purchase?
Maybe I'm missing something, but cylinder 3 and cylinder 8 failing a CCT is usually something to ignore, especially if truck is running fine without a miss or stumble.
Do you have a SES light on?
Fortunately I don't know anything about passing a smog test in California, but surely they don't run a CCT?
^^emphasis on this. 3 and 8 fail on mine all the time and I chased ghosts. I've seen threads discussing this being related to the new CPS
Failing a buzz test is more concerning. I failed buzz tests for weeks after replacing my injectors. I had three issues:
Loose connector on outside of valve cover. The locking clip wore out.
Loose connector on inside of valve cover. I could could read this on a meter. I returned that gasket.
Spread pins on cylinder 8 connector. I returned that gasket
Finally, I ended up shorting out my IDM when degreaser made its way past the gasket on the connector.
These are four issues that can give you a P0308, that AREN'T internal engine failures. Try swapping the connectors as well to see if the issue follows the circuit.
Note that the injectors run on roughly 115V AC, not 12V DC. I've had bad connections read 0 ohms
My statement came from a misreading of my oscilloscope (which I have very limited experience on), not regurgitating YouTube and forum posts. I just did some more research on why the voltage pulls negative. I just assumed I was getting a bad reading due to my limited scope skills or my cheap scope, and that is why it doesn't read like a sine wave. It's just the nature of a valve solenoid. I was wondering why the powertrain diag manual list this at 115V if that's the peak, and AC is usually measured in RMS voltage. DC would make more sense.
Anyway, the original point was to emphasize the importance of checking the circuit connections because I spent hours tracing through the circuitry to find each weak connection in both old and new parts. I'm following along with the PCM reflash too, I'm interested to see if that works.
