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Cai + Pcm

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So I bought a Volant CAI and Wheatley tuned PCM.


I disconnected my battery, and put in Wheatley tuned PCM (which i had tuned expecting the cold air intake to be installed), reconnected the battery. I put my key in, to do the security procedure (try to start, leave it on for 11min, etc), but when I started it up, it just worked. There was never a problem. Confused, I decided to just keep going and worry about it later.


I took out the stock air intake, and put in the volant. I worry a little bit because the piece that hooks the intake into the head is hard plastic, and so the tightener has trouble tightening it very much. (But not too worried about this).


So anyway. I start up the truck, rev it a little and it works great.


I get out onto the road and notice two things. There was a SES light on (no idea if it had been there since the start, or if it had just appeared). Second, is my speedo is way off. Around 10% off, and seems much worse around 0-30mph. The truck seems to run great, the engine idles great, it pulls hard on acceleration. The whole powerband sounds fine, so I can't figure out what the SES light is for. If it was a temporary problem, wouldn't the light turn off after a while?


I ended up driving the truck back to my place (bout an hour away) and the truck ran fine the whole way. Anyone have any advice as to what could be wrong? My only thoughts are


1. Something wrong with the PCM tune.

2. I somehow broke the MAF (but then wouldn't the engine run crappy?)

3. Somehow air is getting in after the maf making the mixture just a TINY bit lean, enough to throw a light, but not enough to affect driving?

4. Something wierd that happened because I changed two things at once, and the PCM flipped out for a second relearning and made a code that won't clear itself.


Thanks for the help

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First off, you need to get that SES light scanned to see exactly what it is before you determine it is the PCM. Many auto part stores will do this for free. Charlie can correct your speedo also, how do you know it is 10% off normal?

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It took like 65 seconds to do 1 mile on the road @ 60mph. The 10%( is an estimate based on that and observed/actual speeds of cars on the highway as well.


I will head down to a local parts store to get the code read, and will update here :)


P0315 - Crankshaft Position System Variation not learned.


Apparently from what I can read I have to go get some kind of scanning tool, and put it in CKP learn mode, and then go to WOT, so that the engine can relearn tolerances for the variation in the sensor and crankshaft.



The crankshaft position (CKP) system variation learn feature is used to calculate reference period errors caused by slight build tolerance variations in the CKP sensor, crankshaft, and CKP sensor position. The calculated error allows the engine control module (ECM) to accurately compensate for reference period variations. This enhances the ability of the ECM to detect misfire events over a wide range of engine speeds and load conditions. The ECM stores the Crankshaft Position System Variation values after a learn procedure has been performed. If the actual crankshaft position variation is not stored within the CKP compensating value look up table, then DTC P0300 may set. If the CKP system variation values are not stored in the ECM memory, or a proper ECM power down does not occur after completing the CKP Learn Procedure, then DTC P0315 sets.


So would just resetting my computer, and the just redoing the learning work?




Edited by JokerSP3 (see edit history)
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Did you do the actual crank relearn process? Or just try to reset computer? On this site are the directions for crank relearn.


I have not done the crank relearn process. I am not sure how to do it. I have seen directions once I have a scanner tool, but I am unsure of which scanner tool to use, and once I have it, what buttons do I press to start the process?


Also, I called a few dealerships in the area to see what they charge me to do it and they say $100 - $200... screw that.


I found a procedure online to do it by accelerating and decelerating over and over for about 20min. I may try that tonight to see if it works.

Edited by JokerSP3 (see edit history)
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  • 2 weeks later...

Hey, did you ever get this sorted out? My truck threw the same P0315 code yesterday. It seems to run fine, but the check engine light won't go out. I tried resetting the DTC with my Aeroforce Scan Gauge, but it won't reset.


I found a relearn procedure in this post:


Old Post


It is pretty old. Is this still a current way to do a crank relearn?


Help :)



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I had the same problem. P code 0315. I called Charles Wheatley and he told me to take it to a shop with a Tech 2. I took it to my local garage I use and got it fixed in about a minute. They didn't have a Tech 2 but they used a Snap On diagnostic tool. It actually took longer to input the trucks info into the computer than the actual crank re-learn procedure. They turned on the ignition waited a bit, started it, hit the gas a few times and that was it. The mechanic wouldn't even charge me it was so quick.


In case anyone is interested in knowing, Charles said that the P0315 code basically means that the engine won't be able to tell if there is a misfire. Other than that he said the engine will run fine.

Edited by dkkustoms (see edit history)
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