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It has a crank sensor but it’s probably a dealer only item cause it so new.
Just drive it and see if the codes come back..Well it sounds like an intermittent failure which means you may have to wait till it fails completely to find the cause. The crank sensor code as well as the misfire code might put it into ‘limp in mode’ which would give you limited power as you described. I guess drive it to see if those codes come back and take it from there.
Made it to work and back today with no issues that I could see.
As far as freeze frame data, I was watching some data at idle.
I’m doing this from memory…
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STFT was +10 I think
LTFT was +7Perhaps I was slightly lean? Maybe the #1 injector wasn’t firing.
The Cat was 672F and climbing.
One O2 sensor was .7 and another was .2 and they were bouncing up and down what seemed normally.
I was surprised the traction control light came on. I wasn’t going fast or turning sharp at the time but I was accelerating. Perhaps the Jeep uses the TC system to slow you down for limp mode.
I could have those numbers reversed though…
My cheap cable / software doesn’t support the really good stuff like Mode 6, but it gets the job done for the most part.
Just thought of something… P0315 is crank sensor related… What if you had a Cadillac Sixteen car that had a misfire on cylinder 15? What should the code be?
Is the vehicle still under warranty?
It would have been interesting to look at freeze frame data.
Let us know if the codes and issues come back as the best way of testing a crank sensor is with a scope.
Update: It did it again, I was turning a corner in the parking lot at work and it stalled. Now it’s limping again.
I can feel the misfiring and if I keep going the CEL starts flashing and I get a “jake brake” sensation. I didn’t have my laptop with me so I couldn’t clear the codes.
I pulled the ECM harness for about 5 minutes but that didn’t clear it.
If anyone has access to a Jeep Patriot / Jeep Compass / Dodge Caliber engine layout can you tell me where the crank position sensor is?
EDIT: Some googling got me a diagram.
Found a copy of the factory service manual. And it had this to say about the codes:
P0315: No Crank Sensor Learned
First off the ltft and stft were requesting + 12% more fuel above the norm of + or – 5% indicating a lean condition.
Secondly, I am not sure if you should pay any attention to those figures while the vehicle is in “Limp” mode for a crank sensor code.
Third, The crank sensor should not be ignored and should become priority 1 before you do anything. I would purchase the one from the dealer for quality alone.
Lastly, Without a labscope you can only “guess” that the crank sensor itself is bad because in order to rule out the tone ring, pcm control and circuit integrity you would have to view the signals with the scope in managed real time images and then make a diagnostic decision based on those readings.
Yeah the factory service manual has some pretty in depth diagnostic procedures. It was 5,800 pages!
Also interesting, the RockAuto part was made by Airtex/Wells and has an attachment from Airtex that says:
“To prevent false misfire detection by the computer system, a Crankshaft Variation Relearn procedure must be performed whenever the PCM is replaced, or if the crankshaft or the crankshaft sensor is disturbed. Utilizing a diagnostic scan tool, perform a computer “Reset” procedure followed by three closed throttle coast downs from 70 mph – 40 mph. This procedure will place the computer in relearn mode allowing Crankshaft Variation Relearn.”
I’m hoping their definition of a reset is just clear codes and not “take to the dealer” reset.
Right now I’m pulling P0300 and P0300 Pending. And have not gotten the 315 or 335 since the other day. I’m going to go down to the Dodge dealer and pick the CKP up. My Jeep is in a parking lot at one of my company’s buildings down the road from the main campus. (Behind a security gate and barbed wire) I figured it would be less obstructive for me to work on it there. I don’t want to try to drive it home 20 miles with constantly having to shut it off and restart it again every 2 minutes to stop the engine shudder.
There was a thread posted a while back and there was a poster with misfire code P0300. A crankshaft relearn procedure fixed the issue.
I would do a search. I cant remember if it was Shaun or Jacob who mentioned this and helped solve the issue.
I would never erase any codes before doing diagnostics though.
P0 300 is random engine misfire that could actually be a Crankshaft Variation Relearn only due to normal wear and tear on the timing chain.
Since you will be doing a relearn anyway, I would replace the ckp sensor if the vehicle has 100k or so.
And since we are on the topic of magnetic pick up devices with mini transistors, you may consider the cam sensor as well which in many cases chrysler uses the same sensor for both which would yield reliability and consistent starts for the future ahead.I would perform a good visual on the ignition components to see if there is a misfire problem.
Yeah I found at least 2 or 3 sensors on the vehicle that have the same plug as the CKP. They all appear to be the same as the CKP with a 90 degree bend.
There’s one on the head (the non-belted side) about 6 inches above the CKP and there’s one on top of the transmission that looks similar also.
I got it replaced and did the relearn procedure and it seems to have been resolved. I’ve just made a video documenting what I did and will post it shortly, it’s just taking a long time to upload.
Here’s the video of how I seem to have fixed it.
I’m with Jacob in that replacing the sensor might be a good place to start without access to a lab scope. That said I think it’s also worth mentioning that it happened the last time when you took a turn, this could mean that it’s a connection or wiring issue in that when you take a turn the body will flex and if you have a loose connection or wiring problem sometimes this ‘flex’ can cause the wire or connector to move just right causing the problem. It might be worth doing a ‘wiggle’ test on the wires and connectors related to that circuit just to be sure it’s not something like that that’s causing the problem.
Yeah, see the video above, I did change it, and also I was thinking about the possibility of a short considering this is right by the exhaust manifold.
I know you and other guys talk a lot about throwing parts at a problem and I did weigh my options and at $23 that was more than worth the possibility of it dying out on the highway again and limping home with the engine violently shaking or needing a tow.
From the FSM it made more sense. One code only trips during deceleration which is exactly when it happened both times.
I had an old Dodge Stratus years ago that had a intermittent wire short that combined with bad mounts (or maybe because it) caused the O2 sensor wire to make contact with the exhaust heat shield sending the engine to 2500RPM suddenly without warning.
If you sat and revved the engine, it would literally look like it was jumping out of the hood at you
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