[Gary Kline]

2019 Cherokee Limited 3.2. 63K. Went on a 400 mile trip today. On the way home a mile from the house the auto stop start warning starts beeping and the check engine light goes on. These are the codes. Is it a common problem, should I replace the camshaft sensor, or is there a bigger problem with the engine? Other than the startup rattles, there are no ticks. View attachment 232679

Hey @Tico007,

While it could be the camshaft position sensor going bad, many times that's just a code caused by something else.

Tell more about the startup rattle? When does it happen and since when? Any chance of recording a video of it? The reason I ask is that:

1. If one of your cam phasers is bad (not locking to the camshaft when its supposed to) it could make this type of error.
2. Also, the V6 has oil gallery screws that have been known to back themselves out causing low oil pressure. This can also affect the VVT operation and cause an error like this. Unfortunately, the only way to check them is to take the head cover off and check the tightness of the two screws (two per head). Checking the phaser involves trying (gently) to move the camshaft with a crescent wrench and if it moves significantly, the phaser is bad. In your case, Bank 1 nearest to the firewall.

And of course the usual check the health of the battery (get a free battery test) and check your ground strap etc. You've probably seen those posts here.

One less invasive thing you can do is swap your camshaft position sensors and see if the error travels to the other side (Bank 2). If so, that's a pretty strong indication that maybe the sensor is bad but if not, I'd look at the phasers, oil gallery screws next. By the way, also just make sure the CPS wire is on solid (through I assume it it b/c if it weren't, you'd probably see this error more but to be certain, unplug and plug the wire back into the sensor. (you'll need to take off the upper air intake to get to it I think though.)

 

[Gary Kline]

The light start up rattle lasts for 3–4 seconds after the engine starts cold. It’s done it as long as I have owned it. My understanding is it’s because the oil filter housing lacks anti-drain back so it’s considered normal for these engines. During operation it’s totally quiet. I use penzoil ultra platinum 5w20. it’s currently at 65% oil life. It’s full doesn’t consume any oil.

Should I try clearing them?

The light start up rattle lasts for 3–4 seconds after the engine starts cold. It’s done it as long as I have owned it. My understanding is it’s because the oil filter housing lacks anti-drain back so it’s considered normal for these engines. During operation it’s totally quiet. I use penzoil ultra platinum 5w20. it’s currently at 65% oil life. It’s full doesn’t consume any oil.

Should I try clearing them?

Re: clearing the codes, yes. I always clear at least one time to make sure it's more than a one-time thing. (though as you have permanent AND pending codes, I bet it will come right back)

 

[Gary Kline]

@Gary Kline I cleared the codes and yes, the P0340 permanent came right back. Assumption is I need drive cycles. Oddly it did have an extended crank to start the first time after clearing. Subsequent starts our normal. Just the CEL no complaining about auto start stop disabled anymore. Is there any type of relearn I can do for this? I do have alpha.

I don't think drive cycles will matter at this point. Assuming your battery/ground strap/IBS sensor have been checked, I'd probably look next into;

(a) confirming the wire on the sensor connector is secure (unplug and plug back in, erase codes and restart) or if it seemed like the connector was tight
(b) go for the swap of the Bank 1 and 2 sensors and see if the problem follows the sensor or stays with the Bank.

(c) I'd still like to know more about that rattle sound but one thing you could do is a phaser cleaning cycle on Bank 1 (and also Bank 2 since doing it anyway). They're in AlfaOBD under the diagnostic tools. You will hear the engine run rough during the cleaning. This is normal but if a phaser ic clogged with debris, the clearning cycle sends high pressure oil through to clean it out (best it can)

 

[Gary Kline]

Actually.... skip the last part of the phaser cleaning. Now that I think about it, I don't think it will let you (it might say it can't do it if you already have a CEL light on...)

You can do a cam-crank re-learn however I'd still do (a) and (b) above first before changing anything so you'll know which helped/did not help the issue. (not changing too many things at once)

 

[Gary Kline]

For piece of mind.. these parts are favorites on rock auto. Cheap enough. Suppose I should have them just in case. If this brand is OK. View attachment 232694

Hi @Tico007,

Are you doing the work yourself? Note, replacing a crankshaft position sensor is difficult. It's on the rear side of the engine in a tough-to-access location. However, it's almost unheard of for both sensors to go out (and again, I doubt you're having a problem with your sensors but if you did, the camshaft position sensor is the one that could be a candidate for replacement if any)

 

[Gary Kline]

Yes I can DIY. I don’t plan to shotgun the parts just want to have them. The plan right now is drive it and see it permanent code clears. If it doesn’t or comes back, swap the sensor locations. If it moves, use the new camshaft sensor. If it continues to be that bank, open the valve cover and check the bolts. At that time do the oil cooler gaskets.

I do have an extended warranty. Engine and drivetrain is covered. Not sure about electrical parts. It’s a $200 deductible so I figure take a shot at it. if it doesn’t work out, take it to the dealer. It has another issue that needs to be looked at. It’s binding when you take a sharp left and accelerate.

Perhaps check with the dealer and see if this would be covered in-warranty (always best to put it on someone else's back where possible )

 

[Gary Kline]

Update: I was able to clear the permanent code using AlphaOBD. Then poking through the menus I found a “cam/crank relearn” command. That did something because the idle changed for a while. Gong to let it sit, try starting later take it for a ride.

Yes, this is what I mentioned in the earlier post I would wait until you actually swapped the sensors as the existing two camshaft sensors and the crankshaft sensor shouldn't go out of relation with each other unless something has changed or there's an issue. If it's done, it's done. Keep an eye on it and then check if you have the warranty for this. If not, you can start with the parts-swap (or replacement sensor) and then bolt/phaser check etc.