Help with P0340 and P1391

deadrubberboy

deadrubberboy

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Jul 9, 2018
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Orlando
Hi Jeepers...

Have a 1999 Wrangler 4.0 "TJ" w/ 150k ish miles. Had to crank a few times to get it to start recently. Only happened twice 1 day about a week ago and not again since. However the check engine light has come on since then. I read the codes with a cheap-o OBDII reader and got P1391 and P0340.

Google tells me those are the Crankshaft and Cam position sensors. My questions: where to start? It seems odd they would both go bad at once right? I reset the codes and a few days later they come back. No stalling, or hard starts at all since the one day I mentioned about a week ago.

I called the local dealer and parts guy says one of the sensors is part number 68881723AA - and that it's discontinued. I've consistently read that I should not use aftermarket when it comes to sensors. He advised there is no replacement and I would have to go aftermarket...

I also read that I should go ahead and do the whole distributor vs. just the sensor due to the cost difference and "you'll be in there anyway".

Does all of that make sense? Should I start with one or the other? Just do both? Something else entirely? The Jeep is my wife's primary vehicle and I don't want her stranded or anything.

Thank you for any help and/or guidance!
 
I'd replace the CPS and see if that corrects the CAM issue. If not, go ahead and replace both.
 
Thank you tworley,

That's the part that local dealer said is discontinued. I see aftermarket options on Amazon. Any experience with best brand to look for?
 
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deadrubberboy said:
I saw this one, but it indicates on the listing and in the comments that it's only for automatic transmission. Is that accurate? The manual trans one is different? My Jeep is a 5 speed manual.

Thank you again!
Click to expand...


Doesnt matter, the CPS sensor will work for an auto or a manual.
 
tworley said:
Doesnt matter, the CPS sensor will work for an auto or a manual.
Click to expand...

Update: cancelled Amazon order. I thought I remembered another thread also stating that there is a difference for manual vs auto. Called dealer (a different one from first time) and parts guy verified there IS a different part. Gave me part number 68407888AA and price of $125. That part number isn't available on Amazon but it is on ebay and other parts sites. Shopping around. Lowest so far is 85$ (includes shipping).
 
Sub'd for when you get it. A lot of part #s I have seen cross reference each other. We may have to update the how-to section.
 
Last edited:
deadrubberboy said:
I saw this one, but it indicates on the listing and in the comments that it's only for automatic transmission. Is that accurate? The manual trans one is different? My Jeep is a 5 speed manual.

Thank you again!
Click to expand...
I'm having a hard time keeping track of this. A code P0340 is for the camshaft position sensor, or CPS. The part number you indicate for replacement is actually the Crank Position Sensor (CKP)?
 
Sally Miller said:
I'm having a hard time keeping track of this. A code P0340 is for the camshaft position sensor, or CPS. The part number you indicate for replacement is actually the Crank Position Sensor (CKP)?
Click to expand...
I too am new/clueless about the codes. However, if you follow the thread I indicated that I'm getting 2 codes. I asked if I should address 1 or the other first, since my googling indicated they might be related and it seemed unlikely (but of course possible) that both sensors went bad at once. I was advised in the thread to start with the CKP first. That's why the part numbers/adventure is starting there.

Update: part arrived, haven't had time to address it yet though. However, the check engine light has sense gone off as well. Trying to avoid driving the Jeep for now until work slows down and we have time to try the new part.
 
Update: Check engine light went off and it's no longer hesitating. Haven't done anything. Have part on hand for when it rears it's head again. If/when that happens I'll update again.

Any ideas as to why / how it's seemed to have resolved itself?
 
Update: Check engine light came on again with same two codes (P1391 and P0340). This time it would "crank" but not start. Time to actually address this.

I still had Part Number 68407888AA-001 on hand (Crank Position Sensor). I researched youtube and it looked pretty easy. Most showed that it plugged in near drivers side under hood and attached at bell housing near passenger side. Multiple said that routing the cable and access to the bolts were biggest challenges.

Mine actually plugged in on passenger side under hood in direct line of site (from above looking down) to the bell housing. Super easy swap - took less than 30 mins. Cleared the codes and she cranked right up! Fingers crossed that neither code comes back. If so, I'll move to swapping the Cam Position Sensor next. Don't have parts yet.

Related Question (see pic for reference). It seems to me there should be a cover keeping you from dropping a screw or other debris from getting in the transmission. Sure seems like I shouldn't be able to see into there...

Can anyone confirm my google fu results that part # 53006010 (AKA "Clutch Timing Probe Grommet") is the piece I'm missing? It looks to me that it should do the job, I just can't picture in my mind how it attaches. I assume a previous owner lost it when swapping the same part?

ps. reminder: 1999 Wrangler 4.0 manual trans

97549
 
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deadrubberboy said:
Update: Check engine light came on again with same two codes (P1391 and P0340). This time it would "crank" but not start. Time to actually address this.

I still had Part Number 68407888AA-001 on hand (Crank Position Sensor). I researched youtube and it looked pretty easy. Most showed that it plugged in near drivers side under hood and attached at bell housing near passenger side. Multiple said that routing the cable and access to the bolts were biggest challenges.

Mine actually plugged in on passenger side under hood in direct line of site (from above looking down) to the bell housing. Super easy swap - took less than 30 mins. Cleared the codes and she cranked right up! Fingers crossed that neither code comes back. If so, I'll move to swapping the Cam Position Sensor next. Don't have parts yet.

Related Question (see pic for reference). It seems to me there should be a cover keeping you from dropping a screw or other debris from getting in the transmission. Sure seems like I shouldn't be able to see into there...

Can anyone confirm my google fu results that part # 53006010 (AKA "Clutch Timing Probe Grommet") is the piece I'm missing? It looks to me that it should do the job, I just can't picture in my mind how it attaches. I assume a previous owner lost it when swapping the same part?

ps. reminder: 1999 Wrangler 4.0 manual trans

View attachment 97549
Click to expand...
Is this the sensor you replaced?
https://www.amazon.com/dp/B07NSLFNLN/?tag=wranglerorg-20
 
(hopefully) Final Update:

Installed this fella to address the "open space around Crank Position Sensor". Fit perfect no complaints:

https://www.amazon.com/dp/B008VPUCX6/?tag=wranglerorg-20

Installed this guy: https://www.amazon.com/gp/product/B00VVBNZXQ/?tag=wranglerorg-20

Easy after watching multiple youtubes. Didn't bother with the find Top Dead Center etc... I did what many videos show and marked position on old cap/transferred marking to new cap and swapped. Used standard box wrench - no need for special tools.

Codes all cleared and haven't come back. Only been a few days so time will tell!
 

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