Need help with P0391 code

Clarythedrill

Member
Joined
Jul 2, 2019
Messages
89
Location
Ft. Worth, Texas
To all, this weekend I changed the timing gears and chain, water pump, radiator, reservoir, coolant, and hoses on my 2001 TJ with the 4.0.

Everything went really smooth and got it back together no problems, and it runs absolutely wonderful when I drove it today (I let it set for a few days so the RTV and everything would set up correctly). BUT, I got a check engine light and the code is 1391, camshaft positioning sensor. I know for sure I had the timing marks lined up perfectly before removing the old chain and gears and putting the new ones one. I have not ever had that code before, only after changing the timing gears and chain. I did set the alternator and bracket against it when I removed them to get to the timing chain cover, but that should not have moved it or anything.

I am prepared to get a new sensor, but thought I would ask for some input from the board before doing so. Again, I am certain I put the new gears and chain on correctly and the timing marks lined up perfectly. The old chain was so loose it could almost come off without removing the gears, and the new one was extremely tight going on.

So, any thought before I put a new sensor on? Thank you for any input, it is appreciated.
 
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Who is the manufacturer of the new CKPS that you installed ?
IF it is not the Mopar OEM part; then there is a good chance that is your problem.
Since purchasing my '01 Sport 4.0L in January due to the decrease in availability of the Mopar OEM parts; I have purchased a spare for the CKPS, CPS, IAC, MAP, TPS, Oil Pressure and Water Temperature sensors.
Still need to get a IAT sensor.
 
What is the CKPS? The timing chain and gears are Duralast brand, from Autozone. I changed no sensors at all when doing the above work. I only set the alternator and bracket against the cam sensor when I removed it to get to the timing cover.
 
I'd reset the codes and see what happens first. If that doesn't work I think the best thing is to find somebody with the real Chrysler tools and do a re-learn for the system. You can use any sensor brand you want but you have to follow the correct procedure in the factory service manual to re-sync everything. Unfortunately it requires expensive equipment to do that properly.
 
Pagrey, thanks for the input. Today it started shuttering at idle and showed a low of power, so something is definitely amiss with it. I am thinking I will replace the sensor and the piece that goes into the block and see what happens. I dont mind spending money on it, since it is old and I dont know what the previous owner ever did to it.
 
What is the CKPS? The timing chain and gears are Duralast brand, from Autozone. I changed no sensors at all when doing the above work. I only set the alternator and bracket against the cam sensor when I removed it to get to the timing cover.

My apologies.... I had not drank my first cup of coffee when I read your post...
Thought you said you replaced the CKPS (Crank Position Sensor) with an aftermarket knock off.
The link below will walk you thru the installation of a Camshaft Position Sensor and the alignment procedure.

Replace CPS by Golen Technician
 
Charles, thank you for the video. I am beginning to think that when I put the alternator and bracket against it, it may have turned and put it out of place enough to throw a code. I have noticed that a lot of nuts and bolts are loose on the engine, so I will check that. Hell, when I got to the timing cover, all the bolts holding it on were only finger tight. I think I will change this out on my next day off. Thank you again for the input and the video.