Ok guys and gals, I have a 1999 Cherokee 4.0 auto that is throwing the code P0340 "Camshaft position sensor A circuit bank 1 or single sensor" and P1391 which I don't know what the heck that is!!!!!!!! My understanding is there is not a cam shaft sensor on the year because it has a distributor???? Not sure where to start on this one. Any help?? I forgot to mention the jeep runs fine. So far no problems what so ever.

 

The Camshaft Position Sensor is inside your distributor. If you pull the distributor cap off you'll see a black disc under the rotor with a set of wires coming out through the side of the distributor - this is the cam sensor.

Check the wires coming out of the distributor for bare spots and detach the connector and clean both sides out with CRC Electronic Cleaner.

P0340 and P1391 (loss of cam or crank sensor signal at the PCM) usually go together.

Clear the codes by disconnecting the batt negative cable for about five minutes, or use a code reader to clear the codes, wiggle the wiring harnesses, crank it up and see if the codes return.

You may have a bad cam sensor (Switch Plate as Chrysler calls it) in the long run.

 

Thanks CCKen. Your always a big help. I'll check it out!!!!

 

...and this 12-year-old post helped me to figure out what a CPS looks like on my 1999 Cherokee (parts places call it a pickup coil).
Instead of cleaning, I spent the money to replace it and the rotor while I was at it. Running normal now.