There are several reason why you would need to replace your Jeep TJ Wrangler's Crankshaft Position Sensor (or CPS for short) with the most obvious one being that your 'check engine' light has illuminated and a quick check with an OBDII reader indicates you have thrown one of the following MIL codes.
Crankshaft position sensor at about 11 o'clock on the bell housing. Easiest way to verify is to crank the enine and watch the tachometer, if it doesn't bounce while cranking, it's the CPS.
For me, my Jeep wasn't throwing any codes and so I wasn't completely sure that this was something I needed to replace. What lead me to think that it may need to go was the fact that I now have over 120,000 miles on the odometer, I have already replaced my O2 sensors and still had various engine issues including a rough idle under specific conditions. Specifically, my engine would run very rough on cold mornings or after driving it a long time with the AC on, turning off the engine briefly and then starting it back up again. I had also experienced times when climbing up long highway hills the engine would run quite rough... almost as if it were misfiring. Now, I should tell you that things are better since installing a new CPS but my engine is still running far from perfect.Anyway, this write-up should help you out if replacing your Crankshaft Position Sensor is something that you need to do.Instructions
Your Jeep TJ Wrangler's CPS is located on top of your transmission's bell housing as can be seen in this photo which was taken standing on the driver side of my Jeep and looking down into the engine compartment.
1. The bolt or bolts (different years have the CPS secured to the bell housing in various configurations) can be access either from the engine compartment or from underneath your Jeep as shown in this photo. Using a 7/16" wrench or socket with 3" drive extension, remove the bolts securing the CPS in place and pull it out of the bell housing.
2. The wiring harness for your Jeep's CPS wraps around the engine block and it's plug can be found on the passenger side it, behind the oil filter and next to the fire wall as shown it this photo.
3. The CPS wiring harness plug may be a bit difficult to unplug and if needed, a small flat head screwdriver can help. Just be careful not to use too much force as you will break the plastic plug. Once unplugged, remove the CPS out of your engine compartment.
4. Insert the new CPS into your Jeep's bell housing and secure it in place to 60in. lbs. of torque using the factory bolt(s) and a 7/16" wrench. Then, pass the wiring harness around the back of the engine block so that the plug is on the passenger side of your Jeep.
5. Plug in your new CPS wiring harness making sure that it clicks into place.
That's it, you're done! The entire job should take minutes to do. Please email
me with any questions you might have.