CPS (Crankcase Position Sensor) - HELP!

Please Help!! - CPS (Crankcase Position Sensor)??

OK... so it's supposed to be located (the plug) behind the valve cover on the drivers side, but there's no plug there or in that area. However, on the passenger side, there is.

Here's how it happened:
I was driving down the road under normal conditions and my 2k Cherokee stalled. Had it towed home. Called a buddy he suggested the CPS and naxja,org. As I explained to him, It will turn-over, but not fire.

I've been reading several posts that the CPS (Crankcase Position Sensor), is a common issue with the XJs, so I was going to start there. Only I can't seem to be able to identify the correct plug.

If anyone has suggestions, I'm willing to listen. This is my first "real" issue with my Jeep - makes ignorant.

Please help!
regards,
rex

Find the TPS on the throttle body. Follow the wire until it enters the harness. There should be another connector coming out of the harness in the same area. The connector will either be round or oval. Follow that wire to see where it goes. If it leads down to about 1 o'clock on the bellhousing, that is the connector for the CPS.

-edit- Oh, and it's the crankSHAFT position sensor.

welcome to the jeep world:

J ust
E mpty
E very
P ocket


good luck, i also had trouble starting my jeep and had problems with it not starting at the same time, and if it did start, then idle was real rough and didnt accelerate correctly.... anyway it was the throttle position sensor... (TPS)

best of luck...

The plug itself is not quite behind the valve cover. It's more like to the driver's side of the rear portion of the cover.

The CPS itself is at about the 1 o'clock position on the flywheel housing, as you stand at front of engine bay and look back. It's kind of tucked down there, so you'll barely be able to see it from above, but it's right near the joint between engine and bell housing, attached to the bell housing by two bolts from behind. You should be able to spot it, and follow the wires back up to the connector.

Actually removing it is done from below, using long extensions and a u-joint on a 1/4 or 3/8 inch drive ratchet. I found a couple of long extensions, one medium, and one u-joint on a quarter-inch ratchet worked, with different placements of the joint for the two bolts. The bolt heads are 11 millimeter. Replacement is a little tricky, but I found with the 93 that I could just reach in from above enough to set the bolts in their holes, then go below with the ratchet and tighten them.

Does a 2k model still have user-accessible fault codes? A failed CPS should set a code. It's a very likely suspect for a sudden no-start condition, but not the only one, so it might be worthwhile seeing if you can retrieve a code before spending too much.

WoW!! thnx for the quick replies!!

by "user-accessible fault codes", i have to assume that this is something i would need a code reader for?

looks like i'll be tracing some wires... thnx for the help!

rex

Your 2000 XJ is OBD-II (as in On Board Diagnostics, 2nd generation) compliant. That means just about any licensed repair facility should have a scanner that will at least read the codes, and you can but one at any auto parts store. Auto Zone and Advance will read the codes for you for free -- but you have to have the vehicle at the store, so that won't help you this time.

I was looking at an OBDII code reader at AA the other nite for ~$150 or so as one of those 'nice to have' things that when you need it you need it NOW.

would this work to read the codes:
http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=46030 ???

and let's assume i can read the codes... where can i find out what code means what?

rex

OK. so i found the sensor... the wires from it go down to a connector that traces back over top the tranny and up to another connector on the passenger side.. about the level of the bottom of the valve cover. the other wires from the connector go to the O2 sensors...

i DID have the "check engine" light on for a month or so, but it would go out from time to time and autozone read the code and told me that it was an O2 sensor, but didn't know which one of the two.

i was putting it off until i changed the oil again.

could the O2 sensors (gone bad) cause the engine not to fire?

rex

I really hope someone answers this question better then I can.
I think that the O2 sensors themselves won't prevent the engine from starting. Now, the wires are another thing. They're close to the ASD Relay and go through the C107 connector.... along with Grounds and +12Volts. A bad connection and/or a short could potentially cause the sensor to give a bad reading or interfere with other circuits.... and the Ignition and fuel pump work out of the ASD too...
My 2001 has similar problems and, after checking almost everything, I'm suspecting this. If only I could get some decent, standard OBD2, codes out of the computer (Venezuelan market), maybe I'd've gotten to this point sooner.

yea, i've bought a code reader and then rented a scanner from autozone... and still no codes.

it's headin to the garage. i don't have time or money to start replacing sensors.

goos luck to you!

rex

Pulled the O2 1/1 sensor last night. Sure enough: it had been impacted by the end, where the wires are (I bought a used car) and nucely covered with tape. The wires had been intermittently shorting and causing injector and ignition shutdown.
The dealer is checking now to see whether they have the new O2s in the country...... I'd ordered it before, but they got the O2 1/2.
BTW. A discovery that I made with the 2001 (probably the same in the 2k) is that the jeep limps home even when the CMP (Camshaft sensor) is 180* off. It took a while to realize why it wouln't come out of limp mode.

I talked the mechanic today... great guy. he suggested that i check for spark before i start replacing parts.

anyone know how to check for spark on 2k jeep cherokee?? i'm totally new at the coil pack... with no plug wires how do you do this?

rex

Well, after having to "special order" a CPS from autozone, becuase no dealer, no parts store, and no garage in town had one, it ended-up costing me ~$98 (tax and $8 to next day it).

I just wanted to thank everyone here for their input.

rex