i think my crank sensor has gone out

i was putting along, happy as can be. and the engine suddenly cuts out on my 00 XJ. no gauges, all my other electrical stuff works just fine, no whine from the fuel pump, no gauges, but the engine turns over. all the symptoms of the the CPS going out. i havent tried unplugging it yet and seeing if my gauges come on yet.... i hope its not my CPS, i dread having to get in there to swap in a new one.

it's not that bad if you have a lot of extensions and a universal swivel. with about 3 feet of extensions put together you can get right up to the bolts from the side of the trans back by the tcase That's how i do it, if its being a real pain in the ass i'll put a jack under the tcase and take the crossmember bolts out, then lower it down until its almost hanging by itself but not quite. That usually frees up some extra hand room.

I'm not real familiar with the later XJs, but I doubt a bad CPS would affect the gauges.

cruiser54 said:

I'm not real familiar with the later XJs, but I doubt a bad CPS would affect the gauges.

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From what I have read a bad CPS can affect the gauges.

But swamprat, what you're describing sounds like the exact problem I was having earlier this year. I bought my jeep not running...threw a battery in her, and had no gauges, no power to the fuel pump, no spark, but it DID crank over. After some research I checked my grounds and traced my wires (there were mice in the jeep). Everything seemed fine so I bought a new CPS from Advance Auto Parts and swapped it out. This changed nothing. After tinkering for a few weeks and coming up with nothing I was getting rather annoyed, and decided to look for an ECU. A local kid had one so I bought it off of him, plugged it into my jeep and it fired right up without hesitation.

If your jeep needs a CPS, its not too bad. It is tight to get in there, but a little patients and a few F bombs later...you'll have her swapped out in no time.

Good luck! Write back when you figure out the issue.

I was able to change mine in a few minutes with a 1/4" ratchet and socket. When mine went, it also fried the computer, so if the cps doesn't solve the problem, check the pcm.

On the OBDII, if the crank sensor shorts to ground a few things will happen: the gauges will go blank, the engine won't start, and a code reader/scanner won't communitcate with the PCM.

Quick and dirty--unplug the crank sensor and if the gauges will then come back on, the crank sensor is shorted and must be replaced.

i cant find the plug for the crank sensor. i traced from the sensor and its under neither the jeep. but when i unplugged it my gauges still didnt work.

Swamprat said:

i cant find the plug for the crank sensor. i traced from the sensor and its under neither the jeep. but when i unplugged it my gauges still didnt work.

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Clarify, please.

You didn't unplug the crank sensor because you couldn't find the plug, but when you unplugged it the gauges still didn't work?

i found the sensor, traced the wires back to a plug, unplugged it and checked my gauges and still nothing. but the plug was under the jeep by the transmission. so i think i might have gotten mixxed up cause it looks like the plug for the crank sensor is under the hood on the fuel rail on just about every other XJ.

Yeah, I think you scored the wrong plug.

My Renix is up in the direction of the valve cover, scroll down the page to the CPS diagrams: http://www.lunghd.com/Tech_Articles/Engine/Basic_Sensors_Diagnostics.htm

I believe the late models move more toward the PCM on the driver's fenderwell.

00 and 01 CPS plugs are at or near the T-case.