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4.0 Crankshaft Position Sensor Replacement

06-15-2006, 09:05 PM
Since the longevity of the CPS is an issue on the 4.0 - and since it's likely to stay that way - I thought I'd post my experience in replacing the CPS on my 2000. If anyone else has any tips or observations, your input will be appreciated.

I had the classic symptoms: occasional rough running, died on the highway (more than once), started right back up, occasional odd shifting pattern. Oh yeah, and the P0320 code was a dead giveaway. :icon16: I'll try to borrow a good digital camera and get some pics to post up later. Anyway:

(For the cliff notes, move down)

Time: about 2:30
Beers: 3
Cuss words: forget
Cuss words directed at engineers: about 5
Tools: flashlight, 10 mm socket, 7/16" socket, 2' of extensions (2x6" and 1 12"), swivel, and blade screwdriver (and of course 3/8" driver)

So starting out, the toughest thing was to spot where I'd be working. From posts here, I knew that the sensor was on the bell housing at the 11 o'clock position when viewed from the driver's seat. Even though it was bright and sunny out, damned if I could find it. Beer #1 while I got the flashlight and took a good look. A-ha moment, spotted the wiring harness going towards the sensor first. (D-C said it was hooked from just behind the intake manifold, but mine came from the opposite, passenger, side of the engine, down below the valve cover a bit).

Followed the cable over, and almost out of sight spotted the sensor's location. Didn't look right though, until I took a look from the bottom. There, I spotted it - again, almost out of sight, right where it was supposed to be. From below, I could see there was some sort of bracket, or shield, that I'll call the widget. It looked like it was there to guide the wires around to the opposite side of the engine. Found a good spot to put the 4-cell flashlight, front end wedged between the front driveshaft and the body, the tail resting on the transmission mount....almost perfect alignment to see the sensor from below. Once you're underneath you'll see the positioning works.

So, plan of action. From looking at it, would need to remove the single bolt from below, but couldn't reach my hand up in there no matter how I worked it. So would have to put bolt back from above. Removed the air intake with the 10mm and screwdriver from where it attached to the throttle body in order to have a clear shot from above. Now could easily visualize the sensor from under the hood, though it was very tight between the fuel rail and the firewall.

Crawled under, got the extensions hooked up and although it was fairly easy to get to the bolt, watch the fuel line that runs right next to it - it'll be in the way for most of the job but you can work around it. Bolt came out no problem. (Plan to drop the bolt/widget combination.) You'll want the swivel just before the socket. The bolt on mine was 7/16".

Up above, detached the electrical connections. Again a tight fit for the hands, but manageable with a little help from Mr. Screwdriver. It was about here that I stopped cursing the engineers for the tight fit, since it was obvious that if the engine was out of the vehicle (like, at the factory) this would be less than a 5 minute job. There's also one of those plastic pressed clips supporting/holding the sensor leads onto the wiring harness which had to be detached.

At first I thought it would be a pain to thread the wires behind the back end of the block, but you can easily pass them over and behind/above the back of the valve cover. Start from the driver side and work your way over. I figured this out while removing the old sensor.

OK, beer #2. Removing the sensor was easy, just had to wedge my hand in there and work it out. It sticks pretty far into the bell housing. NOTE: I'm 6'4" and had a tough time reaching all the way back there from the front, until I got something set up in front of the Jeep to stand on. Then I could reach and I was almost laying on the engine to make it there. Some might have better luck from the side. I ended up using my left hand while standing on right foot.

Putting the new sensor in wasn't tough(it actually sticks pretty far in), and neither was snaking the wiring around the back side of the engine to reach the connection to the wiring harness. Pushed the sensor in most of the way.

Now, had to get the bolt in. With the widget, tried several times, both from above and below, to get the combo put back in. Tried widget by itself and with the bolt inserted. No luck. Remember I said to plan to drop the widget/bolt combination? Well, I followed the plan - 3 times. Keep in mind that the gray bolt is exactly the same color as the rocks in most driveways, and that there's a perfect space for them to fall onto - on top of the left front corner of the transmission, and you'll probably save some time when you drop them. :angryfire

Anyway, after searching for dropped parts, twice, and starting beer #3, finally decided to not reinstall the widget. The sensor is in a protected place, so figured it would be ok. Once the widget was out of the plan, easy enough to get the mounting bolt back in. Held it between index and middle finger and got it in. Tried both from top and bottom (from bottom with socket); suggest from top unless you have some sort of special socket to hang onto it while you get it in. D-C's directions say to finger tighten, push the sensor in against the flywheel, then tighten up. Easy enough.

Crawled underneath, put the socket to the bolt and tightened well. The directions say 7N-m, or 60 in.lbs.....I figured good and tight but not too tight would be the correct amount. (Also compared tightening torque to what I'd used to remove it and made it about the same)

Compared to fighting with the widget, hooking up the electrical connections was child's play. Made sure all connections were made, including the clip.

One final check for tools under the hood, made sure my hand was (mostly) non grimed, reached in and turned it over. (Please run) Chir-chir-chir la la la la la....


So after that, cleaned up, showered, opened beer #4. Job done. Wait, one more thing: post up to AF to help out!

Cliff notes:

Remove intake from throttle body.
Use flashlight to visualize from above & below, 11 o'clock from driver's perspective.
Need extensions to reach bolt, remove from below.
Electrical connections may not be where specified in instructions.
Long reach to sensor from above, need something to stand on.
Reaching to sensor with hand blocked from below.
Installing with widget a pain.

Hopefully this will help out for everyone that's going to be doing this repair. Questions welcome.

06-16-2006, 10:26 PM
Mine is a 1996, but I also noticed some sort of "hood" or cover that was routing the wires to the passerger side. Can you "pop" this widget off or does it come off when you remove the bolt?

I have the metal arc looking bracket type CPS. Is that what you have or is it a single bolt small black type??


06-17-2006, 08:21 AM
Mine is a 1996, but I also noticed some sort of "hood" or cover that was routing the wires to the passerger side. Can you "pop" this widget off or does it come off when you remove the bolt?

I have the metal arc looking bracket type CPS. Is that what you have or is it a single bolt small black type??


I have the black cylinder one, held on by one bolt. The widget was held on with the same mounting bolt as the sensor.

08-03-2006, 01:39 AM
Time: about 2:30
Beers: 3
Cuss words: forget
Cuss words directed at engineers: about 5
Tools: flashlight, 10 mm socket, 7/16" socket, 2' of extensions (2x6" and 1 12"), swivel, and blade screwdriver (and of course 3/8" driver)
Hopefully this will help out for everyone that's going to be doing this repair. Questions welcome.
Hi, total noob here, just found the forum after Googling and finding your post.

My entire family was riding in my 1999 Jeep Grand Cherokee Laredo 6cyl at about 30mph when it cut off. My son, who uses it almost exclusively, said it had been doing it lately. The engine quits, then restarts by itself after a couple of (very long) seconds. Did it at around 30 mph, will even do it while accelerating.

We took it to the dealer who thought it was the battery terminal connections, and he also cleaned the throttle body.

It did not solve the problem. I'm a little energized on the subject, because an old Wrangler did the same thing to my son and caused him to total it. He wasn't hurt, but he obviously could have been.

So we took it back to the dealer, and they said they THINK it was the CPS. Changed it to the tune of $110 for the CPS, and $348 for labor. The labor seemed quite high to me--I interpret that to be four hours or more.

Since I am not talented in auto repair, I was hoping someone could advise me as to whether or not I was ripped off. I plan to wait a week or two before deciding if the problem is fixed, since it was intermittent.

Don't get me wrong--my son's safety is more important to me than a couple of bucks. I'd just like some input on whether this is a reasonable labor charge. I'm also wondering how much of that is "diagnosis."

Thanks for any help you can provide.

08-03-2006, 07:50 AM
I'm not sure where the location is for the CPS on a 99, but mine is in a VERY tough place to get to on the transmission bellhousing and it only took an hour for them to do mine @ 66.00 labor. The ripped you on the labor I think.

The part could have been 110.00 if it was MOPAR, my '96 was 92.00 at the dealer.

That problem sounds like the CPS. The first time I changed mine it was shutting off and then would restart after a period of time. That is a typical symptom of one going bad and it doesn;t always throw a "Check Engine" light right away either.

I think you got the right part, but they milked the labor $$$


08-05-2006, 07:54 AM
Sounds high on the labor. The "book time" is usually a lot lower than my "first time ever repair" time. :) Seriously though, I'd head back to the shop, ask to see the labor recommendation for the time for the repair. There should be a time listed, in hours.

08-10-2006, 10:41 PM
Hey guys,

My 95 JGC Orvis 5.2L (188K miles) is stalling out but not at regular speeds. It generally stalls if I give it gas to take off then let off, like you would in stop-n-go traffic. It is really evident if I go in reverse out of a parking space for example then let off to put it into drive. If I throw it into Nuetral quick enough, it won't stall.

I've replaced the IAC (Intake Air Control) Valve but did not see all the warnings to disconnect the battery before doing so.:banghead:

So, a few questions.
1 - Did I blow the IAC? Should I replace again?
2 - Will dis-connecting/reconencting the battery at this point help?
3 - I've seen comments about the CPS being the culprit but your symptoms are slightly different than mine. Should I give it a try?
4 - Do you know if the location on my 95 is the same as yours?

Thanks in advance for all the help,

08-29-2006, 05:37 PM
We are having the same stalling issues as many of you, stalls when we come to a stop sign/light. What the heck. We have it at Firestone right now - second day and yesterday they said they didn't know what it was because they drove it and it didn't die - still hasn't died but they are suggesting new CPS - I think my husband is going to get the JGC out of the shop today - they said they wouldn't charge for the diag yesterday but today they have changed their minds, another downside of not owning one of these gadgets myself. Anyhow - ours is a 1995, we have already replaced the sparks, wires, coil and fuel pump - I hope this works. I will let you all know. We are new to this site and love it - I am so thankful for the web.

PS - do any of you know the part number for the CPS and the TPS? Any other ideas of what to do would be appreciated.

**UPDATE**Firestone is a joke - they said that they wouldn't charge for the diagnostic but to "never come back to his shop" no prob dude.

08-29-2006, 08:57 PM
Alrighty folks, here's the latest in this saga.

Jeep was in the shop for about a week where they tested out a bunch of things but couldn't definitively identify the problem. He is having a hard time accepting the idea that it might be the CPS. He insists that it should start if it was.

They did a MotorvVac, replaced a broken engine mount and some exhaust work. These are all things that needed to be done but that could sort of compound the stalling problem, supposedly. I had already replaced the IAC and TPS about 1 week prior.

Well, it did change how the stalling happens. Now, it doesn't really stall on take off anymore but it does stall when at a stop. Basically the reverse of what was happening prior to the repairs.

I have a slight slipping in the transmission which he confirmed so I was wondering, is there any chance that maybe the tranny is not disenganing in 1st gear fast enough and causing or at least contributing the the stalling?

If I could find the CPS, I'd replace it myself but I spent 1/2 looking for it at 11:00 O'clock on the bell housing but can't find it. Anyone got pictures?

I may tell him to replace the CPS regardless of whether he thinks its the issue or not just to settle my curiosity. I know that it is approx a $100 gamble but I'm thinking it might be worth the gamble vs the alternative which is dump the vehicle for a crappy trade-in value. It is worth A LOT more to me than what they'll offer in trade. :disappoin

So, do I have him do the CPS regardless if I can't find the damn thing myself?


08-30-2006, 10:02 AM
Update - my husband purchased both the TBS and the CPS, he put the TBS in and thinks it solved the problem. I just pray it stays solved, I told him about all I had read on line about fixing it and then it comes back so we will just have to wait and see what happens. He returned the CPS but I have a feeling he will be going to buy it back before the weekend hits. Thanks for all the info...:loser:

09-02-2006, 10:08 PM
Alright mr fredjacksonsan, I have just read your detailed how to on replacing crankshaft position sensor very closely as i am about to attempt to replace the one on my wife`s 98 grand cherokee 4.0/auto. It seems as if you have left out a very important step, as i laid in the mud puddle this morning getting rained on; Ernesto. I noticed on my vehicle in the way of getting to the sensor was a cable leading to either transmission/ transfer case from under the body; looped directly in front of sensor. This will make a tough job even tougher for me; am i the only one with this cable in the way. Does anyone know how to disconnect; could not tell. Jeep will not start; no fire. When i turn ignition switch to run get check engine light ; then it goes out like normal. Could this be crank position sensor or not. Replaced ignition coil; spark plugs and wires; cap and rotor; 80,000 miles on all components ;tune up needed anyway. Should I replace camshaft position sensor. read other thread that said vehicle would start even if this is bad.

09-03-2006, 08:00 PM
Few things i noticed while doing my 99 4.0 crank sensor yesterday.
that wedgit thing, i used a small wire tie to secure it in place on the sensor before putting the sensor into the bell housing (thought of it after 30 minutes of cursing). Made it a little easier to reinstall the bolt.
Don't connect the sensor wire until the sensor is bolted in b/c the sensor mounting lug rotates out of position and you don't have leverage to move it into position while inserting the bolt.(again 20 minutes of cursing)
And that plastic tubed cable right in front of the CPS bolt can be moved slightly if the clip holding it to the metal tube is removed allowing a little better access to the bolt.
Not a job i want to do again anytime soon. My condolences to whoever has to replace the sensor.

09-03-2006, 08:34 PM
Thank you for the info mikec041 that sounds helpful for us poor souls that are looking at replacing.First day off this week that is not raining I will be replacing mine. My plastic cable appeared to need to be removed on one end which I did not want to do. My cable is covered in some type of heat shield/insulation but I did not see it attached to anything else; this metal tube you are referring to but will look in the morning time permitting. Again thank you and all that make this board available to us in need; after doing job will post my experience as well in hopes it may help the next.

09-16-2012, 01:21 PM
Just finished replacing the CPS and found that assembling the "widget" (a.k.a shield 56041388AA) was the true PITA. Used a telescoping magnet to hold in place, and then installed bolt (with electrical tape on inside of socket to hold in place). I had tried 3 different tack materials to hold the shield to the bolt washer prior to installing and all methods failed.

10-03-2012, 11:09 AM
Thank you for The info mikec041

11-09-2013, 04:23 PM
Has anyone tried unbolting the driver's side engine mount and lowering the engine for better access?

10-18-2015, 08:22 PM
The CPS was faulty on our 1996 Jeep Grand Cherokee causing severe missing for a long time and finally ocassional stalling. The missing was most severe and the OBD diagnostic tool only pointed up cylinder misfires. However the lightbulb went on in my head when I associated another OBD failure; fuel trim = -100%. This indicated the computer was shutting off the gas due to lack of CPS pulse. Installation of an aftermarket CPS solved all issues.

I had dealers in Rio Rancho, NM state that they had seen the problem before on 4.0 Jeep and couldn't fix it . . . hmmm.

10-31-2015, 02:52 PM
BTW the new CPS also fixed the rough idle in the AM. No longer need warm up jeep for 10 minutes in cold weather.

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