Just got replacement PCM - Page 4 - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Grand Cherokee & Commander Forums > ZJ Grand Cherokee Forum > Just got replacement PCM

15 x 8 Black D-Window Steel Wheels Set of 4Magnaflow SS Cat Back Exhaust System, Street, High ClearanRCV Heavy Duty Axle Shafts Now Shipping at Baseline4x4.com

Reply
Unread 07-13-2013, 05:20 PM   #46
reynoldsjp
Registered User
1998 ZJ 
 
Join Date: May 2013
Location: roanoke, va
Posts: 31
I did the CPS test today with a meter and got nothing wrong. Is there any one of these that would cause the others ? I have switched the relays a long time ago never had issue with them. So I am leaning to the IAT.

reynoldsjp is offline   Reply With Quote
Unread 07-13-2013, 05:43 PM   #47
ZeeJay1997
Registered User
1997 ZJ 
 
Join Date: Dec 2008
Location: Sweet Home, Alabama
Posts: 6,173
Quote:
Originally Posted by Uniblurb View Post
I'm probably somewhat guilty of of pushing the crank sensor as the stall/no-start problems
No Uni, you try to get them to check it first and suggest they perform routine maintenance. Some people do drive-bys and throw in the "crank sensor " bomb on every stalling thread.
ZeeJay1997 is offline   Reply With Quote
Unread 07-13-2013, 05:43 PM   #48
dusterdude
Registered User
1996 ZJ 
 
Join Date: Jan 2012
Location: hopewell, va
Posts: 2,041
Mine didnt check bad either but when i got it off it had a weak magnet
dusterdude is offline   Reply With Quote
Unread 07-13-2013, 05:43 PM   #49
Oldfrog
Web Wheeler
1997 ZJ 
 
Join Date: Feb 2008
Location: Louisiana/Texas
Posts: 3,589
Did you test for the 5v source at the crank sensor plug? ( key on)
__________________
Cajun Recipes and Fishing tips

Words of wisdom, Posted by Zeejay:
"..it's not air, it is the opposite of air... suckage so to speak."

Stalling? Work through Zeejay's list
Oldfrog is offline   Reply With Quote
Unread 07-13-2013, 05:47 PM   #50
ZeeJay1997
Registered User
1997 ZJ 
 
Join Date: Dec 2008
Location: Sweet Home, Alabama
Posts: 6,173
Quote:
Originally Posted by reynoldsjp View Post
I did the CPS test today with a meter and got nothing wrong. Is there any one of these that would cause the others ? I have switched the relays a long time ago never had issue with them. So I am leaning to the IAT.
There are some tests for the IAT you can do, or if you're so incline, buy a new one and try it.

As discussed earlier in the thread, a missing crank sensor signal will cause the PCM to pull the ground for the ASD relay.
ZeeJay1997 is offline   Reply With Quote
Unread 07-13-2013, 06:54 PM   #51
reynoldsjp
Registered User
1998 ZJ 
 
Join Date: May 2013
Location: roanoke, va
Posts: 31
Ok so I went back to the Jeep and moved relays around testing each in the horn. They all were good. I had someone turn the key while I held my finger on ASD and the Fuel Pump relays. Both clicked after key turn. The check engine light is now off. This whole thing has really gotten me. I am used to a problem happens and the car doesn't work until it's fixed. Not problem happens and car works sometimes and not others. I tried to the best of my ability to check the CPS with procedure given earlier in this thread. I am thinking that this sensor is probably bad. I have been putting it off replacing due to location. I guess it's time to bite the bullet and just do it. I have found one online that is Mopar OEM. So I am going to work towards getting this Jeep home and then new CPS. What ever is wrong wasn't there at all during the hour test drive I took when buying. It started as hiccups at high speeds then became more frequent turning to random stall. I have limited funds so I will do what I can when I can and post updates. Thanks to all for now.
reynoldsjp is offline   Reply With Quote
Unread 07-13-2013, 09:31 PM   #52
dellis
Registered User
1998 ZJ 
 
Join Date: Feb 2013
Location: Vienna, VA
Posts: 313
Before replacing it, just make sure that you indeed have 5 volts being supplied to it (during a stall or no-start condition).
dellis is offline   Reply With Quote
Unread 07-14-2013, 12:35 PM   #53
reynoldsjp
Registered User
1998 ZJ 
 
Join Date: May 2013
Location: roanoke, va
Posts: 31
Weirdness continues. Left it sitting overnight. Went back today and started right up. Drove it home. I am walking away from it for a few days. Seems that it happens after it gets warm and if left sitting long enough will start right up. Now that it is home I went back out to restart it and it wont start. Im done.

Last edited by reynoldsjp; 07-14-2013 at 01:02 PM..
reynoldsjp is offline   Reply With Quote
Unread 07-14-2013, 02:32 PM   #54
Oldfrog
Web Wheeler
1997 ZJ 
 
Join Date: Feb 2008
Location: Louisiana/Texas
Posts: 3,589
I will assume the 98 wiring colors are the same as 97....so check before you rely upon my wiring colors:

Ok...try to start it again. If it doesnt start, do this:
Disconnect the TPS connector, turn the key to "ON" ( not "start") ....and test for +5 VDC coming from the PCM at the harness side of the connector.

If it's low...leave the TPS disconnected and begin performing the same test on the CPS connector, MAP , and Cam sensor connector....leaving them disconnected, one by one. If one of them is pulling it to ground, disconnecting it should allow it to reach 5 V again.

The 5 V feed wire should be wht/blk,....**** IF it's the same color as a 97.***

If you still do not have 5 Volts after disconnecting them all....then you move to visually inspecting the wire as it travels from sensor to sensor and/or making sure that your grounds are good.

If you STILL dont have 5volts on that circuit, then move to the voi/wht wire on the back of the transfer case ( speed sensor) then the gov pressure solenoid in the tranny.

Either way you want to go about it is fine, but you will need that 5 Volts. If it's down, something is causing it to go down....either a bad sensor, a high resistance short to ground, or a bad 5 V power supply in the PCM.....or even "bad" or intermittent 12v going TO the PCM....or ground.
__________________
Cajun Recipes and Fishing tips

Words of wisdom, Posted by Zeejay:
"..it's not air, it is the opposite of air... suckage so to speak."

Stalling? Work through Zeejay's list
Oldfrog is offline   Reply With Quote
Unread 07-14-2013, 07:41 PM   #55
dellis
Registered User
1998 ZJ 
 
Join Date: Feb 2013
Location: Vienna, VA
Posts: 313
Quote:
Originally Posted by Oldfrog View Post
Either way you want to go about it is fine, but you will need that 5 Volts. If it's down, something is causing it to go down....either a bad sensor, a high resistance short to ground, or a bad 5 V power supply in the PCM.....or even "bad" or intermittent 12v going TO the PCM....or ground.
I don't think he's ever said that his 5V reference is bad.
dellis is offline   Reply With Quote
Unread 07-15-2013, 12:16 AM   #56
Uniblurb
Web Wheeler
 
Uniblurb's Avatar
1996 ZJ 
 
Join Date: Jan 2012
Location: Central, Ohio
Posts: 3,213
Quote:
Originally Posted by ZeeJay1997 View Post
No Uni, you try to get them to check it first and suggest they perform routine maintenance. Some people do drive-bys and throw in the "crank sensor " bomb on every stalling thread.
Yeah Zee, used to throw parts at mine before learning diagnosis and preventative maintenance will save you a lot of $/grief in the long. While I've had particularly bad luck with 4 faulty cranks sensors I still try to keep an open mind since the electronics on these ZJ's is about predictable as the weather.


Quote:
Originally Posted by reynoldsjp View Post
Ok so I went back to the Jeep and moved relays around testing each in the horn. They all were good. I had someone turn the key while I held my finger on ASD and the Fuel Pump relays. Both clicked after key turn. The check engine light is now off. This whole thing has really gotten me. I am used to a problem happens and the car doesn't work until it's fixed. Not problem happens and car works sometimes and not others. I tried to the best of my ability to check the CPS with procedure given earlier in this thread. I am thinking that this sensor is probably bad. I have been putting it off replacing due to location. I guess it's time to bite the bullet and just do it. I have found one online that is Mopar OEM. So I am going to work towards getting this Jeep home and then new CPS. What ever is wrong wasn't there at all during the hour test drive I took when buying. It started as hiccups at high speeds then became more frequent turning to random stall. I have limited funds so I will do what I can when I can and post updates. Thanks to all for now.
Once in testing one of my Mopar crank sensors it tested fine from the passenger side but real pain to reach back that far. Then after fishing the connector out it tested bad from the drivers side! Really threw me for a loop and here the wires were broken/shorted internally right at the sensor itself. Don't know why I keep installing that metal heat shield on the sensor bolt since it causes the wires to bend at such a severe angle!

Not saying this is what was happened when your CKP tested OK but just thought I'd mention it. Hang in there, I was in the same boat, and good luck!
__________________
96 4.0 ZJ Laredo, 2004 4.7L WJ Limited, 93 4.0 XJ (spare), 96 4.0 XJ (son's)

-Stalling ZJ? 12 things to check before replacing a sensor; the Dirty Dozen
-Crankshaft position sensor multimeter test. & video of testing.
Uniblurb is offline   Reply With Quote
Unread 07-15-2013, 08:24 AM   #57
dellis
Registered User
1998 ZJ 
 
Join Date: Feb 2013
Location: Vienna, VA
Posts: 313
Quote:
Originally Posted by ZeeJay1997 View Post
No Uni, you try to get them to check it first and suggest they perform routine maintenance. Some people do drive-bys and throw in the "crank sensor " bomb on every stalling thread.
I've noticed that as well, and (of course) when the Jeeper follows the crank sensor advice and it doesn't work, then it causes them to be leery of other, more responsible, members who are giving direction.

Perhaps it is important for many of us to affirm posts in threads that are actually doling out responsible advice.
dellis is offline   Reply With Quote
Unread 07-15-2013, 12:54 PM   #58
Oldfrog
Web Wheeler
1997 ZJ 
 
Join Date: Feb 2008
Location: Louisiana/Texas
Posts: 3,589
Good advice. You can be $800 deep into buying sensors and stuff before you know it and nothing has changed.
__________________
Cajun Recipes and Fishing tips

Words of wisdom, Posted by Zeejay:
"..it's not air, it is the opposite of air... suckage so to speak."

Stalling? Work through Zeejay's list
Oldfrog is offline   Reply With Quote




Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.