The Last Straw - Page 3 - 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 Cherokee & Comanche Forums > XJ Cherokee Technical Forum > The Last Straw

Stainless Steel Door Hinge PinsPoly Door Hinge BushingsFS: 2007-2013 Jeep Wrangler "HALO" Angel Eye Kit

Reply
Unread 03-17-2014, 09:29 AM   #31
CCKen
Web Wheeler
 
CCKen's Avatar
1999 XJ Cherokee 
 
Join Date: Jul 2011
Location: Canton, MI
Posts: 1,890
Study the attached diagrams.

Try this:

Temporarily disconnect the battery negative post connector.

Disconnect PCM connector C3 (Gray).

Reconnect the battery.

Turn the Key to RUN.

Does the fuel pump run continuously?

If yes, the fuel pump relay control coil ground wire is shorted to ground in the harness between the PCM and the fuel pump relay.

If no, a circuit in the PCM C3 connector is probably supplying the ground(s).

Note in the C3 pinout that C3, pin cavity 19, fuel pump control, and pin cavity 20, evap purge solenoid control are next to each other. And note that pin cavs 1 thru 5 and 8 thru 10 are also all control circuits (ground circuits).

Answer the above questions and get back. Based on your answers you may want to use an Ohmmeter to test the circuits for shorts to ground.







__________________
If we have data, letís look at data. If all we have are opinions, letís go with mine.

Man who stands in front of Jeep gets tired. Man who stands behind Jeep gets exhausted.

Last edited by CCKen; 03-18-2014 at 08:42 AM.. Reason: Deleted reference to Evap Solenoid cliking when C3 is disconnected
CCKen is offline   Reply With Quote
Unread 03-17-2014, 10:07 PM   #32
who_datjeep
Registered User
2001 XJ Cherokee 
 
Join Date: Sep 2012
Location: Houston, TX
Posts: 221
Hey CCKen. That is awesome information. I haven't been able to work on the Cherokee lately because I have been very busy. I will use this and get back with the results.

Thanks,
Kevin
who_datjeep is offline   Reply With Quote
Unread 03-18-2014, 08:49 AM   #33
CCKen
Web Wheeler
 
CCKen's Avatar
1999 XJ Cherokee 
 
Join Date: Jul 2011
Location: Canton, MI
Posts: 1,890
Quote:
Originally Posted by who_datjeep View Post
Hey CCKen. That is awesome information. I haven't been able to work on the Cherokee lately because I have been very busy. I will use this and get back with the results.

Thanks,
Kevin
I edited my previous post to delete reference to the Evap Purge Solenoid clicking with C3 diconnected. The solenoid will not click when C3 is disconnected because the PCM pulses the solenoid with a ground driver to make it cycle.

~~~~~~~~

See if you can line up a replacement PCM (same part number as the one on the side of your current PCM) just in case...

If you do get a replacement, make sure it's not programmed for SKIS. Your VIN may include SKIS so be aware that if you give the seller your VIN they may program it for SKIS (if they can(?))
__________________
If we have data, letís look at data. If all we have are opinions, letís go with mine.

Man who stands in front of Jeep gets tired. Man who stands behind Jeep gets exhausted.
CCKen is offline   Reply With Quote
Unread 03-19-2014, 01:53 PM   #34
who_datjeep
Registered User
2001 XJ Cherokee 
 
Join Date: Sep 2012
Location: Houston, TX
Posts: 221
Results:
Absolutely no noises with connector C3 connected. No EVAP purge solenoid clicking, no fuel pump running. So it does not appear to be a wire fault. It must be the PCM.

I ordered a remanufactured PCM from Auto Module Source last December. I gave them my VIN and they said they programmed it. I verified that they had the correct VIN written down. When one pulls up the build sheet for my VIN, they can see SKIS listed. How could they have messed that up? The SKIM needs to be physically present in order to program it?

Should I get a replacement PCM?

I also have a multimeter with me so I can use that if necessary.

Thanks,
Kevin
who_datjeep is offline   Reply With Quote
Unread 03-19-2014, 02:12 PM   #35
CCKen
Web Wheeler
 
CCKen's Avatar
1999 XJ Cherokee 
 
Join Date: Jul 2011
Location: Canton, MI
Posts: 1,890
Quote:
Originally Posted by who_datjeep View Post
Results:
Absolutely no noises with connector C3 connected. No EVAP purge solenoid clicking, no fuel pump running. So it does not appear to be a wire fault. It must be the PCM.

Do you mean with C3 disconnected? If so, it would mean there's no short to ground in the fuel pump relay control coil wire. The EVAP solenoid won't cycle with C3 disconnected anyway.

I ordered a remanufactured PCM from Auto Module Source last December. I gave them my VIN and they said they programmed it. I verified that they had the correct VIN written down. When one pulls up the build sheet for my VIN, they can see SKIS listed. How could they have messed that up? The SKIM needs to be physically present in order to program it?

I'm not sure about this but I don't think so. But it would need to be installed with a serviceable SKIM to program the transponder key/SKIM/PCM together. I could be wrong, but I think the PCM can be programmed seperate from the SKIM to enable SKIS programming in the vehicle. Where's this PCM you ordered from Auto Module Source last December - installed?

Should I get a replacement PCM?

I think so...without SKIM.

I also have a multimeter with me so I can use that if necessary.

I don't know what to tell you now. It seems that with the PCM disconnected and the fuel pump doesn't run it would point to the PCM.

Thanks,
Kevin
.
__________________
If we have data, letís look at data. If all we have are opinions, letís go with mine.

Man who stands in front of Jeep gets tired. Man who stands behind Jeep gets exhausted.
CCKen is offline   Reply With Quote
Unread 03-19-2014, 08:47 PM   #36
who_datjeep
Registered User
2001 XJ Cherokee 
 
Join Date: Sep 2012
Location: Houston, TX
Posts: 221
Thanks for the help CCKen!

Yes, that's what I meant. When the connector was disconnected.

I'll have to ask if the PCM can be programmed for that without the SKIM present. The remanufactured PCM is what has been installed since the start of this thread.

Why can't I have SKIM? That's a feature I would prefer to have as it can prevent vehicle theft.

Thanks for the help,
Kevin
who_datjeep is offline   Reply With Quote
Unread 03-20-2014, 07:27 AM   #37
who_datjeep
Registered User
2001 XJ Cherokee 
 
Join Date: Sep 2012
Location: Houston, TX
Posts: 221
Also, would it have been the SKIM not being programmed that caused the PCM to ground the fuel pump and EVAP purge solenoid circuits?

Or what else could have made the problem with the PCM? I want to verify the problem with the PCM so that the new PCM doesn't have the same problem.

Thanks,
Kevin
who_datjeep is offline   Reply With Quote
Unread 03-20-2014, 09:10 AM   #38
CCKen
Web Wheeler
 
CCKen's Avatar
1999 XJ Cherokee 
 
Join Date: Jul 2011
Location: Canton, MI
Posts: 1,890
Quote:
Originally Posted by who_datjeep View Post
Also, would it have been the SKIM not being programmed that caused the PCM to ground the fuel pump and EVAP purge solenoid circuits?

No, I don't think so. It may be a PCM fault aside of any SKIS issue. Generally, if there is a SKIS issue the PCM will disable the engine, not keep the fuel pump running.

Or what else could have made the problem with the PCM? I want to verify the problem with the PCM so that the new PCM doesn't have the same problem.

Thanks,
Kevin
Before getting into SKIS at this time you can do a check of the ground signal from the PCM to the fuel pump relay socket in the PDC.

Remove the fuel pump relay from the PDC.

Plug PCM C3 back in.

Refer to the fuel pump circuit diagram above and the PDC layout above.

You'll be using a digital voltmeter for this check. First starting with it set at 20 VDC, then if neccessary, set to 2 VDC.

Look at the FP diagram. See the relay pin connector at the relay "C3". This is the ground control from the PCM.

Now look at the PDC layout. See the fuel pump relay socket pin "3". This is the same as "C3" on the diagram.

With the FP relay removed, key to OFF/LOCK, voltmeter set to 20 VDC.

Measure the voltage at the FP relay pin cavity 3 in the PDC, using the battery negative post as the ground for the voltmeter.

Normally you would see between .01 and .150 volts. If you see battery voltage (12 volts), there's a problem with the PCM FP relay control coil ground driver.

If you see a very low, or no, voltage, switch the meter to 2 VDC and see what voltage you get.

If you get no voltage at all at pin cavity 3 in the PDC, try at pin cavity 5. Some of the Chrysler diagrams have changed pin cavities from what would normally be the ground control pin cavity to how they wired the PDC.

If you do see the low voltage (.01 to .150), turn the key to RUN and read the voltage again. There should be very little change in the voltage reading from key OFF to key RUN (in a normal situation).

As far as the EVAP Solenoid cycling constantly, it should only cycle after the PCM enters closed loop (or thereabouts). The Solenoid gets a constant 12 volts (White wire) when the key is to RUN, and the PCM provides a pulsated ground to the Solenoid (Pink/Black tracer wire) to cycle (Duty Cycle) the purge valve. There's no way the Solenoid should cycle with the key to off. Even if the Solenoid ground control wire was shorted to ground it wouldn't pulse/cycle the Solenoid. PCM fault if it constantly cycles the Solenoid when the key is OFF.

~~~~~~~

SKIS:

Read the attached pages extracted from the 2000 XJ FSM about the SKIS. I've added a red bar in the margin of the text that you should read.

If you have any questions about the PCM you should contact the place you bought the PCM from and ask them about prepping the PCM for SKIS, and/or contact a Jeep service center and ask them about it, and what you should do concerning getting your Jeep to the dealer for complete SKIS programming.



__________________
If we have data, letís look at data. If all we have are opinions, letís go with mine.

Man who stands in front of Jeep gets tired. Man who stands behind Jeep gets exhausted.
CCKen is offline   Reply With Quote
Unread 03-20-2014, 09:23 AM   #39
who_datjeep
Registered User
2001 XJ Cherokee 
 
Join Date: Sep 2012
Location: Houston, TX
Posts: 221
Whoa that's awesome info. I'll get back with the results.

Thanks,
Kevin
who_datjeep is offline   Reply With Quote
Unread 03-21-2014, 08:24 AM   #40
who_datjeep
Registered User
2001 XJ Cherokee 
 
Join Date: Sep 2012
Location: Houston, TX
Posts: 221
Okay,

Here are the results. With key to off/lock, neither pin cavity three nor pin cavity 5 showed any voltage. With key to run, pin cavity 5 showed 10.8. That was with the setting at 20 VDC. I didn't see any 2 VDC setting.

Also, my battery is almost dead with all the cranking I was doing. I am going to bring it to get charged. Which one's the complete charge? The trickle charge? Because last time I brought it to get charged, it only took about two hours., which makes me think it was some kind of quick charge.

Thanks,
Kevin
who_datjeep is offline   Reply With Quote
Unread 03-21-2014, 11:18 AM   #41
Millermagic
Registered User
2000 XJ Cherokee 
 
Join Date: Apr 2007
Location: Syracuse, New York
Posts: 1,904
Trickle charger is really only if it's sitting on its own with a fully charged battery and you don't want it to discharge over the course of a few months.

I would just buy a charger. You *can* quick charge them , but it's better to put it on a 2 amp charge and let it run overnight.
__________________
2000 XJ - 3.5'' Lift & Skinny Mudders.
Previous: A CJ, Few TJs and JK.
Millermagic is offline   Reply With Quote
Unread 03-22-2014, 12:48 AM   #42
justanotherjpr
Registered User
 
Join Date: Nov 2007
Posts: 6,336
Good luck with fix! Subbing to see what the resolution is.
__________________
Quote:
Originally Posted by Motorcharge View Post
So do you actually hear your thoughts in your head or is it just sort of a dull roar before you smash your face into your keyboard and just submit whatever dumb **** ended up on the page?
justanotherjpr 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.