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Unread 10-14-2013, 11:40 AM   #1
DakMan96
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Unsolvable problem with the WJ. HELP

I have a 1999 Jeep Grand Cherokee Laredo 4.0. I'm throwing the code p1595. The problem is my acceleration is random sometimes, I'll floor it and sometimes it goes full throttle then dies off a little for a second then goes full again. After I drive it for a while, and turn it off, it has trouble starting up again after its been off and turned back on 2 times. The RPMs drop to 300 or 400 before stalling. I even hold the petal down and it does nothing. Sometimes I get a hard hitting bang in the engine bay right in front of the drivers side. After I let it sit for 15 or so minutes, it'll start right back up and the cycle starts over. So what's going on guys?! Thanks in advance

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Unread 10-14-2013, 12:19 PM   #2
WJ4x4LIFE
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Does your "cruise control" work at all in your WJ? I would assume that you know what that code P1595 already, if not. I gave you a bit of a push below to start off. If the cruise control won't engage, the fault could be any number of things: a bad servo unit, a leaky vacuum reservoir for the cruise control servo, a bad cruise control switch, or even a fault inside the engine computer. (the PCM runs the cruise control on your Jeep)

---------------------------------------

P1595 -Speed Control Solenoid Circuits issue.

An open or shorted condition detected in either of the speed control vacuum or vent solenoid control circuits.

Image references: servo underneath your battery.






------------------------------------

I would say there is a large vacuum leak or connector may have came loose somewhere and time to search and fix.

-------------------

Here's another tip that one of our other experts suggested I pass along to you:

If your Jeep is a 4.0L, they are notorious for the vacuum line for the cruise control falling off of the underside of the intake manifold, it will also cause the hvac unit to only blow in defrost.
Not that you may have this problem, just a reoccurring thing that is linked together sometimes.
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Unread 10-14-2013, 12:55 PM   #3
new2site
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See here.... might be the cause:

http://www.eanswer.com/chrysler/70kv...595-error.html
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Unread 10-14-2013, 04:54 PM   #4
tim0
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Well, Im not sure the P1595 code has much to do with the issue you are reporting.
If you have an idle issue and wont rev at full throttle, I would check the IAC and TPS. Clean your IAC, this is simple to do.
With the Key Off, remove the IAC and use spray carb/choke cleaner to clean all the carbon off, spray the intake port out as well.
let sit for several minutes to evaporate spray cleaner. Then lightly spray IAC with WD40 before instalation.
Bad TPS could affect your cruise control operation as well but I dont think it would cause this code.
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Unread 10-15-2013, 08:28 PM   #5
DakMan96
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Quote:
Originally Posted by tim0 View Post
Well, Im not sure the P1595 code has much to do with the issue you are reporting.
If you have an idle issue and wont rev at full throttle, I would check the IAC and TPS. Clean your IAC, this is simple to do.
With the Key Off, remove the IAC and use spray carb/choke cleaner to clean all the carbon off, spray the intake port out as well.
let sit for several minutes to evaporate spray cleaner. Then lightly spray IAC with WD40 before instalation.
Bad TPS could affect your cruise control operation as well but I dont think it would cause this code.
Thanks for the advice, I'll check that out. But so everyone knows my cruise control DOES work, which is what makes this so confusing to me
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Unread 10-15-2013, 08:29 PM   #6
DakMan96
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Quote:
Originally Posted by WJ4x4LIFE View Post
Does your "cruise control" work at all in your WJ? I would assume that you know what that code P1595 already, if not. I gave you a bit of a push below to start off. If the cruise control won't engage, the fault could be any number of things: a bad servo unit, a leaky vacuum reservoir for the cruise control servo, a bad cruise control switch, or even a fault inside the engine computer. (the PCM runs the cruise control on your Jeep)

---------------------------------------

P1595 -Speed Control Solenoid Circuits issue.

An open or shorted condition detected in either of the speed control vacuum or vent solenoid control circuits.

Image references: servo underneath your battery.






------------------------------------

I would say there is a large vacuum leak or connector may have came loose somewhere and time to search and fix.

-------------------

Here's another tip that one of our other experts suggested I pass along to you:

If your Jeep is a 4.0L, they are notorious for the vacuum line for the cruise control falling off of the underside of the intake manifold, it will also cause the hvac unit to only blow in defrost.
Not that you may have this problem, just a reoccurring thing that is linked together sometimes.
Great info. I'll be sure to check out as much as I can, but my cruise control is working like a charm. So I'll scratch that one off the list.
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Unread 10-18-2013, 12:03 PM   #7
DakMan96
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I noticed one more problem I'm having. Terrible gas mileage due to the fact I'm getting very high RPMs for little acceleration. At 60mph, I'm getting 15mpg instant
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Unread 10-18-2013, 07:33 PM   #8
tim0
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What RPM is the 4.0 running at 60 MPH? should be just under 2000. You still may not be shifting all the way in to Overdrive.
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Unread 10-20-2013, 10:14 PM   #9
DakMan96
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Originally Posted by tim0 View Post
What RPM is the 4.0 running at 60 MPH? should be just under 2000. You still may not be shifting all the way in to Overdrive.
Nope, I'm over 2000. I'll check next time but I think it's about 2150-2200. If it's not shifting all the way into overdrive how can i fix that?
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Unread 10-21-2013, 10:57 AM   #10
OffroadOran
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Quote:
Originally Posted by DakMan96

Nope, I'm over 2000. I'll check next time but I think it's about 2150-2200. If it's not shifting all the way into overdrive how can i fix that?
I figured i would add that my 4.0 runs at roughly 1700 rpms at 60 mph. And as for overdrive not working, are you sure you didnt turn off the overdrive or it isnt stuck in the off position fir whatever reason?
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Unread 10-21-2013, 01:27 PM   #11
rdkendrick
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It's possible that your TCM has never been re-flashed to give you the 5th gear. Sent from my iPad using my fingers
http://www.wjjeeps.com/tsb/tsb_wj_1802501.pdf
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Unread 10-21-2013, 04:44 PM   #12
OffroadOran
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Quote:
Originally Posted by rdkendrick
It's possible that your TCM has never been re-flashed to give you the 5th gear. Sent from my iPad using my fingers
http://www.wjjeeps.com/tsb/tsb_wj_1802501.pdf
The tranny behind the 4.0 (42re) only has 4 gears and cannot be flashed, since there is no flash for it. Only the tranny behind the v8s can be flashed
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Unread 10-21-2013, 06:44 PM   #13
rdkendrick
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Originally Posted by OffroadOran View Post
The tranny behind the 4.0 (42re) only has 4 gears and cannot be flashed, since there is no flash for it. Only the tranny behind the v8s can be flashed
Yeah, I started to wonder that, after I posted. I couldn't remember if that applied to the 42re. Thanks for the reminder.

Sent from my iPad using my fingers
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Unread 10-21-2013, 06:56 PM   #14
OffroadOran
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Quote:
Originally Posted by rdkendrick View Post
Yeah, I started to wonder that, after I posted. I couldn't remember if that applied to the 42re. Thanks for the reminder.

Sent from my iPad using my fingers
anytime
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Unread 10-21-2013, 07:09 PM   #15
DakMan96
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Quote:
Originally Posted by OffroadOran View Post

I figured i would add that my 4.0 runs at roughly 1700 rpms at 60 mph. And as for overdrive not working, are you sure you didnt turn off the overdrive or it isnt stuck in the off position fir whatever reason?
I was wrong, my RPMs are pretty normal. But I have a pretty big Los of power. As mentioned, I'll floor it and it sort of hesitates and goes just a little for 3 seconds or so then picks up, but it's still nowhere the power it should have. Id like to add also I smell gas sometimes when I floor it in park trying to keep the RPMs up (which doesn't always work)
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