Go Back   Jeep Garage - Jeep Forum > Jeep Platform Discussion > Grand Cherokee - WK > Troubleshooting/Problems

Join Jeep Garage Today
Reply
 
Thread Tools Display Modes
 
  #1  
Old 06-08-2012, 05:16 PM
RustyAxeCamp's Avatar
Member
My Jeep: 2009 WK
 
Join Date: Dec 2011
Location: Midland, MI, USA
Posts: 12
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 1124
RustyAxeCamp is on a distinguished road
Check Engine - Code P0456

Did the turn key code check and got P0456.

Gas cap might have been loose..

That it? Tighten it and drive for a while and the light should go off?

When do I take her to the Dr?
__________________

__________________
Reply With Quote
  #2  
Old 06-08-2012, 08:43 PM
Senior Member
My Jeep: 2006 5.7L WK
 
Join Date: Dec 2009
Location: Home of the Mountain Blue Bird
Posts: 1,064
Thanks: 0
Thanked 26 Times in 24 Posts
Rep Power: 155090
jeepgcoman has a reputation beyond reputejeepgcoman has a reputation beyond reputejeepgcoman has a reputation beyond reputejeepgcoman has a reputation beyond reputejeepgcoman has a reputation beyond reputejeepgcoman has a reputation beyond reputejeepgcoman has a reputation beyond reputejeepgcoman has a reputation beyond reputejeepgcoman has a reputation beyond reputejeepgcoman has a reputation beyond reputejeepgcoman has a reputation beyond repute
Re: Check Engine - Code P0456

From the FSM:

P0456-EVAP PURGE SYSTEM SMALL LEAK

Theory of Operation
The theory behind the Natural Vacuum Leak Detection (NVLD) is adherence to the Ideal Gas Law. Pressure in a

sealed vessel will change linearly as a function of the temperature of the gas in the vessel. Even small leaks will
allow the pressure in the vessel to come to equilibrium with the atmospheric pressure. After key-off and a calibrated
amount of time, cool down from operating temperatures or diurnal ambient temperature the system pressure will
force the system to go negative or draw a vacuum if there is no leak. When the vacuum level reaches 1” H2O (0.25
KPA) the NVLD vacuum switch closes. This sends a signal to the NGC freezing a timer and registering a pass. If
a switch closure is not detected an assessment of leak size will be made.



When Monitored:
Ignition off. Fuel Level less than 88%. Ambient Temperature between 4C and 43C (39F and 109F) Close

Loop fuel system.


Set Condition:
Due to temperature changes, a vacuum is created in the fuel tank and EVAP system. With the EVAP system

sealed, the PCM monitors the NVLD switch. If the NVLD switch does not close within a calibrated time allowance,
an error is detected by the PCM. One Trip Fault. Three good trips to turn off the MIL.
Possible Causes
EVAP PURGE SYSTEM LEAK

EVAP PURGE SOLENOID

You may also want to PM member, Walt, and see if he may be able to help you. He also lives in Midland.

__________________

__________________
05 LX/RT & 06 WK/GCO, modded similarly, MDS "ON" Light, Vortex Gens, Debadged, DashHawk, BT Catch Can, SRT CAI W/Add Air Inlet, K&N Filter, Sonnax Trans Press Booster, SC Tuner W/Adv Trans Tuning App, DS Tuner, Cust tube headers w/3 in. catback, Bilsteins, SRT frt/rear bumpers, Eibach SRT Lwr Sprgs & Sways, FRI Sidewinder Cam Adv 2*, 6.1 valvetrain, SLP 25% UD Pulley, BBK 90mm TB, SOS Coils/.060 plug gaps. 20 in. SRT Reps.
Reply With Quote
  #3  
Old 06-08-2012, 08:54 PM
RustyAxeCamp's Avatar
Member
My Jeep: 2009 WK
 
Join Date: Dec 2011
Location: Midland, MI, USA
Posts: 12
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 1124
RustyAxeCamp is on a distinguished road
Re: Check Engine - Code P0456

Quote:
Originally Posted by jeepgcoman View Post
You may also want to PM member, Walt, and see if he may be able to help you. He also lives in Midland.

He PMd me. Thanks guys!
__________________
Reply With Quote
  #4  
Old 06-08-2012, 08:55 PM
DAVY27's Avatar
Premium Member
Photobucket
 
Join Date: Jun 2009
Location: City that Never Sleeps
Posts: 9,268
Thanks: 471
Thanked 205 Times in 180 Posts
Rep Power: 1660271
DAVY27 has a reputation beyond reputeDAVY27 has a reputation beyond reputeDAVY27 has a reputation beyond reputeDAVY27 has a reputation beyond reputeDAVY27 has a reputation beyond reputeDAVY27 has a reputation beyond reputeDAVY27 has a reputation beyond reputeDAVY27 has a reputation beyond reputeDAVY27 has a reputation beyond reputeDAVY27 has a reputation beyond reputeDAVY27 has a reputation beyond repute
Garage
Send a message via AIM to DAVY27
Re: Check Engine - Code P0456

disc the neg terminal and then reconnect it. if the light comes back it might be the evap system.
__________________

2009 Jeep Grand Cherokee SRT Design
SRT Exterior,Magnaflow 14590 w/ SRT resonators,V2 CF Medic Hood,Injen Powerflow Intake,Flying Ryan Ported TB,Custom Painted Halo Headlights,HID lows/fogs,SRT Springs,Stillens,Gloss Black SRT Reps,Mopar Spoiler, Custom Painted Moldings with Snakeskin green GC letterings, Mopar Stripe,Tinted LED tails/rear fogs, TLS Harness,Switchbacks, Stage6 5" Tips,Custom Door Handle Leds,5% Tint,Altec Plate,HID Reverse,Mopar Front Emblem/ Rear Logo,Powerwire,Interior Leds,RGB LED cupholders,Mygig,Weathertech Mats,LXHarness Leds,Rear Cargo Light Mod,Lockpic V4,GlossBlack Vinyl Interior Pieces
Reply With Quote
  #5  
Old 06-09-2012, 12:55 AM
2005JGC's Avatar
Senior Member


My Jeep: 2005 4.7L WK
 
Join Date: Nov 2010
Location: Portland, OR
Posts: 2,751
Thanks: 51
Thanked 69 Times in 58 Posts
Rep Power: 1653064
2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute
seems 9 times out of 10 the thing that causes this code along with other evap leak codes us the esim switch mounted to the charcoal canister... Its a pretty cheap part and once you understand how it detaches its super easy to replace.

Sent from my SCH-I500 using Tapatalk 2
__________________
2005 Jeep Grand Cherokee - Gone but not forgotten!

Reply With Quote
  #6  
Old 06-11-2012, 11:12 AM
RustyAxeCamp's Avatar
Member
My Jeep: 2009 WK
 
Join Date: Dec 2011
Location: Midland, MI, USA
Posts: 12
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 1124
RustyAxeCamp is on a distinguished road
Re: Check Engine - Code P0456

light went off the next day. Code was still in there. I unhooked battery and reset today. Started engine and let run for 3-4 minutes. No codes. If it doesn't come back, figure it was the cap?
__________________
Reply With Quote
  #7  
Old 06-11-2012, 02:39 PM
2005JGC's Avatar
Senior Member


My Jeep: 2005 4.7L WK
 
Join Date: Nov 2010
Location: Portland, OR
Posts: 2,751
Thanks: 51
Thanked 69 Times in 58 Posts
Rep Power: 1653064
2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute
Re: Check Engine - Code P0456

evap codes will take a couple days to reset especially small leak, it requires a cold soak after a drive cycle to run the monitor so it likely wont come right back... but yes, if it doesnt come back it would be safe to assume it was the cap.
__________________
2005 Jeep Grand Cherokee - Gone but not forgotten!

Reply With Quote
  #8  
Old 08-29-2012, 04:43 PM
hoffmanestates's Avatar
Senior Member
 
Join Date: Nov 2011
Posts: 1,067
Thanks: 1
Thanked 5 Times in 5 Posts
Rep Power: 2534
hoffmanestates has a reputation beyond reputehoffmanestates has a reputation beyond reputehoffmanestates has a reputation beyond reputehoffmanestates has a reputation beyond reputehoffmanestates has a reputation beyond reputehoffmanestates has a reputation beyond reputehoffmanestates has a reputation beyond reputehoffmanestates has a reputation beyond reputehoffmanestates has a reputation beyond reputehoffmanestates has a reputation beyond reputehoffmanestates has a reputation beyond repute
mine just popped up two days after emissions testing ...

Sent from my LG-P999 using Tapatalk 2
__________________
Reply With Quote
  #9  
Old 08-30-2012, 06:21 AM
06grand's Avatar
Member
My Jeep: 2006 5.7L WK
 
Join Date: Jun 2012
Location: Boston, MA
Posts: 47
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 968
06grand is on a distinguished road
Re: Check Engine - Code P0456

Im having the same problem, my mechanic is finally stumped. Ive had the system smoked, checked and replaced the gas cap. However, I may be onto something after seeing someone mention the esim switch above. Googled ESIM switch and got this [PDF] Chrysler Evaporative Leak Detection Systems



Some pretty useful info if you still have problems.
__________________
06 5.7 Limited - DVD/NAV, Front 30% tint, Mopar CAI, Mopar door sills, SRT-8 pedals, LED Interior, BT Catch Can
Reply With Quote
  #10  
Old 08-30-2012, 06:45 AM
hoffmanestates's Avatar
Senior Member
 
Join Date: Nov 2011
Posts: 1,067
Thanks: 1
Thanked 5 Times in 5 Posts
Rep Power: 2534
hoffmanestates has a reputation beyond reputehoffmanestates has a reputation beyond reputehoffmanestates has a reputation beyond reputehoffmanestates has a reputation beyond reputehoffmanestates has a reputation beyond reputehoffmanestates has a reputation beyond reputehoffmanestates has a reputation beyond reputehoffmanestates has a reputation beyond reputehoffmanestates has a reputation beyond reputehoffmanestates has a reputation beyond reputehoffmanestates has a reputation beyond repute
ill look into it

Sent from my LG-P999 using Tapatalk 2
__________________

__________________
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Engine Code- P0456 SRTWJ04 Troubleshooting/Problems 12 03-05-2013 10:04 PM
check engine light code wont display on 06 3.7 06CherokeeMan Troubleshooting/Problems 9 11-26-2012 04:52 PM
Check Engine, check guages, fan on high MattB5694 Wrangler-YJ, TJ & JK 3 06-08-2012 01:54 AM
P2004 check engine code on 2007 Patriot nubian Compass and Patriot 1 06-06-2012 10:00 PM
check engine light code 99limited Troubleshooting/Problems 4 03-27-2010 09:43 PM

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 05:35 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Copyright 2012 - JeepGarage.Org
The Jeep Grand Cherokee Owners Community

JeepGarage.org is in no way associated with or endorsed by Chrysler Group LLC.