P0128 code coolant temp low - Page 4 - Jeep Garage - Jeep Forum

Go Back   Jeep Garage - Jeep Forum > Jeep Platform Discussion > Grand Cherokee - WK2 - > Trouble Shooting/Problems/Service

Join Jeep Garage Today
Reply
 
Thread Tools Display Modes
 
  #37  
Old 11-19-2015, 03:09 PM
Member
My Jeep: 2011 3.6L
 
Join Date: Sep 2014
Location: Reading, MA
Posts: 244
Thanks: 5
Thanked 21 Times in 16 Posts
Rep Power: 1062
rlefig is on a distinguished road
Garage
Re: P0128 code coolant temp low

i drained a gallon and it was below

Reply With Quote
Sponsored Links
Advertisement
 
  #38  
Old 11-19-2015, 03:42 PM
WickedXJ's Avatar
Member
My Jeep: 2011 3.6L WK2
 
Join Date: Sep 2012
Location: North Vancouver, BC Canada
Posts: 248
Thanks: 10
Thanked 18 Times in 17 Posts
Rep Power: 4009
WickedXJ has a reputation beyond reputeWickedXJ has a reputation beyond reputeWickedXJ has a reputation beyond reputeWickedXJ has a reputation beyond reputeWickedXJ has a reputation beyond reputeWickedXJ has a reputation beyond reputeWickedXJ has a reputation beyond reputeWickedXJ has a reputation beyond reputeWickedXJ has a reputation beyond reputeWickedXJ has a reputation beyond reputeWickedXJ has a reputation beyond repute
Re: P0128 code coolant temp low

Quote:
Originally Posted by rlefig View Post
i drained a gallon and it was below
I should have drained some, did not, my wide oil pan caught it all though.

All you need is a socket set and pliers for re/re the rad hose onto thermostat. Phillips screwdriver for bleeder screw too
__________________
2011 WK2 RRO 2.5" lift
ORA 1, Security & Convenience Group, Tow package
275/65/18 Duratracs, Procomp 7036 Wheels
2014 HID/LED headlights
Auto HVAC, 430n, lockpick, rear view camera, some plastidip...
Reply With Quote
  #39  
Old 11-20-2015, 10:44 AM
New Member
 
Join Date: Nov 2015
Posts: 3
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
abr757 is on a distinguished road
Re: P0128 code coolant temp low

One more question. I know I'll need to pull off the air intake to get to the thermostat. On a 3.6 Laredo, do I need to pull off the plastic skid plate to get to the radiator drain valve or can I reach in there without removing it? Will I need to raise the car on jack stands?

I'm doing this on a friend's car and want to be sure we know what we're in for. Thanks again.
Reply With Quote
  #40  
Old 11-21-2015, 02:18 PM
New Member
 
Join Date: Nov 2015
Posts: 3
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
abr757 is on a distinguished road
Re: P0128 code coolant temp low

Job all done. Thanks for the help. For those considering a few specifics on the VERY manageable repair.

You need to pull of the air intake system. See this from 2:00-2:30. You'll need an 8mm socket to loosen the clamp on the housing (passenger side, near the jump point).

Draining 3/4 gallon of coolant got us below the thermostat level. 1/2 tubing fits on the radiator drain port, so we ran tubing past the plastic underpanel so that we could drain easily into a jug.

Bolts for the thermostat housing at 10mm.

The bleeder screw on the thermostat housing is a little difficult to reach once you re-install the air intake, but you can do it with the screwdriver angled towards the windshield.

No pics, but the ones earlier in the thread were super helpful.
Reply With Quote
  #41  
Old 11-28-2015, 11:13 PM
New Member
My Jeep: 2011 3.6L WK2
 
Join Date: Mar 2012
Location: Maryland
Posts: 2
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
dbm683 is on a distinguished road
Re: P0128 code coolant temp low

I have had this code come up once. I checked the code and then cleared the code. It has not returned. As a precaution I was thinking about changing the t'stat but could not find the info in the wk2jeep website. Could someone send it to me?
Reply With Quote
  #42  
Old 11-29-2015, 05:56 PM
Member
My Jeep: 2014 3.0L WK2
 
Join Date: Dec 2013
Location: Kerrville, TX
Posts: 614
Thanks: 58
Thanked 88 Times in 71 Posts
Rep Power: 1779
philbytx has a reputation beyond reputephilbytx has a reputation beyond reputephilbytx has a reputation beyond reputephilbytx has a reputation beyond reputephilbytx has a reputation beyond repute
Garage
Re: P0128 code coolant temp low

Check this out: TSB has your code in it..

http://www.wk2jeeps.com/tsb/tsb_wk2_1809415.pdf
__________________
Phil C.
2014 GC Overland 4x4, 3.0CRD, ATG, ORAII ("Smiffy")
2015 Lance 1685 Travel Trailer "#4"
2011 Kia Optima EX-L ("MC"
2003 BMW R1150RT "Darth"
Reply With Quote
  #43  
Old 11-30-2015, 07:35 AM
Ratchet's Avatar
Premium Member
My Jeep: 2014 5.7L WK2
 
Join Date: May 2011
Location: Wilson, NC
Posts: 539
Thanks: 19
Thanked 25 Times in 25 Posts
Rep Power: 6424
Ratchet has a reputation beyond reputeRatchet has a reputation beyond reputeRatchet has a reputation beyond reputeRatchet has a reputation beyond reputeRatchet has a reputation beyond reputeRatchet has a reputation beyond reputeRatchet has a reputation beyond reputeRatchet has a reputation beyond reputeRatchet has a reputation beyond reputeRatchet has a reputation beyond reputeRatchet has a reputation beyond repute
Re: P0128 code coolant temp low

Quote:
Originally Posted by philbytx View Post
Check this out: TSB has your code in it..

http://www.wk2jeeps.com/tsb/tsb_wk2_1809415.pdf
Note the tsb link is for 3.0 diesel engines only.
__________________
2014 WK2 Overland - Billet Silver
Reply With Quote
  #44  
Old 11-30-2015, 03:13 PM
Member
My Jeep: 2014 3.0L WK2
 
Join Date: Dec 2013
Location: Kerrville, TX
Posts: 614
Thanks: 58
Thanked 88 Times in 71 Posts
Rep Power: 1779
philbytx has a reputation beyond reputephilbytx has a reputation beyond reputephilbytx has a reputation beyond reputephilbytx has a reputation beyond reputephilbytx has a reputation beyond repute
Garage
Re: P0128 code coolant temp low

DUH! LOL
__________________
Phil C.
2014 GC Overland 4x4, 3.0CRD, ATG, ORAII ("Smiffy")
2015 Lance 1685 Travel Trailer "#4"
2011 Kia Optima EX-L ("MC"
2003 BMW R1150RT "Darth"
Reply With Quote
  #45  
Old 12-07-2015, 11:31 PM
New Member
 
Join Date: Dec 2015
Posts: 4
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
MikeMidwest is on a distinguished road
Re: P0128 code coolant temp low

Quote:
Originally Posted by Ratchet View Post
padgett, here's what I have to go on regarding condtions for the P0128 to set.

When monitored: With the engine running, ambient temperature between 8C(17.6F) & 50C(122F), startup coolant temperature less than 50C(122F) and average vehicle speed greater than 16KPH(10MPH), untill the vehicle untill coolant temperature reaches 85C(185F).

Set conditions: The PCM detects that the actual coolant temperature falls too far below the predicted engine coolant temperature and the predicted engine coolant temperature reaches the predicted target value before the actual coolant temperature reached the actual coolant temperature target value. Two trip fault. Three good trips to turn off MIL.

Possible causes: The top two are most common.
-Low coolant
-Thermostat open
-Temperature sensor
-Signal circuit open
-Signal ground circuit open
-Signal circuit shorted to ground
-Signal circuit shorted to the (K900), (G931) sensor ground circuit
-Powertrain control module (PCM)

Glad to know I'm not the only guy running into this same problem.

I've got a 2011 Grand Cherokee Laredo 3.6L. Check engine light came on a while back and found it was throwing a P0128 code. I replaced my T-stat a couple of weeks ago and cleared the code, however it came back on a couple days later. (Bonus: I tried to clear it again, but the code wouldn't clear - not sure why...is that considered a 'hard' fault?)

I drove it on a short trip this weekend and noticed my temp never went above 168 degrees, per the on-dash engine diagnostic information. I am guessing it's my ECT sensor that needs replaced next.

First question, what is normal operating temp variance for mine? Am I truly low? I would assume so, based on the fault I'm receiving, but wanted to confirm. Next, if I tackle the ECT replacement, is it an easy swap/what should I look out for/etc. and should I choose an OEM part or not? (Here is an O'Reilly part suggestion: BWD WT5205 - Engine Coolant Temperature Sensor | O'Reilly Auto Parts) I will try to clear the fault afterward and see if it trips again - if it does, do I need to see the dealer? (Just like doctors, I do NOT like going to see the dealer...$$.)

I have been literally pulling my hair out on this for a while, until I saw this post. It's getting cold here in the Midwest and I REALLY want my remote start back.

A huge thanks guys - Mike

_____________________________
'11 Grand Cherokee Laredo
'97 Cherokee Sport
Reply With Quote
  #46  
Old 12-08-2015, 07:43 AM
Ratchet's Avatar
Premium Member
My Jeep: 2014 5.7L WK2
 
Join Date: May 2011
Location: Wilson, NC
Posts: 539
Thanks: 19
Thanked 25 Times in 25 Posts
Rep Power: 6424
Ratchet has a reputation beyond reputeRatchet has a reputation beyond reputeRatchet has a reputation beyond reputeRatchet has a reputation beyond reputeRatchet has a reputation beyond reputeRatchet has a reputation beyond reputeRatchet has a reputation beyond reputeRatchet has a reputation beyond reputeRatchet has a reputation beyond reputeRatchet has a reputation beyond reputeRatchet has a reputation beyond repute
Re: P0128 code coolant temp low

Quote:
Originally Posted by MikeMidwest View Post
Glad to know I'm not the only guy running into this same problem.

I've got a 2011 Grand Cherokee Laredo 3.6L. Check engine light came on a while back and found it was throwing a P0128 code. I replaced my T-stat a couple of weeks ago and cleared the code, however it came back on a couple days later. (Bonus: I tried to clear it again, but the code wouldn't clear - not sure why...is that considered a 'hard' fault?)

I drove it on a short trip this weekend and noticed my temp never went above 168 degrees, per the on-dash engine diagnostic information. I am guessing it's my ECT sensor that needs replaced next.

First question, what is normal operating temp variance for mine? Am I truly low? I would assume so, based on the fault I'm receiving, but wanted to confirm. Next, if I tackle the ECT replacement, is it an easy swap/what should I look out for/etc. and should I choose an OEM part or not? (Here is an O'Reilly part suggestion: BWD WT5205 - Engine Coolant Temperature Sensor | O'Reilly Auto Parts) I will try to clear the fault afterward and see if it trips again - if it does, do I need to see the dealer? (Just like doctors, I do NOT like going to see the dealer...$$.)

I have been literally pulling my hair out on this for a while, until I saw this post. It's getting cold here in the Midwest and I REALLY want my remote start back.

A huge thanks guys - Mike
Before you go any further, verify your coolant level is full. 180-190ish is the norm for most newer vehicles. From the semi low reported temperature, it sounds alot like you have a bit of air trapped in the system. Generally if an ETC was to fail, the reported temperature would be extremely high or either extremely low. However, when dealing with electrical componets, strange things can and will happen.
__________________
2014 WK2 Overland - Billet Silver
Reply With Quote
  #47  
Old 12-08-2015, 08:59 AM
Member
My Jeep: 2011 3.6L
 
Join Date: Sep 2014
Location: Reading, MA
Posts: 244
Thanks: 5
Thanked 21 Times in 16 Posts
Rep Power: 1062
rlefig is on a distinguished road
Garage
Re: P0128 code coolant temp low

The t-stat switch fixed my code. Like somebody else said make sure it is bled correctly via the screw on to of t-stat housing then I guess try the sensor.

good luck
Reply With Quote
  #48  
Old 01-12-2016, 07:45 PM
Member
My Jeep: 2011 3.6L WK2
 
Join Date: Apr 2011
Location: NJ
Posts: 112
Thanks: 4
Thanked 4 Times in 3 Posts
Rep Power: 2158
Benzie002 is on a distinguished road
Re: P0128 code coolant temp low

Just got the same code, will order a thermostat and hopefully fix the problem thanks for the bleeding procedure. says its a 203 degree stat. hot stuff!

BTW, I tried to clear the code and it keeps coming back on instantly, any idea why this happens? The coolant temp according to the dash is about 177 the gage is about a quarter.

Thanks
__________________
2011 Jeep Grand Cherokee Limited 3.6L
2005 Jeep Grand Cherokee Rocky Mountain 3.7L
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
HVAC- Temp Up/ Temp Down jeepinAl Trouble Shooting/Problems/Service 2 03-25-2015 11:51 AM
2011 3.6l Dtc p0128 jeepndango Trouble Shooting/Problems/Service 0 12-09-2013 09:41 PM
P0128 Error Code kyle.jg Troubleshooting/Problems Discussion 5 11-07-2012 09:49 PM
Error Code P0128 Daveyc Troubleshooting/Problems 3 08-14-2012 07:54 PM
coolant leak - rad cap - temp gauge rvtifer Troubleshooting/Problems Discussion 9 12-22-2010 03:23 PM

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 03:37 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2016, vBulletin Solutions, Inc.
Copyright 2012 - JeepGarage.Org
The Jeep Grand Cherokee Owners Community

JeepGarage.org is in no way associated with or endorsed by FCA US LLC. Chrysler, Dodge, Jeep, Ram, Mopar and SRT are registered trademarks of FCA US LLC.