|06-07.5 LBZ & LLY Duramax Powertrain Discussion of components that are directly involved in the power production and all that is needed to get and keep the truck moving . Engine , Transmission Ect|
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|02-04-2010, 05:26 PM||eBay Motors #1 (permalink)|
Duramax Forum Supporter
Join Date: Jan 2010
Engine code P0128
Anyone know why im getting engine coolant below thermostat regulating temp? This only happens when I'm babying the truck if I play somewhat with the throttle the code dosen't show.
Who was the tattletale? Little bitch!
|02-04-2010, 06:18 PM||eBay Motors #3 (permalink)|
Join Date: Sep 2009
Location: Baldwin, MI
The ECM is calculating an expected Coolant Temp given the fuel that has been burned and the time that it has been burning it. If the coolant temp does not meet or exceed the calculated temp, you get the code.
Check for proper coolant level.
Perform Coolant System Leak Test.
Inspect fan for proper operation.
Inspect the fan belt to ensure it is in good operating condition?
Remove thermostats and verify proper operation. Bring to boil in a pot of water and see what temps they open and close at. Start opening ~ 160 Fully open at ~ 180 Degrees F roughly.
Could also be a bad ECT Sensor. You can do a resistance check at various temps. At 0 degrees F Res = 9420 ohms At 50 degrees F Res = 973 ohms at 100 degrees F Res = 177 ohms, at 150 degrees F Res = 47 ohms.
This condition could also be caused by air in the coolant system. That could possibly be an indicator of a bad head gasket. After shutting the warmed engine off, and letting it set for several hours, check the upper Rad hose to see if it is hard. If it is hard, you probably should test for a headgasket failure.
Did you try running it at a different tune to see if you still get the code? If all the above is within Spec, then the tuner could be causing the ECM to give you a bad calculation.
'09 2500 Z-71 HD, Wyoming Edition
'06 Desert Fox TH
'53 Cranky Ex-Spouse
Last edited by Len Todd; 02-04-2010 at 06:21 PM.
|02-04-2010, 07:10 PM||eBay Motors #6 (permalink)|
Join Date: Jun 2008
Location: So. Cal
That was a good response from Len Todd--
Diesels like a certain temperature to run well and be efficent-- it is possible that someone replaced the thermostats with cooler ones. Most have a stamp on that shows the set temperature.
Chevy 04.5 LLY, 2X, shell, XDR, MikeL Heavy duty up-grade, 6spd, TransGo, deep pan, de-badged, 65 Gallon replacement Aero tank, LBZ-mp, Kennedy pump, shimmed, Pre-fuel filter, tow mirrors, BU cam, gauges, GPS, Sirius, bags, custom grille, fender vents, HD trans cooler- Curt front hitch, footwell lights, load lights, Studs, head gaskets.--- Jerry
|02-05-2010, 06:24 PM||eBay Motors #7 (permalink)|
Join Date: Jul 2007
Location: stillwater NJ
where was this answer for me 2 month ago lol. I started getting this code after I had bigger nozzles put on my injectors when the cooler temperatures hit here. I Was able to adjust the tuning to almost eliminate the code. still pops up every once in a while usually after its partially warmed up and I jump on it to get into traffic or something
2006 GMC 2500HD cc,sb , lbz, stealth gray
a few go kinda fast goodies