ArcticJ

WOW that was fast...thats it... now I know it does us no good...if im reading it right, the recommendation to eliminate the codes is to swap the cord for a thermostat cord, disallowing the use above 0.... Im not looking forward to the upcoming 2-10 degree day and nights

Hello once again my cold weather friends... I too am curious about the cutters and thermostat modifiers out there...problems? codes? I started to get a code this year p0116 for the first time. The plug was in for about 3 hours with the temp about 4 degrees F. I mentioned on another post/reply that I can't find now that I read somewhere that GM issued a software update for diesels to eliminate/reduce the codes thrown from the heater being used above 0. The update was issued around march or april...this won't due most of any good with gassers I know, but hey... Stay in touch all

Hey cold weather lovers...missed you for awhile...(been working nights) I hate to revive what appears to be a dead post, but whats the deal with the heaters? Those that have cut, did you get any (additional) codes or problems (temp gauge? etc.) Are the heaters working? Are the codes coming on if the cut heater is used above...say 20? I cut one of my trucks plugs, used it in N. WI. when the temps were in the single digits and ultimately -25 one morning. Obviously the stock plug would have worked on that particular day, but on the mornings above 0, I plugged the truck in for a couple of hours before driving on two occassions (once up, I rarely move around until leaving for IL.) I had no problems...truck started nicely, no warning lights came on and everyone was happy. Those that have not cut, are you accepting the heater for what it is, useless unless in extreme temps? Has anyone tried that last mod? Problems? again, I hate to reopen but I just gotta know whats happening out there... Thank you Thanks

OK...new plug is on, but it hasn't been cold enough to run it...its only getting in the mid to high 20's... Whats the update with the other cutters problems...codes?

Hey redbugdave... I really appreciate your info and everyone else on this page...it's been extremely helpful. I'm just about ready to get that plug off and I will definitely leave enough to re-attach... No flowers here in chicago...were on our way to the great white north in a couple of days and it would be great if i could get this plug on and do a little test up there...the temps at night have been around 5-15 degrees...we'll see Thanks again to everyone for the info...keep it coming please

There's actually some logic in the P0116 DTC test that tries to determine if a block heater has been used. On the other hand, this is a type B code, which means the DTC test has to fail on two consecutive ignition cycles (in which the test runs) for it to turn the light on. So you're not in the clear yet on the light not coming on. <{POST_SNAPBACK}> Hey GMCStepSide...any problems yet...have you had the opportunity to use the heater a second time?

Chances are zero to none. This coolant temp rise test is a federal emission requirement. Talk to your legislators and see if you can get them to convince the EPA that you would like to have your truck warm when you start it up. GM has little say in this stuff. They have to certify the vehicle with the EPA and can't just change calibrations willy nilly. Any change that would affect emissions would have to go through the same certification process. <{POST_SNAPBACK}> Thats not so good news

I'm back....and you guys though I was nuts when I brought this thermostat "tumor" thing up... GMTECH, any chance of GM reprograming the computer as suggested in a previous post or are we stuck with useless heaters? Any other ideas? Didn't someone else lop off the plug and replace it? If so, did you experience the same issues? We have to figure this thing out...it kills me when I go north and start these trucks in 0-15 degree temps... To that, while snomoing last weekend, I saw a couple of new sleds plugged in...nice

Yeah, it is a bigger deal than you realize. This is not GM's decision. They have to meet certain standards that define what tests are run, when, and what the results must be to be in compliance. They can't just tweak things to suit their (or your) needs. As for your question as to whether or not the light will come on.... yes, after the second consecutive failure. Here's the full details on the criteria that must be met for DTC P0116 to run and what happens if it fails. This test appears to be able to detect if a block heater is in use, in which case the test aborts, but perhaps under some conditions, it may fail the test anyway. --------- Conditions for Running the DTC • The ignition is ON. • DTCs P0112, P0113, P0116, P0117, P0118, P0128, P0502, P0503 are not set. • The start-up IAT is more than -7°C (+20°F). • The vehicle has a minimum ignition OFF time of 10 hours. • DTC P0116 runs once per drive cycle when the above conditions are met. Conditions for Setting the DTC • The start-up ECT is more than the start-up IAT by 100°C (180°F). OR • The start-up ECT is more than the start-up IAT by 15°C (27°F), then the vehicle must be driven for more than 400 seconds over 24 km/h (15 mph). If the IAT sensor temperature decreases more than 8°C (14°F), a block heater is detected and the test is aborted. If the IAT sensor temperature does not decrease, a block heater was not detected and DTC P0116 sets. Action Taken When the DTC Sets The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records. Conditions for Clearing the MIL/DTC • The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. • A current DTC, Last Test Failed, clears when the diagnostic runs and passes. • A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. • Clear the MIL and the DTC with a scan tool. <{POST_SNAPBACK}> Ok..I see the criteria for the test...what if the engine was started once every 9 1/2 hours, or before the 10 hour mark,...not meeting the 10 hour criteria of a minimum of 10 hour off time. Would that avoid the diagnostic and thus the potential for the trouble code? And/or do you think this trouble code is a result of the heater being used when the temps are too high...above 30...and since it was generating this code, GM installed the thermostat to eliminate the grief? And unofficially, is it a big deal to circumvent the plug if it was only used in <15 degrees?

One more thought...does the check engine light come on or is the code just get stored away not to bother you until you bring your truck in? GM TECH...what do you think about all of this? MS3DALE? check this link out (If I didn't post it right, just copy and paste it in the address bar...does this help you tech guys out? [url=http://gearchatter.com/viewpost14669.php?sid=6e62b08960a65c17cee608d37bd822b1

YOU GUYS ARE UNBELIEVABLE...BEASLEY AND EVERYONE ELSE...THANK YOU FOR FINDING AN ANSWER...now the next set of questions Im not a tech or anything more than a garage mechanic...what I get out of that is the OBD (On Board Diag.?) will generate a DTC (Diag. Trouble Code?) #P0116 because the PCM (?) does not recognize or like the high starting temp or the coolant according to the coolant temperature sensor or the slow or out of ordinary warm up of the coolant because it is already warm... I can understand that, I think but why didnt GM, when faced with this situation, modify the PCM and it's dianostic procedures (probably a bigger deal than I know) or if inserting a thermostat, set the useable temp around 15 degrees? I used the heater on my 02 burb without problems or codes...perhaps someone (or alot of them) decided 40 degrees was too cold and plugged in the truck thus generating this DTC thing. Is there really a big difference if its 0 degrees or 10 degrees outside??? As for the plug cutting group...would this void out a warranty if a problem would arise? And with that, what problems could possibly arise if the heater was used with a new plug in temps of 15 degrees or colder? For those who have already cut...are you getting any DTC's yet? What kind of temps have you used it in and how many times? And ultimately, any special parameters for the new plug other than grounded? THANKS AGAIN...I CAN'T BELIEVE THE RESOLVE OF THIS GROUP...YOUR ALL AWESOME....

The block and heads on my 8.1L are still both iron, yet the d**n thermostat in the plug. So there goes your therory...... DEWFPO <{POST_SNAPBACK}> Dewfpo- Unless the factory is just installing one block heater instead of block specific heaters... Beasley- I could do that, but if operating your heater in my block does not harm anything...I would probably just lop off the plug on my factory heaters and install a heavy one from a hardware store...It would probably work, but again, I'm concerned about harming something and thus the reasoning behind GM's wonderful decision to outfit these trucks as such... GM TECH- you are absolutely right...this industry is no different than any other...quality answers are tuff to come by whether you're buying carpet or a light switch...it's about finding the right people at the right time...I certainly agree, I guess I'm just looking too hard for that one person who has some insight as to why this is... Does anyone have access to a parts sheet to determine if the p/n is different for heaters from say 2002 and 2005 or 2006? Again...if I go in to buy one from the dealer, as in Beasleys case, what numbers are they finding to order the part? Are there notes or *'s citing that certain yeared vehicles must have the thermo equipped plug? If not, what would stop a part guy from handing out a clean plug to an 06 owner?...would not make it right and certainly a good arguement when something goes wrong..."not my fault...this is the heater you guys sold me," but if there are no notes for the differing heaters, this has to happening somewhere...

Another thought as I sit here lamenting the useless heaters in my trucks... with GM cutting back on stuff to save money (wire gauges, engine comp light, glove box light...) perhaps they reduced the gauge of the wire for the heater however due to the significant draw, there was a problem with melting wires...instead of fixing this, they put the thermostat on to avoid the use above 0F, allowing the cold <0 temps to cool the wiring...

A couple of things...Beasley is in the ? range with a 2003...that p/n may not necessitate the thermostat-plugged heater...like i said before...95, 99 and 02 did not have the thermostat, but the 05 and 06 do...i don't know when the thermostat began to be installed... As far as the picture...different plug, both of mine are black with a circular "tumor" (a bit larger than a hearing aid battery) behind the plug. Theres no question about the existence of the thermostat...if someone's heater is working intermittently, there is something wrong with that heater or the testing procedure... As far as the Partech guy...first have him refer to the owners manual that states there is a thermostat which will not allow the heater to operate above 0 F and then ask him about it...perhaps he won't deny its existence again, how can there not be someone at GM with the answer as to why this is...And from the posts, in addition to my own experiences, why when you as several people, who are supposed to be professionals in this business, do you get several different answers to the same question? Just a thought from another forum...the combination of metal (block heater) and aluminum (block) causes corrosion when electicity is introduced via the heater...therefore, GM lowered the operable temperature thus greatly reducing the use of the heater and as a result, greatly reduced the potential problems from the corrosion issue... sounds crazy, but its alot better than the stupid looks i get when i ask someone at the dealer about the thermostat