HPT Thermostat question

[Dainslaif]

So, my car recently started throwing
P0128 - "Coolant Thermostat (Coolant Temp Below Thermostat Regulating Temperature)"

Which has a TSB out for it - TSB#05-06-04-038D

My question is - in an attempt to avoid paying a dealer $95 to reflash the PCM (they want $45 for a 'diagnostic fee' on top of a flash, which runs $50), is there a temperature setting in HPT that's adjustable, and if so, does anyone know if it would be as simple as lowering the threshold temperature in HPT?

Thanks.

[hammers]

is your car under warry

[Dainslaif]

If it was under warranty, I wouldn't have to pay for a busted thermostat or a TSB, would I? ;o

Short answer: No.

[ionredline05]

When most redline come in the shop with po128 I have found the ECT sensor bad and replace them. They have not came back.

[Dainslaif]

The ECT sensor controls the temp needle in the console, right? That seems to be performing normally as far as I can tell. My mechanic friend from Chevy says if the ECT went bad the car would be running way worse than it is.

Either way it's only a $20 part. If a mod could move this to troubleshooting that'd be fine with me, since that's what the thread turned into.

[ionredline05]

The ECT dosnt operate the gauge it sends the temp to the ECM and it compaires it to what the ECM has set for operating temps if it sends a reading lower then what is set in the ECM then it set the p0128 code. The ECT is at the upper radiator hose very easy to get to and very little coolant comes out.

[Dainslaif]

Well, aside from the possibility of my car never having been hit with the PCM reflash, Sunburst (my Chevy mechanic with an SS) tells me if the ECT is acting up, the car would drive like shit. So far the only thing I've been seeing is the P0128 and P0172 (rich system - likely caused by the P0128). Aside from those, the car runs fine.

I'll just rep the thermo and see if it comes back, if it does I'll probably have to visit Saturn since the car isn't acting up at all.

[raptors_67]

you could just delete the code with HPT... or at least not have it throw the CEL when it does come up.

[Dainslaif]

I'd rather fix it, since it's causing my engine to run rich.

[06blackg85ss]

I'm throwing the same code, but my car is running rediculously cold, temp won't go more tha 100 degrees over outside temp (i.e. it's 21 degrees outsidem I get to a max of 121 when driving) I think either my thermostat is stuck open, or maybe that's the issue, but I do know I don't get heat for a long time, so it's definitely not closing the thermostat