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Problems/Service/RepairsIf you have a problem with your HHR, want a tip on repairing or performing a particular service to you HHR here is the place to post!
Apparently it needs to specify Original Equipment and not pro series, but the number is AC Delco 131-158
Having same problem with mine, No temp readout or gauge at times. If the Check Engine light is on, it disables the temp display and gauge. I replaced the sensor and it seems to be working now.. Need more driving to be sure. I ordered a thermostat just in case.
I'm having the same issue with the temp gauge and DIC showing dashes. While mine was out, I hooked up my scantool and discovered the temp sensor was still sending a temperature reading. The ECM likely is programmed to kill the temp reading to alert you to a failing thermostat. I doubt that changing the sensor is going to do anything, for the most part sensors either work or they don't.
Your AC doesn't work either.
Just change the t-stat, stop trying to re invent the wheel. It is the problem 99.9% of the time, the other .01% is a wire is crushed.
Thermostat will not be here for 3 more days!! taking the old one out won't do me any good until the replacement one arrives. I found 4 or 5 more posts under different titles in which changing the sensor fixed the problem so saying it will fix all problems like this might not be the right answer. Working with what I got and what logic tells me. Today I drove about 4 min to a meeting, temp went from 23 degrees to 120. so in theory going from 60 degrees to 180(ish) sounds about right.
Okay, I'm wrong. A few people had the 0.1 % problem or, had a transient fix by replacing the sensor. But, there are hundreds of posts for replacing the t-stat.
I can almost guarantee that when you get around to pulling the t-stat out you will find a piece of rubber holding the valve open.
BTW, it is safe to drive with the code; if it bothers you too much you can run the engine for a couple of minutes then turn it off for 10 minutes then re start; VOILA, no more code because the temp got to 180F fast enough.
I don't know why it is so difficult to understand: If the coolant starts out cold it takes longer to reach a high temp than if it starts out warm. That means that sometimes the code is triggered and sometimes it isn't (intermittent). The sensor only reports the temp, If it reads HIGH there should be no P0128, only if it is slow to respond or reading 0 there will be a code.
The actual name of the P0128 fault is "Engine Coolant Temperature (ECT) Below Thermostat Regulating Temperature". That means that the t-stat is open when it should be closed. The t-stat keeps the temp ABOVE 180F. It OPENS at 180F and stays open until the temp reduces to 179F and then closes (numbers approximate). If the temp gets to about 217F the fan turns on to cool the coolant then it turns off when the temp is back down to 180F and the t-stat closes.
Here is where I work on my HHR. It is up to a whopping 27 degrees outside and we got a slight dusting of snow last night. Thankfully it isn't a foot or two deep like normally at this time of year. Pretty much hit the warmest it will be for at least the next 10 days, This coming weekend should see highs in the 17 to 6 degree range so we got that to look forward to. Still waiting for the thermostat which should arrive in 2 days (??) hopefully we will keep this hot spell which will allow me to go out and wrench before the cold hits (??) They are predicting snow that day so we shall see. Until then, here I sit. Luckily I am not driving to work anymore so that helps too. The wife drives the Trailblazer to work so we have been dumping a lot of money into that with brakes, ties, rotors, wheel bearings, and a rack & pinion (twice in 4 months now) I have the time to check out sensors and wiring (until I get too cold) so that is what I do. Seems like all my problems lately have been the 1%-10% of what happens or the proverbial " wow that never happens"
Not my house in the picture, only parking on one side of the street.
My 07 did the --- F thing again. This time I got pics. As you can see, the coolant temp (ECT- Engine Coolant Temp) is 150.8 degrees, showing that the sensor and associated wiring is functioning.
This is not to say that jimwv doesn't have the .000001% chance of a bad sensor, I'm just pointing out how important it is to have the proper diagnostic tools on computer controlled cars. This ain't the old days when a car would run with only 3 wires. By using a proper tool, you can see that the computer is getting the information, and is turning on the warning because the data is not within normal operating parameters.
I cannot stress this enough- WITHOUT THE RIGHT TOOLS FOR THE JOB, YOU WILL END UP SPENDING MORE TIME AND MONEY THAN IS NECESSARY!
Or just ask us and we’ll tell you what is causing the P0128 code 99 44/100ths of the time.
Jim has his HHR parked perfectly to change out the thermostat. Just those 2 10mm bolts and presto chango!
To be fair and honest, I made a few short trips today, less than 5 miles each. Coolant temp maxed out at 135 degrees, then dropped down to 131 an stayed right around that temp. When I parked, the temp readout went to ___F and shutting off the motor, and restarting, it stayed at ___F. Temp outside is around 26 degrees, and speeds were not much over 30 mph. Heat from the vents was not terribly hot but pretty warm... Thermostat is supposed to arrive tomorrow, along with 2-4 inches of snow.
What I am saying is that All indications are the thermostat and a good chance that I am wrong.
Excuse me while I retreat on my square wheeled bicycle...
01-06-2024, 08:21 AM
