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code P0128 help

A

ad356

New member
my car is producing a code P0128 not really sure what's going on here. i replaced the coolant temp sensor today. i replaced the sensor because the PCM is reading 160 degrees, but the temp gauge on the dashboard is reading normal about 195. i am reading the PCM data using a ELM 327 cable and a laptop computer. so what gives here? they do not match. also will a pending code P0440. will a pending code prevent my car from passing inspection. the P0128 code is an active DTC. im not looking at putting too much money into the car as its is slowly turning into a salt buggy. im probably going to run it this winter and maybe another winter, then im going to look for another L67 car and i will have a good parts car. i am probably going to look for a regal GS instead of a GTP. i like the GTP but they seem to rot really bad, i have heard better things about the regal GS. at any rate i love the L67 as an engine, it's a decent performing engine although not as fast as my other quick car, a 1996 camaro Z28 LT1, but the LT1 has 2 more cylinders so of course its faster. i only drive the camaro in the summer.

when i look for another L67 car i am looking at southern cars. no way in hell am i going to buy another salted POS. we have the worst cars in the entire country right here in my area. want rusted junk, we have plenty of it rust like you have never seen.

btw the sensor i replaced today is the temp sensor underneath the thermostat housing. could my problem be caused by the thermostat??? the thing is the coolant temp on the dashboard reads normally which tells me that the engine is operating at normal temperature and that the PCM is getting a false reading.
 


try another temp sensor, they are known to bad new in the box. also check the wires to it, they bake in the heat of the cross over pipe and get brittle and crack.
 
i hope that damn thing isnt bad i had a pain in the ass getting that thing out i mean i have done worse things but it's tight there none-the-less. i had to remove the two front bolts on that crosspipe and move it over as far as i could. i thought about trying another thermostat they are cheap but i just dont know if that's the problem. i really dont want to work on this thing anymore then i have to, its kind of rotted underneath, i have better things to work on like my camaro. its not that i dislike the car, i just dont like investing time on something that i know is living on borrowed time. although when this car is done i probably will part it out and keep the drivetrain. whatever i do, my 2nd car will be a 3800 car as long as i can find decent ones. i hate what the salt does to my vehicles and find it depressing to work on a car that i like turning into a pile of junk. i really dont want to look at it too much. im not a fan of too many current run cars

what are the differences between the regal GS and the GTP by the way? do the regal's rust less typically? is there any more room to work with? another option i would consider when that time comes is a nice SSEI, but i dont know that would handle as good. we currently have a really nice 1999 SSE. its a southern car, very clean and we have had it oiled already (rust protection) so hopefully it will be around for a long time. i do know that the GTP handles much better then the SSE. the SSE is a great family car but its not really a canyon carver. my GTP on the other hand handles probably almost as good as my Z28 with the Z28 being better because its RWD
 
oh and this bad out of the box thing is really getting on my nerves, i hate doing the job more then once PERIOD. it pisses me off i have better things to do then do the same job two or three times
 
I thought the P0128 was for the thermostat. I've had that code before, and it was on longer drives when the engine never really warmed up. I also had that code when I forgot I had a drilled thermostat.
 
gp has that sporty look thing going for it, the regal is kinda plain, but the engine is the same. inside you get better seats and a more detailed dic. like actual boost #.

other then looks and the inside, its the same car really. the bonnie is pretty nice tho.


temp sensor should not be that bad, open end wrench should get it removed.

new in the box sucks, but its the truth, everyone who changes the damn thing does it 2 or 3 times till they get a working one. (parts store brands seem to be the worst)

i did a engine swap and took the one from my old engine and re used it. no way i was getting a new one for this very reason.
 


I just bought a new temp sensor for the different lim, if it doesn't work, I'll know why. the old one still works, but the plastic is broken on the bottom part
 
P0128 is almost always a stuck open thermostat from my experience but sounds like you have issues with temp sensor as well.
 
i might just get the damn code turned off, it doesnt seem to effect the way the car runs..... in fact i think im just going to go with the EVAP turned off as well. too much of a headache worrying about EVAP or thermostat codes LOL. none of the other cars i ever owned produced codes for thermostats either the car ran at normal temps or didnt.

my main question about the regal VS. the grand prix...... does the regal have better rocker panes because that's where the GP sucks.

oh, yeah and i do love the bonne. we are on our 3rd bonneville. the last bonneville we had was a 96 SE we bought it for $1,200 put a couple hundred in repairs (harmonic balancer and a couple other things). we drove that car for 3 years and sold it for $700. we bought the SSE because it was just in fantastic shape and low miles for the age. all of the 3800 cars are reliable and at this point cheap, nearly everyone wants new. i do not want new i want reliable and proven. what i want is 3800 reliability not some 1.4 turbocharged torque-less hand granade POS mounted up to a 6 speed POS automatic transmission. at least we know what we are getting when we buy a 3800 car, a proven record of reliability.
 
regals can get rotted out, but because theres no rocker cover, the rockers dont seem to rust up as bad. towers still rot out tho just like a gp.

my regals a 98 and has like 235,000 on it. i can still jack it up via the rockers. rear tower's are showing some rust, but not near rotted yet.
 
If you need a temp sensor and can't reuse your old one, either try and find an AC-Delco one or try and get one from a junkyard.
 


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