I'm running into the same problem, keep getting an SES P0128 code, fluid is fine, car only runs at
about 180-181 degrees. Once the code is cleared, temp goes up (weather is rather cold now, hard
telling if this is a factor) to almost 210 when idle, but when driving, drops back to 180-181. Am
leaning to prior mentioned solution, thermostat is stuck in open position, and willing to pay the 8.99
for the 192 OE Thermostat and do a flush of the coolant system to see if this resolves the problem.
I have the same problem with my car no heat and runs at 40 degrees could it be plugged heater
|If you mean the engine temperature is running at 40
degree, then the thermostat is stuck open ans needs to
It is your coolant temp switch and I bet your fans run all the time also, it is located below
any suggestions? I have a 2001 grand prix.. I also have a check engine light with this 0128
code. I have had the thermostat replaced as well as some sort of temperature sensor. Still
the light is on. I cant get my car to pass the inspection even to its running great.
There may be a service bulletin or computer update for your problem. Check with the
My 2003 runs for about ten minutes then stalls out what can be the problem??
|Could be anything from a vacuum leak, an ignition
problem, or most likely a bad crank sensor or ignition
module. Any of these would need some diagnosing by a
qualified technician. Best of luck...
My 02 Grand Prix runs hot had new radiator thermostat and water pump car still running hot and
heater blows cold often and occasionally it will blow hot air. What's the problem?
|Could be an internal engine problem such as a cracked
cylinder head gasket. Usually it's a bad sign when you
have no heat, or it only blows hot occasionally. A shop
can do a cylinder leak down test to find out what actually
is the problem.
Help! My 2000 Pontiac Grand Prix GT chocked and stalled out, would not re-start. I got P0128
code. Will this code prevent engine from starting or there is other problems??
|No, this code will not prevent your car from starting.
|My 2003 pontiac grand prix gt temp gauge goes past half while sitting but goes down as i drive it.
There is no smoke or lights on. What could be the problem?
|Check for a restricted radiator or low coolant level.
|I had the same code on my 2005 and it was the ECT (engine coolant temperature) sensor.
|Hello, I have a 2008 Envoy 4200 Vortec. The Temp gauge in side reads 100 F° all the time. The
A/C Compressor does not come on, But, the fan runs. Is this a bad coolant sensor ?? Can I check it
with a ohm meter, if so what resistance should I see at room temp. I am in Arizona so room temp will
be a little higher... Thanks for your help.
|Yes, it does sound like the temperature sensor. Just tap
on it with a screw driver and watch to see if the gauge
|My 2003 pontiac grand prix gt doesn't goes into reverse and I can't get a reading to find the code,
what needs to be replace?
|If you dont have reverse, it is not something electrical.
There is an internal problem in the transmission.
|I have a 2008 grand prix. The code I also got was PO 128 but my temp gauge is reading normal
and I have hot air. How do I get this light and code to reset?
|Change the thermostat.
|How much would this cost to replace the thermostat on a 2007 Pontiac Grand Prix?
|Cost is approximately 1 hour labor.