Problem with my 2003 Pontiac Grand Prix
3.4L V-6
Check Engine Soon
codes = p0128
work done prior = Recently had engine cooling system flushed and coolant
replaced
work done to repair = None so far
tech = JK
question = Just as my car turned over on 170,000 the check engine light
came on. I had Auto Zone check code. Came up p0128. Light stayed on
for about 50 miles then went off. Any ideas as to what this might be...or
should I just leave it alone until it comes on again? Why does this come on.
Thanks a bunch...
JK:
Thank you for the tip/donation.
This code is described as 'coolant temp. below thermostat regulating temp or
threshold' A common cause for this code is a sticking thermostat. The coolant
temp is too low for longer than the pcm(computer) expects. It is possible that there
was an air pocket in the system after the flush and that caused the code. Keep an
eye out for the light to come back on, coolant temp gauge (if you have one) to stay
low, poor heat from heater/ac system, or coolant fans under the hood stay on with
car off. If some of these things occur, then have your thermostat changed, and
make sure the system is bled of air after re-filling the coolant.
3.4L V-6
Check Engine Soon
codes = p0128
work done prior = Recently had engine cooling system flushed and coolant
replaced
work done to repair = None so far
tech = JK
question = Just as my car turned over on 170,000 the check engine light
came on. I had Auto Zone check code. Came up p0128. Light stayed on
for about 50 miles then went off. Any ideas as to what this might be...or
should I just leave it alone until it comes on again? Why does this come on.
Thanks a bunch...
JK:
Thank you for the tip/donation.
This code is described as 'coolant temp. below thermostat regulating temp or
threshold' A common cause for this code is a sticking thermostat. The coolant
temp is too low for longer than the pcm(computer) expects. It is possible that there
was an air pocket in the system after the flush and that caused the code. Keep an
eye out for the light to come back on, coolant temp gauge (if you have one) to stay
low, poor heat from heater/ac system, or coolant fans under the hood stay on with
car off. If some of these things occur, then have your thermostat changed, and
make sure the system is bled of air after re-filling the coolant.
WARNING LIGHTS
OBDII Code P0128 Coolant Temperature
Other related articles:
2000 Pontiac Grand Prix 3.8 V6.
Repairs for this problem: Heater core flushed, hoses all checked all warm-no blockage, thermostat
changed-radiator checked-cap replaced-
Question = I have a 2000 pontiac grand prix GT-- I all of a sudden have nothing but lukewarm heat at best
blowing. Also my car always runs at 210 but now doesnt get even close to that. We replaced the thermostat,
had the radiator checked and cap replaced. The heatercore has been flushed and hoses checked all fine.
My husband said it heats up when sitting, but as soon as I drive it, well the temp goes down. My husband has
checked everything he could think of with the heating system. Can anyone offer any suggestions? Im one
step away from taking it to the dealer. Which Im sure will cost me a bundle! Please help!
Repairs for this problem: Heater core flushed, hoses all checked all warm-no blockage, thermostat
changed-radiator checked-cap replaced-
Question = I have a 2000 pontiac grand prix GT-- I all of a sudden have nothing but lukewarm heat at best
blowing. Also my car always runs at 210 but now doesnt get even close to that. We replaced the thermostat,
had the radiator checked and cap replaced. The heatercore has been flushed and hoses checked all fine.
My husband said it heats up when sitting, but as soon as I drive it, well the temp goes down. My husband has
checked everything he could think of with the heating system. Can anyone offer any suggestions? Im one
step away from taking it to the dealer. Which Im sure will cost me a bundle! Please help!
Answer: You need to make sure there is not an air pocket in the cooling
system. That will cause the temperature to be erratic. Also, are you sure you
installed the correct thermostat? If it is incorrect or staying open all the time
the car will not heat up to operating temperature and you won't get much
heat from the vents. You probably do not have a radiator, heater core, or
hose problem since the coolant temp is not getting to 210 like it used to. It
sounds like a thermostat issue, so I'd double check that to start with.
system. That will cause the temperature to be erratic. Also, are you sure you
installed the correct thermostat? If it is incorrect or staying open all the time
the car will not heat up to operating temperature and you won't get much
heat from the vents. You probably do not have a radiator, heater core, or
hose problem since the coolant temp is not getting to 210 like it used to. It
sounds like a thermostat issue, so I'd double check that to start with.
| 12-9-10 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. |
Comments
| 2-27-11 I have the same problem with my car no heat and runs at 40 degrees could it be plugged heater core? |
| If you mean the engine temperature is running at 40 degree, then the thermostat is stuck open ans needs to be replaced. |
| 3-15-11 It is your ccolant temp switch and I bet your fans run all the time also, it is located below thermostat housing. |
| 5-31-11 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 tempature sensor. Still the light is on. I cant get my car to pass the inspection even to its running great. |
| 6-1-11 There may be a service bulletin or computer update for your problem. Check with the Dealer. |
| 8-26-11 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... |
