Threw a P0128

[Eagle]

Why suddenly would my car start doing this?

DTC P0128
Circuit Description
An engine coolant temperature (ECT) sensor monitors the temperature of the coolant. This input is used by the powertrain control module (PCM) for engine control and as an enabling criteria for some diagnostics.

The air flow coming into the engine is accumulated and used to determine if the vehicle has been driven within the conditions that would allow the engine coolant to heat up normally to the thermostat regulating temperature. If the coolant temperature does not increase normally or does not reach the regulating temperature of the thermostat, the diagnostics that use ECT as enabling criteria may not run when expected.

This DTC will only run once per ignition cycle within the enabling conditions. If the PCM detects the calibrated amount of air flow and engine run time have been met, and the ECT has not met the minimum thermostat regulating temperature, DTC P0128 sets.

Conditions for Running the DTC
DTCs P0101, P0102, P0103, P0112, P0113, P0116, P0117, P0118, P0125, P0502, P0503 are not present.
The startup ECT is less than 75°C (167°F).
The intake air temperature (IAT) is more than -7°C (+19°F).
The engine run time is between 30-1,800 seconds.
The vehicle is driven more than 0.8 kilometers (0.5 miles) at more than 8 km/h (5 mph).
Conditions for Setting the DTC
The PCM detects that:

The calibrated amount of engine run time has been met.
The calibrated amount of engine air flow has been met.
The calibrated vehicle speed and distance have been met.
The calibrated ECT of 80°C (176°F) has not been met.




IN OTHER WORDS, BAD T-STAT OR ENGINE COOLANT TEMP SENSOR

[K J]

whats your temps doin

[TommyGloves]

What t-stat (deg) do you have installed? Like KJ said...what are your temps doing?

[Stink Star Productions]

if it were a ECT sensor it would throw a over/under voltage code 99% of the time.... i would suspect a stuck open thermostat, as that usually fixes this code.....

[Eagle]

Temps seem fine, car still makes fine and good heat... its a 180* AFAIK

[TommyGloves]

Did you recently change the fan settings or are you running stock? Can you get a scan with ETC?

FWIW - I get this code on my SSEi once it gets cold out so I swap out my 180* for the 195*.

I've got an extra 195 t-stat (used) if you want it. (just come pick it up.) LMK

[Eagle]

I havent changed anything and it just started doing this over the past 2 days or so

[02SSEi]

I run a drilled 180 year round with no problem. Car hardly ever gets up to operating temps either. No codes.

[firemandan1700]

i never got this code until i put headers on my car. like it has anything to do with it anyways.

i just ignore it.

[phat_ridegt]

more than likely its been a co-incidence that you never got a 128 code before with a 180 stat....

it could be sticking open...but just clear it with your tuner...nothing to worry about if your temp gauge works

[02BlueGT]

Originally Posted by firemandan1700

i never got this code until i put headers on my car. like it has anything to do with it anyways.

i just ignore it.

The ECT is very close to the exhaust, a badly routed, or just too close to the sensor setup could cause ECT problems

[firemandan1700]

Originally Posted by 02BlueGT

The ECT is very close to the exhaust, a badly routed, or just too close to the sensor setup could cause ECT problems

i made sure my gauge is constant with my scans and it does