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P0128 check engine light code

72K views 10 replies 7 participants last post by  heat_z0ne 
#1 ·
Hello,

I'm getting a P0128 code on my 2003 V4 Camry. Autozone diagnosis says it's either
a) coolant low level
b) sensor not working correctly
c) thermostat not working correctly.

As part of 90k mile check about 3500 miles ago, the mechanic replaced the coolant. I didn't check the coolant after he had replaced it but I just checked it today and it's about 1 inch below the full level. Is this normal coolant usage considering that it's been about 3500 miles and 3 months since it was last filled?

If the coolant level is okay, then how do I figure out if it's the sensor/thermostat?

Thanks,
Kunal
 
#2 · (Edited)
Hello,

I'm getting a P0128 code on my 2003 V4 Camry. Autozone diagnosis says it's either
a) coolant low level
b) sensor not working correctly
c) thermostat not working correctly.

As part of 90k mile check about 3500 miles ago, the mechanic replaced the coolant. I didn't check the coolant after he had replaced it but I just checked it today and it's about 1 inch below the full level. Is this normal coolant usage considering that it's been about 3500 miles and 3 months since it was last filled?

If the coolant level is okay, then how do I figure out if it's the sensor/thermostat?

Thanks,
Kunal
Code P0128 means that the coolant temperature is below the thermostat regulating temperature.

I doubt that you actually used coolant. I'm guessing that there was an air pocket in the system. Fill the coolant to the proper level and check for leaks. What is your engine/coolant temperature?

If the temperature is ACTUALLY low, you will need a new thermostat. If the temperature is ACTUALLY normal but the sensor shows it's low, you need a new sensor.

I'd start with filling the coolant up and clearing the code.

By the way. Your car is an I4 (inline 4 cylinder), not a V4.

Welcome to TN.

Here's cooling system link for you: http://www.camrystuff.com/manuals/Gen5/16_Cooling.pdf

EDIT: Note that the problem could be something else also. It could be a faulty ECM (computer), wiring, etc.
 
#3 ·
To add to TRD's explaination:

DTC P0128 COOLANT THERMOSTAT (COOLANT TEMPERATURE BELOW THERMOSTAT REGULATING TEMPERATURE)

CIRCUIT DESCRIPTION

DTC Detecting Condition


HINT:
This is the procedure of thermostat.

If the engine coolant temperature becomes less than 75 °C (167 °F) , it is abnormal.

If not due to the thermostat malfunction, it is abnormal.

Step 1 - 2

INSPECTION PROCEDURE

HINT: Read freeze frame data using the hand-held tester or the OBD II scan tool, as freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was
 
#11 · (Edited)
I had P0128 and P0128 (pd) code on 2001 camry with only 55k miles, check temperature gauge shows low up to long time and when i drive in traffic was showing normal, decided to change thermostat with OEM, Got from dealer for $28 + $6 for seal. just open it to see thermostat ,is leaking from side. The shaft looks bend. Will tell you after 100 mil driving. cleared code with ODBII.
 
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