Getting a low coolant temp code.temp is normal. im

15 is coolant temp sensor reading low temp. 45 is O2 sensor reading rich. Older GM vehicles do react to bad temp readings. I would replace it first. This can cause the rich condition for the O2 sensor.

Well code 125 means the engine is not getting hot enough for the emission system to go into closed loop. So you would check the thermostat first. If the engine is reaching normal operating temp of 195 degrees there could be a problem with one of the O2 sensors or the coolant temp sensor.

The first thing you have not checked is fuel pressure.
The pressure could be low, or the fuel filter could be clogged.
It takes more fuel to run the engine in the first 5 minutes until it warms up than under normal conditions.
The codes mean the sensors are not giving the computer the readings they should, but it does not always mean the sensors are faulty.
If the engine is running rough, or the fuel mixture is lean, the sensors will show that.
Code 44 is O2 sensor reading lean which may be true.
Code 33 is MAP sensor reading low vac which may also be true.
Another possible cause is the coolant temp sensor may not be telling the computer the right thing. If it tells the computer the coolant is 200 degrees and the engine is cold, you won't get enough fuel thru the injectors.

2000 Dodge Dakota idle then dying problem FIXED Atleast my solution

What are the OBDII codes you are getting? If you can give me the codes I can help you out.

Whenever i get this code i like to clear it and see if it returns. Sometimes in extreme cold weather conditions it will set this code and there may not be anything wrong. What motor is in your celica?

DTC - 13 Oxygen sensor circuit open or no activity
DTC - 33 MAP sensor circuit error (signal high indicating low vacuum)
DTC - 54 Fuel pump circuit low voltage

Start with checking the wire leads to the O2 sensors and MAP sensor. Look for any damages to the wire harness and replace any parts damaged or faulty.

The O2 and MAP sensor take reading and sends it to the ECM to recalibrate the fuel injector pulse to adjust the amount of fuel entering the cylinders. When there is an issue to the O2 sensor or MAP sensor and even both, the ECM will be set a a factory default to run rich to keep the engine running and at times the engine may not even run. Normal fuel to air ratio is 14.7:1 - 14.7 air to 1 parts fuel and at default it could be as high as 12.5:1. Good luck and keep me posted, be glad to help you get your truck running 100% again soon and please rate. replacing the thermostat and temperature sensor would also be a good thing since the 4.3 runs best at 190".

try coolant temperature sensor

This code refers to the front oxygen sensor on Bank 1. The heated circuit in the oxygen sensor decreases time needed to enter closed loop. As the O2 heater reaches operating temperature, the oxygen sensor responds by switching according to oxygen content of the exhaust surrounding it. The ECM tracks how long it takes for the oxygen sensor to begin switching. It the ECM determines (based on coolant temp) that too much time elapsed before the oxygen sensor began operating properly, it will set P0135.
Repair short or open or high resistance in wiring harness or harness connectors.
Since you have already changed out your O2 sensor (as long as you used to OEM replacement and not the "Universal" replacement) you should not have to replace it again. You might check your thermostat to part of the time it takes for the O2 sensor to start switching being based on coolant temp, if your thermostat is not operating properly, it could cause the coolant temp to take longer than what is considered by the ECM to be normal.

Chrysler has a bulletin out for a simular condititon that involves replacing the pcm. Heres the bulletin number 18-005-04. This is only 1 possible cause , Fuel pressure, coolant temp sensor, thottle position sensor all can cause like problems. Seeing sensor values and fuel adaptives with a scan tool helps pin point problems.