What is a code p1258 on chevy equinox

Check the thermostat and replace.

Did you check the fuses, any voltage at the fuses? In the picture, the left side of relay is control, the pcm grounds the control side of relay. Any applicable trouble codes? Check the coolant temp sensor. I'm not saying replace anything. Will the fans come on if you turn on the ac?
The fans should come on around 220 degrees F. Some makes and models, if you unplug the coolant temp sensor, the fan/s may run all the time? The info I looked at was for 1500--5.3L engine--non-hybrid.

P1258 CHEVROLET - Engine Coolant Overtemperature Protection Mode Active https://www.autocodes.com/p1258_chevrolet.html

Follow the upper radiator hose back to the engine. It will clamp to the thermostat housing. Follow the housing back where it bolts to the lower intake. Look a little further back on the intake and you will see it.

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could be a thermostat, head gasket , not fill properly,
P1258 is: engine overtemperature protection, or low coolant fuel disable

You get a reduced power message ? Your vehicle has electronic throttle control or also known as drive by wire . Your gas pedal is electrically hooked to the PCM - engine computer . Has two position sensors inside as does the throttle body on the engine . Over time these position sensors wear an cause improper signals to the computer an the computer will put the vehicle into a limp mode . Most cases it will drive but only at about 20 mph . There are videos on youtube showing how this works , how to diagnose etc....
This P0449 is something different , has to do with the Evap. emissions .
DTC P0449 Evaporative Emission (EVAP) vent Solenoid Control Circuit . Planty of videos on youtube for GM trucks on this problem .
DTC P1516 Throttle Actuator Control (TAC) Module Throttle Actuator Position Performance
The predicted throttle position (TP) is compared to the actual throttle position. The two values should be within a calibrated range of each other. Both the powertrain control module (PCM) and the throttle actuator control (TAC) module redundantly monitor the predicted and actual throttle position. DTC P1516 sets if the PCM detects an out of range condition between the predicted and the actual throttle position.
Look's like you have three different problems , Thought p1516 an p1258 were going to point to same electronic throttle problem .

P1258
Engine Coolant Overtemperature - Protection Mode Active
PCM
DTC P1258

Circuit Description
The powertrain control module (PCM) uses the ECT sensor to monitor the engine for an over temperature condition. This condition occurs when the coolant temperature is above 132°C (270°F). When an over temperature condition is present, DTC P1258 will set. The PCM will disable two groups of four cylinders by turning OFF the fuel injectors. By switching between the 2 groups of cylinders, the PCM is able to reduce the temperature of the coolant.

Check the engine cooling fans for proper operation.
Are the engine cooling fans operative? Have you ever had the thermostat changed ? Is the coolant full ?

Check out youtube videos ! Just type your codes into the search bar .

DTC P1258: Engine Coolant Over-Temperature Protection

The powertrain control module (PCM) has the ability to disable 4 injectors during an engine over-temperature (overheating) conditoin. Engine is considered over-temperature whenever the engine coolant temperature reaches 268 F. This protection mode allows the PCM to alternate between groups of cylinders, thereby reducing coolant temperature. This is accomplished by disabling the fuel injectors. This DTC is set to show that an overheating condition was or is observed by the PCM and that the protection mode has been engaged.

You will need to inspect the cooling system to see what is causing your overheating issue. If the engine is not actually overheating, this code may be set due to a faulty engine coolant temperature (ECT) sensor.

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P0741....Torque Converter Clutch Circuit Performance or Stuck Off
P1258 Engine Coolant Overtemperature - Protection Mode Active
the first code is a generic code the latter code is a GM code and if this is correct the engine shut down because it was overheating for whatever reason or the sensor is faulty

Trouble Code: P1258 (4.6L V8 VIN 9 Auto)
Engine Metal Over-Temperature Protection
Number of Trips to Set Code: 1
OBD II Monitor Type: CCM Details
Indicators: MIL Details

• CCM Details
• MIL Details

Trouble Code Conditions:
DTC P0117, P0118 and P0125 not set, Engine started; and the PCM detected the ECT sensor indicated more than 270ºF for 10 seconds. The PCM uses the ECT sensor to detect if the engine is running too hot (when the ECT sensor is over 268ºF). If the engine is overheated, DTC P1258 will set. The PCM will disable 2 groups of four cylinders by turning off the fuel injectors. By switching between the two groups of cylinders, the PCM is able to reduce the temperature of the coolant and lower the temperature.

Possible Causes:

• Engine cooling system problem (test the cooling fan operation)
  
• Engine coolant level is low or the mixture is not correct
  
• ECT sensor is out-of-calibration or "skewed"
  

2003 chev silverado truck 5.3 code p1258 the truck over heated and shut down can someone help me please