Error Code P1456 is described as a Evaporative Emission Control System Leak. This means there’s a leak problem in the EVAP (Evaporative Emission Control System), particularly on the tank side, and the engine’s computer has detected the issue.
Error Code P1456 means there’s a fuel vapor leak problem or lack of purge flow in the in the engine’s EVAP control system, and the computer of your 2012 Chevrolet Colorado 4wd-crew-cab has detected the leak. As with other codes that start with P1xxx, this error code however, is a manufacturer specific code. Thus, the diagnosis and repair for this error code may vary from one brand of 2012 Chevrolet Colorado 4wd-crew-cab to another.
The general idea however is that, the problem is caused by a leak in EVAP system of your 2012 Chevrolet Colorado 4wd-crew-cab, specifically in the fuel tank, which can be a result of missing cap, loose or use of wrong fuel cap, leaks in fuel tank, hoses or tubes.
The job of the EVAP system is to keep fuel vapor from escaping the fuel system. Fuel vapors passes through the routed hoses straight to a charcoal canister for storage. Later, when the engine starts and runs a purge control valve will open and allow the intake vacuum to drain off the fuel vapors into the engine.
The EVAP captures any raw fuel that evaporates from the fuel storage (fuel cap, fuel tank, and filler cap). These captured fuel vapors are sent back to the combustion process by the EVAP system, under precise operating conditions, which is dictated by the speed, load and temperature of the engine.
Unburned drops of raw fuel are harmful for health and the environment as it can cause breathing problems and contribute to smog.
What the code actually indicates is that, your 2012 Chevrolet Colorado 4wd-crew-cab’s EVAP system will not make a significant vacuum when it does its leak test, as monitored by the Fuel Tank Pressure Sensor.
Here’s how the PCM conduct the EVAP leak test.
When diagnosing your 2012 Chevrolet Colorado 4wd-crew-cab for this error code, it is imperative that the EVAP system is completely sealed, along with the most common components that may have leaks, such as the gas cap, vent valve, purge valve, hoses and connectors.
First Test – The very first thing you need to inspect is the gas cap. Check whether it is placed right. If it is left open or loosely placed, then close it tight and check whether the ‘Check Engine’ light disappeared after a few drives.
Sometimes, the problem is in the gas cap itself. Take a closer look at your gas cap and look for signs of wear and tear, including the rubber gasket. If you see obvious signs of damage, then it is time to replace them with a new one.
Second Test – If there are no signs of damages in the gas cap, then there might be a leak in the EVAP system. This is where you will need the advance scan tool and other testing equipment, such as the ‘smoke machine.’ The smoke machine detects leaks by pushing smoke through the system. This smoke will exit through holes and leaks, helping you visually detect the leak. Obviously, this is where you may need the help of a professional mechanic, which means you need to take your 2012 Chevrolet Colorado 4wd-crew-cab to his shop for a thorough diagnosis (such as smoke test) and professional repair.
Your mechanic will run a smoke test along with a scan tool with live data stream feature to the Fuel Tank Pressure Sensor PID. They will also conduct a smoke test on the entire EVAP system, and check for fuel odor.
Here are some of the most common ways to repair your 2012 Chevrolet Colorado 4wd-crew-cab from this Error Code:
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