04 buick century with P0455 code. mechanic says replace fuel tank pressure sensor. Where is the sensor and how do I replace it myself. Also read it could be a bad gas cap. The sendors (AC delco 16238399) are 50.00 on line. shop wants 250 parts and labor. Can you reset the check engine light yourself after you have done the reapir? Also read to turn ingnition key on and off 15 times to reset computer.
The coolant level sensor is located on the radiator. If you are looking at the engine from the front of the car it will be on the left side. There will some kind of clip holding it in the radiator. Removed the clip and pull the sensor out. You will lose coolant so try to swap it out quick or drain some of the coolant out. Once new sensor is installed, install clip to keep the sensor in place and reconnect the wires to the sensor. Crank the engine and make sure the coolant level is full. This should correct your problem.
You will need to have a reputable mechanic do a diagnostic check on the car to determine the problem. This should pull up a code number in your car's computer and help point the mechanic and you in the direction of the malfunctioning part/s.
Just today, I had a diagnostic check done on mine for nearly $45.00. The mechanic was able to figure out the reason why my service engine light was staying on. I knew my car's radiator fans failed to run when car's engine was hot except when the A/C was running. I had changed out the sensors and was never able to get the light to go out or get the fans working. They were able to determine that the 25 amp fuse for the fans located under the hood was blown. After replacing it, the fans worked as they should, my car runs cooler and the engine service engine light is now out. Of course there are many possible reasons why the service engine light may come on including problems with the car's emissions. A reputable mechanic can solve your problem.
You're either looking at a short in the wire that goes to the fuel sender, or a bad fuel sender. If it was just a broken wire, it would read empty instead. The fuel sender is a permanent part of the fuel pump, so that has to be replaced as a unit.
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HCs (Hydrocarbons): Unburned droplets of raw fuel that smell, affect breathing, and contribute to smog
The evaporative control (EVAP) system captures any raw fuel evaporating from the fuel storage system (e.g. the fuel tank, filler neck, and fuel cap). Under precise operating conditions-dictated by engine temperature, speed, and load-the EVAP system stores and purges these captured fuel vapors back into the combustion process.
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The EVAP system is designed not only to capture, store, and purge any raw fuel vapors that leak from areas in the Fuel Storage system, but also to run a series of self-tests that confirm or deny the operational and vapor holding ability of the system. This is an important task because at least 20 percent of vehicle-produced air pollution originates from malfunctioning Vehicle Fuel Storage systems.
There are many ways to "leak test" the EVAP system, but most perform the leak test when the vehicle is sitting (like over night) or during the initial start-up after the vehicle has been sitting over night. The EVAP system's operational performance is also tracked by the Powertrain Computer by reading the change in the oxygen sensor voltages and short term fuel trim whenever the stored vapors are released or "purged" back into the combustion process. These values should indicate that fuel is being added to the system and that the overall mixture is getting richer. The purging process occurs when the vehicle is under acceleration, which is when most vehicles require additional fuel.
P0455 Diagnostic Theory for Shops and Technicians
The P0455 code indicates that there is a large leak in the EVAP system, but this is somewhat misleading. What the code really indicates is that the EVAP system will not create a significant vacuum when it performs its leak test, as monitored by the Fuel Tank Pressure Sensor.
Here is how the evaporative leak test is performed by the Powertrain Computer:
When the leak test is performed, the vehicle must have been sitting for at least four to eight hours so that the engine temperature and outside air temperature are identical. There must also be between 15 and 85 percent fuel in the tank-this is to provide a baseline for the test since gasoline and diesel are volatile fluids that expand and vaporize easily with warm temperatures.
When the leak test initiates, the Vapor Canister Vent Valve is closed to prevent any fresh air from entering the EVAP system.
The Purge Valve is opened, which allows the engine to create a vacuum in the EVAP system.
After a specified time interval-usually about ten seconds-the Purge Valve is shut off and the vacuum level in the system is measured by the Fuel Tank Pressure Sensor.
Finally, a countdown initiates, which measures the rate at which the vacuum decays in the system. If the vacuum decays much faster than the specified rate or if no amount of vacuum is reached on two consecutive tests, then the Powertrain Computer will fail the EVAP system for a gross leak and trigger the P0455 code.
Common Tests for the Evaporative System
The P0455 code is somewhat misleading because the problem may not be a large/gross leak at all. Many systems trigger this code if there is no EVAP flow detected, which is tracked by changes in Short Term Fuel Trim and Fuel Tank Pressure Sensor data. For example, if the Purge Valve is shorted and never closes, it can trigger a P0455. Be ready to think outside of the box when tracking down the cause of a P0455.
Retrieve the code and write down the freeze frame information to be used as a baseline to test and verify any repair.
Perform a pressurized smoke test. During the test, perform a careful and close examination of the visible hoses, fuel filler neck, installed filler cap, fuel tank, vent valve, purge valve, and vapor holding canister. Open the Throttle Body to make sure there isn't an internal leak that is flowing smoke into the intake manifold. (Be sure to close off the vent valve during the smoke test! If possible, use tape so you don't overwork the electrical portion of the Vent Solenoid by having it energized for too long.)
Run an additional smoke test while using the scan tool live data stream feature with the Fuel Tank Pressure Sensor PID in plain view. As the test inserts smoke into the fuel storage system, the Fuel Tank Pressure readings should increase. If the pressure readings do not increase, the system will think that no pressure or vacuum is being created when the EVAP monitor is performed when, in fact, there is a pressure/vacuum being created that Fuel Tank Pressure Sensor is unable to read. The Fuel Tank Pressure Sensor is the primary feedback sensor that the Powertrain Computer relies on for the leak test data each time the EVAP monitor is run.
Inspect and test the fuel cap to determine how well it fits onto the Fuel Tank Filler Neck. If the cap will not seal or hold vacuum/pressure, then it can trigger the P0455 code.
Verify that the Purge Valve and the Vent Valve work properly and hold vacuum for a sustained amount of time-at least thirty to sixty seconds. If either one of these valves function improperly, the system will not develop and/or hold the proper amount of vacuum. You may have to remove and bench test them. Also be sure to measure the electrical resistance of the solenoids to be sure they are in spec.
If all the components seem to function properly, then perform another smoke test of the entire EVAP system, but this time, use your sense of smell. Go around the entire system to see if you can smell any fuel odor. In some cases, the smoke will exit in a manner that is invisible, but there will be evidence of a fuel odor that will lead you to the problem area. This area may be completely hidden by the frame, fuel tank, etc.
If all tests fail, clear all the codes and perform a drive cycle test drive to make sure that the code re-sets are what are the freeze frame data points are referring to.
Same 3 codes , p0455, p0442, & p2138 on my 2009 Chevy Impala and brought the car to a General Motor or Buick Dealer Service Department to replace vent solenoid or solenoid fuel tank evaporator control . Also replaced gas pedal position sensor.
FUEL PRESSURE SENSOR IS PART OF THE EVAPORATIVE EMISSION CONTROL. SYSTEM IT SITS ON TOP OF FUEL TANK.MONITORS GAS PRESSURE IN FUEL TANK.YOU NEED TO FIX CAR WILL FAIL EMISSION TEST AND FAIL STATE INSPECTION.
If you mean the fuel level sender for the gauge it is part of the fuel pump module inside of the fuel tank. If you mean the fuel tank pressure sensor for the EVAP emission system it is located on top of the fuel pump module on the outside/top of the tank. If you have an erratic fuel gauge then the sender is most likely at fault. Some are serviced seperately but some are sold only as part of the pump. If you have to remove the tank and pump to replace the sender and have close to 100k on the odometer then I would STRONGLY suggest replacing the fuel pump at that time.
Possibly the EGR valve or TPS sensor if you have CEL codes. Check fuel pressure and if low change fuel filter if it is still low replace the fuel pump I beleive it is suppossed to be 41 to 47 psi. Pretty easy to replace fuel filter the Buick Century has a cover you remove in the trunk to access the fuel pump making the change very easy, if you can fit in the cramped space of the trunk.