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Error Code P0453 is defined as Evaporative Emissions Control System Pressure Sensor High Input. This means there’s a change in pressure value above the specified value of the manufacturer.
This error code is a generic trouble code, meaning it applies to all vehicles equipped with OBD-II, especially vehicles made since 1996 up to present. Specifications on the definition, troubleshooting and repairs of course, vary from one make and/or model to another.
The EVAP (evaporative) system allows fuel tank vapors to be purged into the engine. They are kept from expelling into the atmosphere as harmful emission by being burned. The EVAP system comes with a pressure sensor that regularly checks the integrity of the system.
The EVAP system tests the pressure sensor from time to time to make sure there are no leaks in the system. It utilizes the sensor known as FTP (fuel tank pressure) sensor to look for leaks. Basically, the Error Code P0453 means the PCM (powertrain control module, also known as ECM or engine control module), which is the brain of the engine, determined that the evaporative pressure sensor of the engine shows values higher than normal pressure (more than 4.5V) in the EVAP system, indicating a change in pressure way higher than the factory specifications of the manufacturer. This is caused by fuel tank vapor leaks into the system.
Note: for some vehicles, the FTP is part of the fuel pump assembly tank.
As with most EVAP emission trouble codes the Error Code P0453 don’t come with noticeable symptoms other than the activation of the Check Engine light. In some cases however, they may be noticeable fuel odors (raw fuel) due to released fuel vapors.
There are many reasons and contributory factors for this error code, such as:
- Short to voltage on FTP sensor signal wire
- Open on FTP sensor signal wire
- Defective FTP sensor
- Damaged or loose FTP sensor connector
- Loose of ground to the sensor
- Fuel tank with abnormally high pressure due to clogging in the EVAP purge hoses or overfilled tank
How to Check
With key on/engine off, technicians retrieve the engine’s code through the diagnostic connector using a scant tool. They pay close attention to the readings from the fuel tank pressure using the scan tool.
- The normal voltage is about 2.5V, and should never go higher than 4.5V. A reading with 2.7V with gas cap off, may means intermittent problem.
- Using a digital volt/ohmmeter (DVOM), measure the voltage at the signal wire and wiggle-test the wiring at the FTP sensor. Fluctuations in voltage during wiggle-test could means connector problem, such as corrosion or dampness in the wiring, or broken wiring.
- If the scan tool shows voltage higher than 4.5V, try unplugging the sensor (if possible) and recheck the voltage. If the voltage is still high while the sensor is unplugged, check the wiring harness and look for signs of short on the signal wire. If high voltage disappears when the sensor is unplugged, check the sensor’s ground and for proper reference voltage supply of the sensor.
- If the sensor has a good ground and 5V reference voltage, then there’s a good chance that the cause of the problem is failed sensor. In this case, it must be replaced.
- The pressure sensor can also be tested using a vacuum gauge while connected to the wiring harness, as you can see from the data stream’s change on a scan tool.
- If after sensor replacement all the results are within the specs, that may suggest a problem in the PCM itself. Though quite rare, failed PCM can be a possibility, and must be replacement and reprogrammed.
How to Fix
Repairs for this error code are pretty simple. Some of the easiest and most common fixes are:
- Repair or replacement of damaged wiring
- Repair or replacement of damaged connectors
- Checking the FP sensor and/or EVAP pressure sensor
In many cases, technicians misdiagnose this error code as a fuel cap problem, or problems with the EVAP purge valve or EVAP vent valve. Thus, it is important to conduct a thorough diagnosis before proceeding on repairs.