Technical Description of OBD-II Trouble Code
The input from the evaporative emissions control system pressure sensor is too high.
What does that mean?
This diagnostic trouble code (DTC) is a generic powertrain code that applies to vehicles equipped with OBD-II. Although it is a generic code, the specific repair steps may vary depending on the make and model of the vehicle.
The EVAP (Evaporative Emissions) System allows fuel tank vapors to be purged into the engine and burned instead of being released into the atmosphere as harmful emissions. The EVAP system includes a pressure sensor to check the system’s integrity.
Periodically, the EVAP system performs a pressure test to ensure that there are no leaks. It uses a sensor called a fuel tank pressure (FTP) sensor to detect leaks. Essentially, P0453 means that the Powertrain Control Module (PCM) has detected that the EVAP pressure sensor or FTP is indicating a higher than normal pressure (above 4.5 Volts) in the EVAP system. Note: In some vehicles, the FTP is part of the fuel pump assembly in the tank.
Other related trouble codes for evaporative emissions include P0450, P0451, P0452, P0454, P0455, P0456, P0457, P0458, and P0459.
Potential Symptoms
There are usually no noticeable symptoms associated with this code other than the illumination of the Malfunction Indicator Lamp (MIL), commonly known as the Check Engine Light. However, in some cases, there may be noticeable fuel odors.
Causes
A P0453 DTC trouble code may be caused by one or more of the following:
Possible Solutions
Using a scan tool, access the FTP sensor value with the key on and the engine off (KOEO). The normal value is usually around 2.5 Volts at atmospheric pressure (which may fluctuate slightly due to altitude). It should never exceed 4.5 Volts.
1) If the value is close to 2.7V with the gas cap off, the problem is likely intermittent. Use a Digital Volt Ohm Meter to measure the voltage on the signal wire while wiggling the wiring at the FTP sensor to try to induce the problem. If the voltage fluctuates during the wiggle test, check for connector problems such as water in the connector or broken or chafed wiring.
2) If the value shown on the scan tool is above 4.5V, unplug the sensor (if possible) and check the voltage again. If the high voltage is still present when the sensor is unplugged, inspect the wiring harness for a short to voltage on the signal wire. If the high voltage disappears when unplugging the sensor, check for a good ground connection to the sensor and proper reference voltage. If there is a good ground and 5 Volts reference voltage, replace the FTP sensor as it is likely shorted out.
Other EVAP DTCs: P0440 – P0441 – P0442 – P0443 – P0444 – P0445 – P0446 – P0447 – P0448 – P0449 – P0452 – P0455 – P0456
