What the P0453 code means
A P0453 code means that a reading from the engine’s evaporative pressure sensor is higher than normal, indicating changes in pressure that are out of factory specification.
What causes the P0453 code?
Modern emissions systems include an EVAP canister which allows fuel tank vapors to be collected and purged back into the engine, where they can be burnt rather than expelled into the atmosphere. EVAP systems feature a pressure sensor that monitors the system’s integrity, and at regular intervals the EVAP system performs a pressure test on itself, checking that there are no leaks in the system. In a P4053 code instance, the EVAP sensor or fuel tank pressure (FTP) sensor is sending information to the PCM that indicates a higher than normal pressure in the EVAP system. Please note that on some vehicles, the FTP is incorporated into the electric fuel pump assembly in the tank.
What are the symptoms of the P0453 code?
Other than a hard code and illuminated malfunction indicator light (MIL), the only other symptom might be a noticeable smell of raw fuel.
How does a mechanic diagnose the P045 code?
With key on/engine off, use a scan tool to retrieve the code from the engine’s diagnostic connector. Pay close attention to fuel tank pressure readings, using a scan tool.
Normal voltages should be around 2.5 volts, and should never exceed 4.5 volts. A reading of around 2.7V with the gas cap off might indicate an intermittent problem.
Use a digital volt/ohmmeter to measure voltage at the signal wire while wiggle-testing wiring at the FTP sensor. A fluctuation in voltage during the wiggle-test could point to connector problems such as broken wiring, corrosion or dampness.
If the scan tool shows voltages above 4.5V, unplug the sensor (if possible) and recheck the voltage. If voltage is still high with the sensor unplugged, inspect the wiring harness for a short on the signal wire. If high voltage disappears when the sensor is unplugged, check for the sensor’s ground and for proper reference voltage supplying the sensor.
If the sensor has a good ground and 5V reference voltage, it’s likely that the sensor itself has failed and needs to be replaced.
The pressure sensor can also be tested with a vacuum gauge while connected to the wiring harness, as you observe the data stream’s change on a scan tool.
If after replacing the sensor and all test results are within spec, the problem might be with the PCM itself. Remember that failed PCMs are rare and replacing the PCM will require complete reprogramming.
Common mistakes when diagnosing the P0453 code
Technicians often misinterpret the P0453 code to mean problems with the fuel cap, evaporative purge valve or evaporative vent valve.
How serious is the P0453 code?
A P0453 code may not cause any problems in drivability or fuel economy, but is likely to cause your vehicle to fail a state-mandated emissions test.
What repairs can fix the P0453 code?
- Repair or replacement of wiring
- Repair or replacement of connections
- Checking EVAP pressure sensor and/or FTP sensor.
Additional comments for consideration regarding the P0453 code
For a hard code to register, the EVAP monitor test must present a fault on two consecutive cold starts and drives.
Need help with a P0453 code?
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