P0453 Code Symptoms and Causes | How to Fix P0453?

Modern enhanced evaporative emissions (EVAP) systems have a monitor that performs system self-tests. That monitor seals the system, then checks for leaks and adequate purge flow. If the fuel tank pressure (FTP) sensor assigned to watch the system sends a signal with a much higher voltage than normal, the engine’s computer may set a P0453 code. This article explains the causes and symptoms of the trouble code P0453.

P0453 Code Definition

Diagnostic Trouble Code (DTC) P0453 stands for “Evaporative Emission System Pressure Sensor/Switch High.”

What does the P0453 Code Mean?

A P0453 code means that the reading from the evaporative pressure sensor of the engine is higher than normal, indicating changes in pressure that are out of programmed specification.

P0453 Code

 The FTP sensor (also known as the EVAP pressure sensor) is usually located on or inside the fuel tank. It measures the pressure (and, therefore, the vacuum) inside the tank.

A code P0453 tells you there’s a problem with this system. More specifically, it’s telling you that the reading the PCM is getting from this sensor is too high and is out of the allowable specifications.

EVAP System Function

The main function of the evaporative system is to prevent fuel vapors from escaping into the atmosphere.

EVAP System

Fuel vapors are carried through a hose to a special charcoal canister filled with a fibrous material, and periodically, an engine vacuum will be applied through the canister purge solenoid to draw atmosphere through the canister, carrying the trapped vapors into the intake manifold where they travel to the combustion chamber as part of the air-fuel mix.

The ECM/PCM’s algorithms factor this small amount of fuel vapor in while calculating the mix because it does make a difference. Engineers refer to the times when canister purge isn’t happening as “purge-free cells” for that reason.

Initially, EVAP systems only purged vapors from the canister while the vehicle was above idle, but with the birth of OBD2 enhanced EVAP systems in the late ‘90s, the canister purge valve may operate at idle. This is important to know because if you pack your gas tank, you might get some liquid fuel in the canister, which can cause an unexpected stumble and then surge at idle as unexpected amounts of heavy vapor or liquid are delivered to the intake.

Symptoms of P0453 Code

 The check engine light is typically the only noticeable condition if you have a code P0453. Sometimes you’ll be able to detect an odor of fuel coming from vapors, but this usually isn’t the case.

However, if you can smell fuel vapors and have a P0453 code, it can make it a lot easier to troubleshoot what’s going on and find the source of the problem.

Causes of P0453 Code

There are many reasons for the FTP sensor to send an unnaturally high signal voltage. The common causes of the P0453 code include:

  1. Defective fuel tank pressure (FTP) sensor
  2. Defective carbon canister
  3. Defective carbon canister vent valve
  4. Issues with the FTP sensor circuit
  5. Damaged fuel tank
  6. An issue with the PCM, such as software in need of an update.

Read More: Symptoms and Causes of P0451

How to diagnose the P0453 code?

Follow the below-given steps to diagnose the P0453 code:

  • Use a scan tool (OBDI-II) to check for any stored trouble codes.
  • Normal voltages should be around 2.5 volts and 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 the 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 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.
  • Visually inspect the wiring and connectors of the EVAP system.

Common P0453 Diagnostic Mistakes 

The following are common mistakes when diagnosing the trouble code P0453:

  1. Checking the fuel tank pressure sensor resistance instead of voltage
  2. Assuming that there is a code stored when there isn’t one. If no codes are stored, it is an intermittent problem or a false fault
  3. Replacing parts without checking to see if they are good first. A new part may be faulty out of the box
  4. Forgetting to check the ground connection on the fuel tank pressure sensor circuit

P0453 Code Repair Cost

The repair cost of the P0453 code varies according to the repair type and labor cost. The following shows the repair cost of P0453 according to different the repair of different parts:

Ground connection repair$30 to $55
Fuel tank pressure sensor replacement$180 to $280
Low voltage signal wire repairing$10 to $90
Faulty PCM$530 to $870

FAQ Section

What repairs can fix the P0453 code?

  • Repair or replacement of wiring
  • Checking EVAP pressure sensor and/or FTP sensor
  • Repairing or replacing the connections
  • Replacing the affected component (Fuel Tank Pressure Sensor)
  • Repairing an open voltage signal wire 
  • Replacing a faulty PCM (Powertrain Control Module)

How serious is the P0453 code?

A P0453 code is not a major code and does not usually affect vehicle performance. However, a P0453 code can be a symptom of a more serious issue with the emissions system.

Can I drive with the P0453 Code?

You shouldn’t find it harder to drive a vehicle suffering from a code P0453 since the malfunctioning part doesn’t control any vital process. However, it’s still best to address this problem as soon as possible since a faulty FTP sensor can’t warn the PCM of any leak that may appear in the EVAP system.

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