P0454 Evaporator Emission System Pressure Sensor Intermittent

P0454 Evaporator Emission System Pressure Sensor Intermittent

OBD-II DTC Datasheet

Intermittent signal of the pressure sensor of the control system for the removal of fuel vapor

What does this mean?

This Diagnostic Trouble Code (DTC) is a generic transmission code, which means it applies to OBD-II equipped vehicles (Dodge, Ram, Ford, GMC, Chevrolet, VW, Audi, Toyota, etc.). Although general, specific repair steps may differ depending on the brand / model.

When your OBD-II equipped vehicle displays code P0454, it means the powertrain control module (PCM) has detected an intermittent signal from the EVAP pressure sensor circuit.

To trap fuel vapors before they escape into the atmosphere, the EVAP system uses a vented reservoir (commonly called a canister) to store excess fuel vapors until the engine is operating under the right conditions to burn them efficiently.

The vapors from the fuel tank are discharged through the safety valve (at the top of the fuel tank). The pressure generated during storage of the fuel acts as a propellant and forces the vapors to escape through a network of metal pipes and rubber hoses; eventually get to the charcoal storage canister. The canister not only absorbs fuel vapors, but also holds them for release at the right time.

A typical EVAP system consists of a carbon tank, an EVAP pressure sensor, a purge valve / solenoid, an exhaust control valve / solenoid, and an intricate system of metal pipes and rubber hoses that runs from the fuel tank to the engine compartment.

The purge control valve / solenoid, which is the hub of the EVAP system, is electronically controlled by the PCM. The purge control valve / solenoid is used to regulate the vacuum at the inlet to the EVAP canister so that fuel vapors are drawn into the engine when conditions are ideal to burn them as fuel instead of polluting the atmosphere.

EVAP pressure is monitored by the PCM using an EVAP pressure sensor. The EVAP pressure sensor can be difficult to access as it is usually located at the top of the fuel tank and is embedded in the fuel pump / fuel delivery unit housing. If the PCM detects that the EVAP pressure signal is intermittent, a code P0454 will be stored and the Malfunction Indicator Lamp (MIL) may illuminate.

Associated emission DTCs include P0450, P0451, P0452, P0453, P0455, P0456, P0457, P0458, and P0459.

Code severity and symptoms

Symptoms of this code may include:

• In most cases, symptoms with a P0454 code will not appear.
• Slight reduction in fuel efficiency
• MIL Illumination (Malfunction Indicator Lamp)

reasons

Possible reasons for setting this code:

• Faulty EVAP pressure sensor
• Fuel tank relief valve clogged.
• Open or short circuit in the wiring or connectors of the EVAP pressure sensor
• Cracked or Broken Charcoal Canister

Diagnostic and repair procedures

If I come across a P0454 code diagnosis, I know I will need a diagnostic scanner, a digital volt / ohmmeter, a reliable source of vehicle information like All Data DIY, and maybe even a smoke machine.

A visual inspection of the hoses, lines, electrical harnesses, and connectors of the EVAP system is a good place to start diagnosing. Pay special attention to parts near sharp edges or hot exhaust system components. Don't forget to remove the fuel tank cap, inspect the seal and tighten it properly.

Then I like to connect the scanner to the car diagnostic port and retrieve all stored codes and freeze frame data. It is a good idea to write this information down because it can be very useful, especially if it turns out to be intermittent code. After that, I like to clear the codes and test drive the car until it enters OBD-II ready mode or the code is cleared. EVAP codes typically require multiple drive cycles (with each failure) before resetting.

Observe the signal from the EVAP pressure sensor using the scanner's diagnostic stream. I know I have corrected the condition (by tightening or replacing the fuel cap) if the system pressure is within the manufacturer's recommended specifications,

I would check the EVAP pressure sensor before doing the smoke test because it is an intermittent pressure sensor circuit code. The location of the EVAP pressure sensor can complicate testing as it is usually located at the top of the fuel tank. Once accessing the sensor, follow the manufacturer's testing guidelines and replace the sensor if it is out of specification.

Disconnect all associated controllers and check individual circuits with DVOM if EVAP pressure sensor meets manufacturer specifications. Repair or replace open or shorted circuits as necessary and retest the system.

Additional diagnostic notes:

• Low or high EVAP pressure may cause the P0454 to persist.
• This code can be caused by electrical or mechanical problems.

Related DTC discussions

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