What causes fault code P0450?

• Most likely: Faulty EVAP Pressure Sensor (FTP sensor) • Likely: Damaged wiring harness or corroded connectors to the sensor • Possible: Clogged charcoal canister or blocked vent lines • Rare: Internal ECU failure • Rare: Poor sensor ground connection

Powertrain (Engine & Gearbox)Standard EOBD

P0450 - Evaporative Emission (EVAP) System Pressure Sensor / Switch

Q: What are the symptoms of fault code P0450?

• Check Engine Light (MIL) illuminated • Fuel vapor odor around the vehicle • Difficulty refueling (gas pump nozzle clicks off repeatedly) • Slight decrease in fuel economy • Failed emissions test

Q: How do you fix fault code P0450?

STEP 1: Inspect the connector at the fuel tank pressure sensor for corrosion or loose pins. Clean as necessary. STEP 2: Use a multimeter to verify the 5V reference signal and ground from the ECU. Verify continuity in the signal wire back to the ECU. STEP 3: Monitor FTP sensor data using a scan tool. With the fuel cap removed, the reading should stabilize near atmospheric pressure (commonly around 1.5V to 4.5V depending on manufacturer calibration). STEP 4: Inspect the charcoal canister and vent lines for kinks, blockages, or liquid fuel saturation. STEP 5: If wiring and supply voltages are correct but the signal is erratic or frozen, replace the FTP sensor.

Last updated:1 February 2026

Related:FTP-sensor, Kolfilter (Charcoal Canister), Engine Control Unit (ECU), Tanklock, Avluftningsventil (Purge Valve)

System

Powertrain (Engine & Gearbox)

Related Fault Codes

P0400

Exhaust Gas Recirculation Flow Malfunction

P0401

Exhaust Gas Recirculation (EGR) Flow Insufficient Detected

P0402

Exhaust Gas Recirculation Flow Excessive Detected

P0403

Exhaust Gas Recirculation (EGR) Control Circuit

Technical Description

P0450 is a generic OBD-II diagnostic trouble code (DTC) indicating a malfunction in the Evaporative Emission (EVAP) system pressure sensor circuit. The Fuel Tank Pressure (FTP) sensor monitors pressure/vacuum in the fuel tank to detect leaks. The ECU monitors the sensor for voltage signals that are outside of specified ranges or exhibit irrational behavior compared to atmospheric pressure sensors (BARO) during key-on intervals. This code specifically points to a circuit-level malfunction rather than a leak detection failure. If the ECU cannot verify the tank pressure, it may disable the EVAP monitor and purge logic, potentially affecting engine adaptation values.

Possible Causes

Faulty EVAP Pressure Sensor (FTP sensor)

Damaged wiring harness or corroded connectors to the sensor

Clogged charcoal canister or blocked vent lines

Internal ECU failure

Poor sensor ground connection

Symptoms

Check Engine Light (MIL) illuminated

Fuel vapor odor around the vehicle

Difficulty refueling (gas pump nozzle clicks off repeatedly)

Slight decrease in fuel economy

Failed emissions test

Do you also have
other fault codes?

See how P0450 connects with your other fault codes. Our advanced analysis tool identifies causal relationships and root causes directly.

Analyze multiple codes

P0450 - Evaporative Emission (EVAP) System Pressure Sensor / Switch

Related Fault Codes

Technical Description

Possible Causes

Symptoms

Recommended Solution

Workflow

Mechanic's Tip

Do you also have
other fault codes?

P0450 - Evaporative Emission (EVAP) System Pressure Sensor / Switch

Related Fault Codes

Technical Description

Possible Causes

Symptoms

Recommended Solution

Workflow

Mechanic's Tip

Do you also have other fault codes?

Do you also have
other fault codes?