OBD-II trouble code
P0450: Evaporative Emission System Pressure Sensor/Switch
SAE J2012 names P0450 as the evaporative emission pressure sensor or switch and does not set a voltage. Use the chart that stores P0450 on this vehicle. The 2007 Saturn Relay chart does not, and that chart does not print a displacement.
Quick facts
- System
- Powertrain
- Category
- Emissions / EVAP
- Severity
- Low severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $100 – $600
- DIY difficulty
- Intermediate DIY
Browse every code in P0400–P0499, or start from the full code library.
What does P0450 mean?
P0450 is Evaporative Emission System Pressure Sensor/Switch in the SAE J2012 list. A generic reader that prints P0450 is naming the sensor. The voltage, the enable conditions, and the circuit test are the chart that sets this code on this vehicle.
The 2007 Saturn Relay chart at gm.saturn.team path `/Saturn/Relay/2007/87/1/6261/143712` is titled DTC P0451, P0452, P0453, or P0454 and does not list P0450. P0452 is under 0.1 volt for more than 5 seconds. P0453 is over 4.9 volts for more than 5 seconds. Both run with the ignition on. P0451 is failure to re-zero during engine-off small-leak test P0442. Cap off, ignition on, engine off: 1.5 volts. Disconnected sensor: 0 volts. The circuit test uses a 3-amp fused jumper and a low reference under 5 ohms. Do not use those numbers because the tool printed P0450. The chart does not print “3.9L.” The 2008 Pontiac Torrent page at the matching path is titled the same four codes and does not contain P0450. Do not run that procedure because a generic reader printed P0450.
A chart that does set P0450 is the 2010 Pontiac Vibe AWD L4-2.4L service text, DTC P0450, P0452, or P0453. On that text the engine is running and intake-air temperature is between 4°C and 35°C (40°F and 95°F). P0450 sets if the signal is under 0.45 volt for 7 seconds or over 4.9 volts for 7 seconds. P0452 on that same text is the low-voltage code at the same 0.45-volt, 7-second condition, and P0453 is the high-voltage code at the same 4.9-volt, 7-second condition. With the filler cap removed and the ignition on, that text expects the parameter between 3.5 and 3.8 volts at sea level, and it says the reading varies slightly with atmospheric pressure. Those are that vehicle's numbers. They are not the Relay chart's 1.5 volts, and they are not a rest voltage for every P0450.
The Vibe text then tests the canister-harness circuits and replaces the sensor only after those circuits pass, or the PCM when a circuit test points there. Terminal numbers and resistance limits stay in that procedure. Another vehicle uses the chart that names the code it stored. The sensor is an evaporative-system input. It does not set injector pulse width.
Common causes
- A fuel-tank pressure circuit fault on a vehicle whose chart stores that fault as P0450
- On the 2010 Vibe AWD 2.4L text, a signal under 0.45 volt or over 4.9 volts for 7 seconds, engine running, intake air between 4°C and 35°C
- An open, a short, or a connector fault found by the circuit test in the chart that sets P0450 on this vehicle
- The fuel tank pressure sensor, after that chart's reference, signal, and low-reference tests have passed
- The control module, only on the branch where that same chart says the wiring tested normal
Symptoms
- Check engine light with P0450 stored
- On the 2010 Vibe AWD 2.4L text, a cap-off, key-on reading outside 3.5–3.8 volts at sea level
- EVAP monitor not completing
- No change in fuel control from this sensor
Diagnostic steps
- 1.Read the chart for the code this vehicle stored. SAE J2012 does not set a voltage for P0450. The 2007 Saturn Relay chart at gm.saturn.team path `/Saturn/Relay/2007/87/1/6261/143712` is titled DTC P0451, P0452, P0453, or P0454 and does not list P0450. Do not use its 0.1-volt or 4.9-volt set points, its 1.5-volt cap-off check, its 0-volt unplugged reading, its 3-amp fused jumper, or its under-5-ohm low reference because the tool printed P0450. The chart does not print “3.9L.”
- 2.On the 2010 Pontiac Vibe AWD 2.4L text, P0450 runs with the engine running and intake-air temperature between 4°C and 35°C (40°F–95°F). It sets under 0.45 volt for 7 seconds or over 4.9 volts for 7 seconds. P0452 and P0453 on that text use those same voltages as the separate low and high codes. Confirm which of those codes the tool stored before a part is ordered.
- 3.Cap removed, ignition on: that Vibe text expects 3.5–3.8 volts at sea level, and the reading varies with atmospheric pressure. A different vehicle uses its own rest value.
- 4.Follow the circuit test in the chart that names P0450 for this vehicle, including its connector, its terminal numbers, and its module-replacement branch. The Vibe text tests the harness at the EVAP canister assembly and does not use the Relay jumper. Do not copy either procedure onto a vehicle whose chart does not call for it.
- 5.Replace the sensor only when the chart for this vehicle says the circuits tested normal.
- 6.Fuel vapor can escape when the cap comes off a warm tank. Turn the cap slowly, outdoors or with ventilation, and keep ignition sources away.
Repair cost
$100 – $600
The low end of the printed bracket is the connector or the wire the chart for this vehicle fails before the sensor. The high end is the sensor, or the module if that chart's circuit tests point there, including the labor to reach the sensor where the diagram puts it. Read the bracket as a planning span, not a quoted price.
Estimate your repair
Run the numbers for your vehicle
Open the Repair Cost Estimator with evap system repair preselected. Adjust labor rate and vehicle category to fit your situation.
Related repairs
DIY vs shop
This is an intermediate DIY job. It usually involves diagnostic steps, specialty parts, and some careful work in tight spaces. If you have the tools and a service manual or trustworthy video for your specific vehicle, it is achievable in a weekend. Otherwise, a competent independent shop will be faster.