OBD-II Code
P0450
Severity
Not yet reviewed
Nobody on our side has assessed this code yet, so we are not going to guess at how serious it is.
Can you drive it
We cannot say
Treat it as unknown until a shop reads it with live data. If the check-engine light is FLASHING, stop driving as soon as it is safe to — that means an active misfire, whatever the code.
Indicative cost (USD)
$70–$350
From this code's diagnostic notes. Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
P0450 is the generic EVAP pressure sensor (also called fuel tank pressure sensor or FTPS) malfunction code - the ECM detected a sensor reading that's electrically valid but doesn't behave plausibly during normal operation or leak-test cycles.
How a shop works this
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.
Note every code that is set, not just this one.
Codes that appear together usually narrow the cause faster than any one of them read alone.
Read the freeze frame — the conditions the fault was recorded under.
Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.
Confirm the fault is current rather than history.
Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.
Then follow the diagnostic notes further down this page, in the order they are written.
They are written in the order a shop works this code, cheapest checks first. Where they name a component, inspect its wiring and connector before replacing it.
If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.
Common symptoms
- Check engine light
Read the full diagnostic procedureP0450 is the generic EVAP pressure sensor (also called fuel tank pressure sensor or FTPS) malfunction code - the ECM detected a sensor reading that's…
P0450 is the generic EVAP pressure sensor (also called fuel tank pressure sensor or FTPS) malfunction code - the ECM detected a sensor reading that's electrically valid but doesn't behave plausibly during normal operation or leak-test cycles. The FTPS is a piezo-resistive transducer that monitors EVAP system pressure or vacuum, and on most modern vehicles outputs a 0.5 to 4.5V signal corresponding to roughly atmospheric (about 2.5V at sea level) down to negative 7 to 10 inches of water column during purge events.
Cheapest-first ladder
- scan-tool the live FTPS data with the engine off and the gas cap removed - the sensor should read very close to atmospheric (typically 2.4 to 2.6V or the OEM 'zero' equivalent).
- With the gas cap installed and the engine running and warm, command an EVAP purge via bidirectional control and watch the FTPS go slightly negative as the purge valve draws vacuum on the tank.
- If the sensor flatlines, jumps erratically, or fails to respond to commanded purge, it has failed.
- Backprobe the connector and verify 5V reference (4.9 to 5.1V), clean ground (under 0.1V drop), and a smooth signal voltage that tracks system pressure changes.
- The expensive misdiagnosis is replacing the entire fuel pump module assembly when the FTPS is the only failed component - on many platforms (especially GM trucks) the sensor is a separately-serviceable part that mounts on top of the fuel pump module or on a dedicated saddle-tank port, so verify part availability before quoting a $400 to $800 pump module.
Vehicle-specific patterns1999-2013 GM full-size pickups with saddle-tank fuel systems (Silverado, Sierra, Suburban, Tahoe 1500-3500) are the classic P0450 platform - the FTPS…
- 1999-2013GM full-size pickups with saddle-tank fuel systems (Silverado, Sierra, Suburban, Tahoe 1500-3500) are the classic P0450 platform - the FTPS mounts on the cross-over line between the two saddle tanks and gets fuel-soaked from a leaking quick-connect, killing the sensor. The aftermarket sells the standalone FTPS for $40 to $90 even though the dealer wants to sell the full crossover assembly.
- 2005-2014Subaru EJ-series (Outback, Forester, Legacy) FTPS mounts on top of the fuel pump module under the rear seat and fails from heat aging plus fuel vapor exposure - typically presents around 120k to 150k miles.
- 2007-2014Toyota Tundra/Sequoia 5.7L FTPS fails from connector corrosion when the pump module gasket weeps fuel.
- 2009-2014Ford F-150 FTPS gets damaged when the EVAP canister is replaced and the sensor connector pin gets bent during reinstallation.
Estimated repair$70 to $350.
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