P0452: Evaporative Emission System Pressure Sensor/Switch Low
Quick Answer
Safe to drive (short-term)
P0452 means the voltage coming from the fuel tank pressure sensor is lower than the engine computer expects to ever see. It points to a sensor that has died, a signal wire shorted to ground or a lost 5 volt supply. It is an electrical fault first, and a vapour leak does not cause it.
- Severity
- Low · EVAP System
- Estimated repair cost
- From €45 to €430+, varies by vehicle
€45 or €430, depending on your car.
- Repair sensor wiring or clean connector€45–€160
- Drop the fuel tank to reach the sensor or its harness€150–€430
A scan shows whether P0452 is really stored on your car, which codes sit next to it and how urgent each one is.
A scan needs a Bluetooth OBD2 adapter (Bluetooth LE on iPhone), about €25-60; the built-in demo runs without one. See which adapter to buy
What does P0452 mean?
P0452 is a evap system-related diagnostic trouble code classified as low severity.
Where it is on the car
- Fuel filler cap
- Fuel tank pressure sensor
- Charcoal canister
- Vent valve (to fresh air)
- Purge valve
- Intake manifold and engine
What are the symptoms of P0452?
- Check engine light on
- Nothing noticeable in how the car drives
- Tank pressure value in live data stuck near the bottom of its range, if your reader shows it
- Fails an inspection because of the warning lamp
- EVAP readiness stays not ready after codes are cleared
What causes P0452?
Fuel tank pressure sensor failed or reading near zero volts
: high
Signal wire shorted to ground or chafed through
: high
Open or shorted 5 volt reference supply at the sensor connector
: medium
Damaged harness between the sensor and the body connector, often on top of the tank
: medium
Water or corrosion in the connector
: low
Is it safe to drive with P0452?
Generally yes, for short-term driving. You can keep driving. A low signal from the tank pressure sensor does not affect how the engine runs. The computer cannot judge the vapour system, so the light stays on and the car can fail a check that looks at it.
How do you diagnose P0452?
- Read the freeze frame and check whether P0453 or other EVAP codes are stored as well. A sensor circuit code with no leak code points away from the fuel cap
- If live data shows tank pressure, note the value with the fuel cap off. It should sit near zero pressure, and one that stays at the bottom of its range is suspect
- Check the sensor connector and harness for water, green corrosion and wiring that rubs on the tank or a bracket
- With the connector unplugged and ignition on, measure the 5 volt reference at the plug. No reference means a wiring or computer-side fault, normal reference with a dead signal means the sensor or the signal wire
- Look for a signal wire shorted to ground by checking resistance to a body ground with the battery disconnected
- Clear the code and complete several drive cycles. If it returns and the wiring tests good, the sensor is the likely part, and on some cars the tank has to come down to reach it
How much does P0452 cost to fix?
| Repair | Parts Cost | Labor Cost | Total Estimate | DIY Difficulty |
|---|---|---|---|---|
| Repair sensor wiring or clean connector | €5–€40 | €40–€120 | €45–€160 | Moderate |
| Replace fuel tank pressure sensor | €40–€160 | €50–€200 | €90–€360 | Moderate |
| Extended diagnosis of the sensor circuit with wiring diagram | €0–€0 | €60–€130 | €60–€130 | Professional |
| Drop the fuel tank to reach the sensor or its harness | €0–€30 | €150–€400 | €150–€430 | Professional |
Prices estimated as of October 2026. Costs vary by region, vehicle, and shop.
P0452 on specific vehicles
P0452 on Saab
Saab 9-5 (V6)
Related diagnostic codes
Common questions about P0452
- What does a low input on the fuel tank pressure sensor mean?
- The sensor signal sits below its normal range. The usual reasons are a failed sensor, a signal wire shorted to ground or a lost 5 volt supply. The code describes the electrical signal, not the pressure in the tank.
- Can a bad fuel cap cause P0452?
- No. P0452 is set by a signal voltage near zero, which a leaking or loose cap does not produce. A cap problem sets leak codes such as P0455 or P0456 instead.
- Is P0452 expensive to fix?
- Often not. A wiring repair or connector clean is the cheap end, and a new sensor is a modest part. The bill rises when the sensor sits inside the tank or behind the canister and needs extra labour to reach.
- Should I replace the sensor straight away?
- Test first. A chewed or chafed wire and a missing 5 volt supply set the same code, and a new sensor will not fix either.
- Will this code stop the engine from running well?
- No. The sensor feeds the vapour leak test only. The light stays on until the fault is fixed and the computer has re-run its test.
Read our detailed guides
Sources
- saabwisonline.com saabwisonline.com/9-5-9650/2011/2-engine/engine-management-and-fuel-system-v6/fa