P0454: Evaporative emission control system pressure sensor signal is intermittent
EVAP pressure sensor circuit intermittent
Severity: Severity not verified — if the car runs badly, have it inspected
Kelley Blue Book says the code is not usually very serious at first and rarely causes noticeable symptoms, but also says it will fail an emissions test and advises against long-term driving with it active. The two statements differ, so no class is set.
P0454 in short
P0454 means the engine computer saw an intermittent signal from the evaporative emission (EVAP) system pressure sensor. Kelley Blue Book lists the sensor, its wiring, the purge solenoid, canister, vapor hoses and fuel cap as causes. It rarely changes how the car drives, but it will fail an emissions test.
The EVAP system traps fuel vapour and feeds it to the engine. A pressure sensor lets the computer watch the system pressure.
If that sensor signal drops in and out, the computer stores P0454. Kelley Blue Book notes the code points to a problem somewhere in the EVAP system without saying where, so check the simple items first.
Most likely causes
These are general causes for this code across vehicles. None is specific to one make or model.
Cause 1: Loose, open or damaged fuel cap
Common general cause- Why it ranks here
- Kelley Blue Book says the most common cause is an open fuel cap or a slight vacuum leak.
- What would change this
- Rises if the cap was left loose or its seal is cracked. Falls if the cap seals well.
Cause 2: Faulty EVAP pressure sensor
Common general cause- Why it ranks here
- Kelley Blue Book lists a bad EVAP pressure sensor first, and the code is about that sensor's signal.
- What would change this
- Rises if the sensor voltage jumps with no pressure change. Falls if it reads steadily.
Cause 3: Wiring or connector fault at the sensor
Common general cause- Why it ranks here
- Kelley Blue Book lists electrical wiring and connector problems, which suit an intermittent signal.
- What would change this
- Rises if the signal changes when the harness is wiggled. Falls if the wiring tests good.
Cause 4: Faulty purge control solenoid
Possible — needs testing- Why it ranks here
- Kelley Blue Book lists the purge solenoid, but only as one of several EVAP parts to check.
- What would change this
- Rises if the valve sticks or leaks. Falls if it operates normally.
Cause 5: Damaged charcoal canister or cracked vapour hoses
Possible — needs testing- Why it ranks here
- Kelley Blue Book lists a clogged or broken canister and cracked hoses or vacuum tubes.
- What would change this
- Rises if a smoke test shows a leak or the canister is damaged. Falls if the system holds pressure.
What to test first
Start at step 1. Each result tells you what it means and where to go next.
Step 1: Read all stored codes and check the fuel cap is fitted and tight.
IfOther EVAP codes are stored
It meansLook for a shared cause such as a leak or the purge valve.
IfOnly P0454 is stored
It meansInspect the system and sensor wiring.
Step 2: Visually inspect the EVAP hoses, lines, harness and sensor connector, then test the sensor circuit with a voltmeter and ohmmeter.
Warning:Fuel vapour is flammable, so work with the engine off and away from sparks, and keep meter leads from shorting adjacent pins.
IfDamaged wiring or a loose connector is found
It meansA circuit fault is likely.
IfWiring is sound but the signal is erratic
It meansThe sensor is suspect.
Step 3: Have the EVAP system smoke tested to find leaks in hoses, canister or cap.
Warning:Use only low-pressure smoke equipment made for EVAP systems; high pressure can damage the sensor and canister.
IfSmoke escapes
It meansRepair the leak source.
Points to: Damaged charcoal canister or cracked vapour hoses
IfNo leak
It meansCheck the purge valve and sensor.
Symptoms
- Check engine light on
- Slight drop in fuel economy
- Faint fuel smell
- Fails an emissions test
How to fix
Step 1: Make sure the fuel cap is fitted and clicked tight, then see whether the light returns after several drives.
Parts and cost context
- Fuel (gas) cap:A cap is inexpensive to try if the seal looks worn. Confirm the fault first. Labour varies; get a quote.
Labor varies by vehicle and shop; get a quote before you approve a repair.
Compare used part prices on PartPriceGuideOn your vehicle
We don't have reviewed vehicle-specific evidence for P0454 yet. The causes and tests above apply across vehicles.
Related codes
P0454 questions
Can I drive with P0454?
Kelley Blue Book says it is not usually serious at first and rarely causes symptoms, but advises against driving long with it active and notes it will fail an emissions test.
Sources and review
- Last reviewed
- Written by
- Saurabh K.
- Editorial review
- Pending
- Technician review
- Technician review pending
This page explains what a code usually means; it is not a substitute for a professional inspection. How we source and review · Report an error