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Diagnostic code · Emissions / EVAP

Honda P145C Code: Fuel Tank Pressure Sensor

Updated October 8, 2026Sources

On this page 4 sections
Meaning
On US Hondas, the PCM has decided the fuel tank pressure sensor's signal can't be trusted.
Checks to start with
Live fuel tank pressure data, then the sensor's wiring and connector before the sensor itself.
Safe to drive?
If the light is steady, Honda says to avoid high speeds and have the vehicle inspected immediately. If it starts flashing, stop safely.

If you looked this code up and found two completely different definitions, you're not looking at a mistake. P145C means one thing on a US-market Honda (a fuel tank pressure sensor problem) and something else in Japanese-market documentation (an EVAP purge flow problem). For a US owner, the fuel tank pressure sensor is the one that applies.

What P145C means

Search this code and you may find two answers that don’t agree with each other. One source says fuel tank pressure sensor. Another says EVAP purge flow. Neither is a typo. Honda assigned P145C two different jobs depending on the market: US-market vehicles use it for a fuel tank pressure sensor fault, while Japanese-market documentation (and some other Asian-market references) uses the same four characters for an EVAP purge flow malfunction. If your Honda was sold in the US, the fuel tank pressure sensor is the one that matters here.

What the sensor actually does

The fuel tank pressure sensor watches pressure inside the tank as part of how the EVAP system manages fuel vapor. The PCM leans on that reading to run its EVAP checks and to know the system is sealed properly. When the signal stops making sense — a value that’s implausible, one that doesn’t move when it should, or one that jumps around too fast to be real — the PCM can’t trust it anymore. Rather than guess, it stores P145C, and the EVAP monitor that depends on that sensor may not run.

That last part matters more than it sounds. An incomplete EVAP monitor can fail an emissions test on its own, separate from whatever the stored code itself would cause. If you’re heading toward an inspection, that’s the piece to flag early.

Tracking down the actual fault

Start with the sensor’s signal, then look at the wiring: EVAP circuits run through areas exposed to road grime and corrosion over the years, and a damaged or corroded wire can feed the PCM the same kind of nonsense signal a bad sensor would. A loose or corroded connector at the sensor itself is also worth ruling out.

Where the sensor actually sits differs a lot across Honda and Acura models, and it’s rarely somewhere convenient. That’s worth knowing going in, whether you’re getting a shop’s labor quote or planning your own afternoon — the part is simple, the access may not be. If you’re working on a Pilot rather than a sedan, expect that access question to look different again.

This code sometimes shows up alongside other EVAP codes, including P0497 and P0455, and when it does, hard starting and rough idle can add to the stall risk that P145C carries on its own. If you’re describing symptoms to a shop, mention all of it.

If the check engine light is steady, Honda says to avoid high speeds and have the vehicle inspected immediately. If the light starts flashing, stop safely.

Possible causes

  • Faulty fuel tank pressure sensor
  • Damaged or corroded EVAP wiring
  • Loose or disconnected wiring at the sensor
  • Corroded electrical connector at the sensor

Do these checks first

  1. Confirm which definition applies to your Honda, since US-market cars should treat this as a fuel tank pressure sensor code, not a purge flow code.
  2. Have a scan tool watch live fuel tank pressure data for a reading that's frozen, erratic, or clearly out of range.
  3. Note whether the engine has stalled at low or moderate speeds; that's worth mentioning to whoever diagnoses it.
  4. Ask if EVAP monitors are showing as incomplete, since that alone can block an emissions test.
  5. Inspect the wiring and connector at the sensor for corrosion or a loose pin before assuming the sensor itself is bad.

FAQ

What does P145C mean on a Honda?
On a US-market Honda, it means the PCM doesn't trust the signal from the fuel tank pressure sensor. That sensor helps run the EVAP system, and once its reading looks implausible or erratic, the PCM stores this code and may not be able to complete its EVAP checks either.
Why do I see two different definitions for P145C online?
Honda uses this code for two different faults depending on the market. US-market vehicles use it for the fuel tank pressure sensor. Japanese-market documentation uses the same code for an EVAP purge flow issue. Both are correct for their own market; a US owner should go with the sensor definition.
Can P145C cause my Honda to stall?
It can. Stalling at low or moderate speeds is a symptom reported with this code. It doesn't happen on every vehicle, but if you've had stalls, especially at parking-lot speeds, mention them when you describe symptoms to a mechanic.
How urgent is a P145C code?
If the check engine light is steady, Honda says to avoid high speeds and have the vehicle inspected immediately. If the light starts flashing, stop safely. P145C also carries a stall risk and can block an EVAP emissions check.

Sources

Owner's manual references are to the model and year named above. Wording and procedures can differ on your Honda, so check your own owner's manual.

How we source and correct →