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Diagnostic code · Emissions / EVAP

Honda P145C Code: Fuel Tank Pressure Sensor

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What it meansOn US Hondas, the PCM has decided the fuel tank pressure sensor's signal can't be trusted.
Most likely fixReplace the fuel tank pressure sensor; check its wiring first if budget matters.
Safe to drive?Generally yes for a short while, roughly 30–50 miles of normal driving, but don't put it off.
Typical costSensor is cheap; labor varies widely by model
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’ll likely 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, often, the EVAP monitor that depends on that sensor simply won’t 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

The sensor itself fails first, most often. After that, 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 the next thing worth ruling out, and it’s the cheapest possible outcome if that’s all it turns out to be.

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 pricing a shop’s labor quote or planning your own afternoon — the part is simple, the access usually isn’t. If you’re working a Pilot rather than a sedan, expect that access question to look different again.

This code sometimes shows up in the company of other EVAP codes, including P0497 and P0455, and when it does, hard starting and rough idle can pile on top of the stall risk that P145C carries on its own. Worth mentioning all of it if you’re describing symptoms to a shop.

Driving on it briefly — call it 30 to 50 miles of ordinary use — is generally fine. Treat that as a window to get it looked at, not a green light to forget about it.

Common causes most common first

  • 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. Check whether the engine has stalled at low or moderate speeds, which is a symptom 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.
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Repair cost

The fuel tank pressure sensor itself is an inexpensive part. What makes the total unpredictable is labor: on some Honda and Acura models it's tucked in an awkward spot, and access time is what a shop is really charging for. If the actual fault turns out to be a wiring or connector issue rather than the sensor, that can end up being the cheapest outcome of the bunch.

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 often can't 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?
Yes, stalling at low or moderate speeds is a known symptom of this code. It doesn't happen on every vehicle, but it's common enough that it's worth mentioning if you're describing symptoms to a mechanic, especially at parking-lot speeds.
How urgent is a P145C code?
It's moderate, not an emergency. Short-term driving, roughly 30 to 50 miles of normal use, is generally acceptable. It shouldn't be ignored for long, though, partly because of the stall risk and partly because it can block an EVAP emissions check.
How much does it cost to fix P145C?
The fuel tank pressure sensor itself is inexpensive. The real variable is labor, since it's tucked in an awkward spot on many Honda and Acura models. If the actual cause is a wiring or connector fault instead, that can turn out to be the cheapest fix of all.