P0452
Evaporative Emission Control System Pressure Sensor Low InputP0452 is a generic OBD-II powertrain diagnostic trouble code: Evaporative Emission Control System Pressure Sensor Low Input. It is logged by the engine control unit when the powertrain monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.
What P0452 means
P0452 is set when the PCM reads an abnormally low voltage signal from the EVAP system pressure sensor (also called the fuel tank pressure sensor, FTP sensor). The sensor is typically a three-wire variable-resistance or variable-voltage device mounted on or near the charcoal canister or fuel tank, providing the PCM with a continuous pressure/vacuum reading inside the EVAP system. The PCM expects the sensor output to stay within a defined voltage window (usually 0.1–4.9 V); a reading that falls below roughly 0.1–0.2 V for a calibrated period is interpreted as a sensor or circuit fault and P0452 is stored.
The most common causes are a short to ground somewhere in the signal wire between the sensor and the PCM, a failing sensor whose output has drifted to the lower rail, or a corroded/damaged connector that effectively grounds the signal line. Because the sensor is mounted under the vehicle near the fuel tank, it is exposed to road salt, water spray, and physical damage. On some platforms the sensor is integrated into the charcoal canister assembly and must be replaced as a unit.
P0452 by itself does not immediately affect engine operation, but with a failed pressure sensor the PCM cannot run its EVAP leak detection monitor, so the EVAP readiness monitor will remain incomplete. This will cause a failure at an OBD-II emissions inspection.
Common causes
Most-frequently reported root causes when P0452 is logged.
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1
Short to ground in the FTP sensor signal wire
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2
Defective fuel tank pressure (FTP) sensor with output stuck at or near 0 V
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3
Corroded, water-damaged, or backed-out terminals at the FTP sensor connector
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4
Damaged wiring harness between FTP sensor and PCM (chafing on fuel tank straps or body)
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5
Open or high-resistance reference voltage circuit preventing sensor bias voltage
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6
Failed PCM sensor input (rare, after confirming external circuit integrity)
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7
Sensor contaminated by liquid fuel (sensor port flooded due to overfilling)
Symptoms drivers notice
How to diagnose P0452
A typical diagnostic flow when this code is present.
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1
Retrieve all codes and check for companion EVAP codes; record freeze-frame fuel-tank pressure sensor voltage
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2
With the key on, engine off, use a scan tool to read the FTP sensor PID — a reading below 0.2 V (or the manufacturer's minimum) confirms the low-input condition
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3
Inspect the FTP sensor wiring from the sensor connector to the PCM for chafing, cuts, or corrosion, particularly along the fuel tank and undercarriage runs
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4
Unplug the sensor and measure voltage on the reference (5 V) and ground wires; also check for continuity between the signal wire and chassis ground (there should be none)
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5
With the sensor unplugged, measure signal wire voltage at the PCM connector — should read near 5 V (pulled up); if it reads 0 V the wire is shorted to ground between sensor and PCM
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6
If wiring checks out, substitute a known-good FTP sensor or measure the suspect sensor's output across a range of pressures using a hand vacuum pump
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7
Clear code, run an EVAP drive cycle, and verify the readiness monitor completes after repair
Related powertrain codes
- P0400 — Exhaust Gas Recirculation Flow Malfunction
- P0401 — Exhaust Gas Recirculation Flow Insufficient Detected
- P0402 — Exhaust Gas Recirculation Flow Excessive Detected
- P0403 — Exhaust Gas Recirculation Circuit Malfunction
- P0404 — Exhaust Gas Recirculation Circuit Range/Performance
- P0405 — Exhaust Gas Recirculation Sensor A Circuit Low
Frequently asked questions
Can overfilling the fuel tank cause P0452?
Yes. Repeatedly overfilling the tank can force liquid fuel into the charcoal canister and flood the FTP sensor port, causing the sensor to output a low or erratic signal. If liquid fuel contamination is found in the canister, the canister and sensor should both be replaced.
What is the difference between P0452 and P0453?
P0452 is a low-voltage input (signal at or near 0 V), usually caused by a short to ground or a failing sensor whose output has collapsed. P0453 is a high-voltage input (signal near 5 V or above), usually caused by an open circuit or a short to voltage on the signal wire.
Will P0452 prevent passing an emissions test?
Yes. With the FTP sensor faulted the EVAP readiness monitor cannot complete, which results in an incomplete monitor status. Most states and countries will fail a vehicle at an OBD-II inspection if the EVAP monitor is incomplete.
Where is the fuel tank pressure sensor located?
Location varies by manufacturer. On most vehicles it is mounted on top of the fuel tank, on the charcoal canister assembly, or on the vapor line between the tank and canister. A vehicle-specific repair manual is the reliable way to locate it before starting the diagnosis.
Disabling P0452 in software
RaceTune can permanently disable P0452 — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.
Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.
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