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A bad fuel tank pressure sensor shows up as P0451, P0452, P0453, or P0454, and on Acura platforms it is the first part to test. The 1811252 Fuel Tank Pressure Sensor covers the ILX (2003–2018), MDX (2005–2018), and CSX (2006–2011), and it supersedes Honda/Acura OEM numbers 36180-RCA-A01, 36180-RDV-J01, and 36180-RNA-A01.

The sensor reads vapor pressure from -7.5 kPa to +7.5 kPa and reports it as a 0–5V analog signal. The ECM uses that input to run OBD-II EVAP leak detection with sub-millibar resolution. A drifted sensor can set leak codes even when the tank holds vacuum, so test it before you replace canisters or purge valves.

1811252 Specifications at a Glance

2026 Material and Design Updates

The 2026 revision replaces the ceramic-diaphragm designs common in pre-2010 Acura service parts with a hermetically sealed MEMS element in a dual-cavity PPS thermoplastic housing. Four changes matter for repair outcomes:

Key upgrades in the 2026 revision

• PPS GF40 housing. The 40% glass-filled polyphenylene sulfide body resists E10 to E85 ethanol blends and prevents the micro-cracking documented in earlier nylon sensor bodies.
• FKM fluoroelastomer O-rings. FKM replaces NBR and closes the vapor permeation paths that trigger intermittent P0455 and P0442 codes after thermal cycling.
• Gold-plated terminal pins. The 0.64mm pins carry 15μ" gold flash over 50μ" nickel underplate, which removes the galvanic corrosion faults behind phantom P0453 high-voltage codes.
• Integrated RFI/EMI shielding. A conductive carbon-loaded PPS layer attenuates interference from 150 kHz to 1 GHz as 2026 vehicles add telematics and V2X modules.

ISO 26262 ASIL-B functional safety is preserved through redundant sensing elements, and the housing handles continuous exposure from -40°C to +125°C.

DTC Mapping and Diagnostic Flow

The Honda/Acura ECM validates FTP sensor rationality through a three-stage algorithm. Map each code to its root cause before you order parts:

Secondary codes and baseline checks

The sensor holds primary authority over P0451 through P0454 and resolves the full EVAP range from P0440 to P0455. P0441, P0440, and P0496 can appear as secondary codes when the ECM cannot establish a valid FTP baseline. Pull freeze-frame data and compare the stored FTP voltage against the calibration curve of 2.5V ±0.2V at atmospheric pressure.

Cross-Platform Fitment and Related Parts

The 1811252 spans three Acura EVAP architectures, and the same FTP design extends to Honda Civic (2006–2015), CR-V (2007–2016), and Accord (2008–2017). Each unit carries a laser-etched QR code linked to its calibration certificate and lot-level material test reports. Koeep keeps a 10-year NLA buffer stock, so the part stays available for legacy fleet maintenance after 2030.

If the same diagnostic session points at intake-side pressure, we carry the 37830-PHM-003 MAP sensor for Honda Prelude, Insight, and Acura NSX. For airflow and fuel metering faults, see the 37980-RNA-A01 MAF sensor for Civic, Accord, Odyssey, Pilot, RL, TSX, and ZDX.

EVAP codes caused by wiring damage or ECM faults call for electrical parts too. Browse the starters, alternators, ECUs, and wiring collection for those components. If you also service European cars, our VW Golf MK7 window control switch guide follows the same install-and-verify format.

Installation and Relearn Procedure

No ECM reflash is required on 2010–2018 Acura models. The sensor plugs straight into the SUMITOMO connector. Work through these steps after installation:

1. Disconnect the battery for 15+ minutes to reset the PCM and clear fuel trim adaptations.
2. Complete the CKP pattern relearn.
3. Run the Honda OBD-II drive cycle: cold start, idle 2 minutes; accelerate to 55 mph, hold 3 minutes; coast down to 20 mph without braking; accelerate to 60 mph, hold 5 minutes; decelerate to a stop, idle 1 minute.
4. Confirm Mode $06 results and TID $01 to $04 EVAP completion values with your scan tool.

The EVAP monitor runs within the first 30 minutes of that cycle. Every unit ships with a pre-validated calibration certificate confirming output linearity within ±1.5% of full scale across all pressure points.

Frequently Asked Questions