Michigan Motorsports 4-Bar MAP Sensor | Like GM #25203477 & #12643955 | 0-44psi Boost MAP for LS3-Style Ports & GM Duramax Engines

Upgrade your engine management with this Genuine GM 4‑Bar MAP Sensor (PN 25203477, superseding 12643955)—designed to monitor up to 44 psi of boost accurately. Engineered by GM, this sensor drops directly into LS3-style intake manifold ports and 2011–2016 LML/LLY 6.6 L Duramax trucks, delivering accurate pressure data for forced-induction, turbo, and supercharged setups. A popular choice among Holley EFI users, this sensor ensures clean, reliable boost measurements for precise tuning. Note: requires pigtail #13580231 or trimmed LS9/LS3/LSA connectors.

• OEM‑Supplied by GM – Genuine factory part, supersedes 12643955; engineered for durability and accurate boost readings.
• High‑Boost Rated (0–44 psi) – 4-Bar capacity gives full scale reading through high-boost zones—perfect for turbocharged or supercharged LS & Duramax builds.
• Direct Fit for LS3 Intake Ports – Drops into LS3-style MAP bosses without gaskets or adapters—ideal for LS3, L99, LSA, and other LS swaps.
• Used on GM 6.6 L Duramax (2011–2016) – OE on LML and LLY models, trusted for reliability under heavy towing and boost loads.
• Trusted Holley EFI Upgrade – Heavy-duty, precision sensor backed by tuners; widely recommended in Holley and other EFI forums.