Parts for your 2018 Lexus Is-Map sensor

2018 Lexus IS MAP sensor: purpose, fitment, and service tips

Technical documentation confirms the 2018 Lexus IS uses a manifold absolute pressure (MAP) sensor across its engines. The Lexus/Toyota Repair Manual for IS (chassis codes including ASE30/GSE31/AVE30) includes a “Manifold Absolute Pressure Sensor” section and diagnostic trouble codes P0106–P0108, and the Toyota/Lexus Electronic Parts Catalogue lists MAP sensors for the IS range: 89421-0E040 for the 2.0L turbo 8AR-FTS (IS 300/200t), 89421-76020 for the 3.5L V6 2GR-FKS (IS 350/IS 300 AWD in some markets), and 89421-78010 for the 2.5L hybrid 2AR-FSE (IS 300h). These sources establish that a MAP sensor is fitted and relevant on the 2018 Lexus IS.

On a 2018 Lexus IS, the MAP sensor is a quiet achiever. It reads the pressure inside the intake manifold so the engine control module can nail the correct fuel delivery, spark timing, and—on turbo models—boost management. Whether it’s the punchy 2.0‑litre turbo, the silky V6, or the efficient hybrid, accurate manifold pressure data helps with smooth idle, crisp throttle, good economy, and clean emissions. It also lets the car adapt to altitude and temperature changes without fuss.

As part of routine servicing, the MAP sensor isn’t a scheduled replacement item, but it deserves a quick once‑over. A technician will typically check the electrical connector for a snug fit and clean pins, make sure the sensor’s O‑ring seal isn’t flattened or torn, and confirm there’s no oil mist or blow‑by gunk collecting around the port. On turbo models, it’s worth eyeballing both the manifold sensor and the separate boost/charge‑pressure sensor upstream, as build‑up there can skew readings too.

If drivability goes off—think rough idle, flat spots, higher fuel use, or a Check Engine Light—scan for fault codes like P0106, P0107, or P0108. When contamination is light, a careful clean with a sensor‑safe electronics cleaner can help, avoid poking the sensing element. If the sensor is faulty, replacement is straightforward: engine cool, connector off, two screws out, swap the O‑ring if needed, and refit. Sticking with a genuine or high‑quality aftermarket unit keeps the calibration spot‑on. After replacement, clearing codes and taking a gentle test drive lets the ECU settle its trims. For drivers in Aus and NZ clocking lots of city kays, pairing MAP checks with PCV and air‑filter inspections helps prevent grime from returning under the bonnet.

• Typical symptoms of a dodgy MAP sensor: hard starting, surging, black smoke on launch, poor economy, and stored DTCs.
• Good habits: keep the intake airtight, service the air filter on time, and ensure connectors and earths stay clean and dry.

Popular questions

Does the 2018 Lexus IS have both a MAF and a MAP sensor?
Yes. The 2018 IS range uses a mass air flow (MAF) sensor to measure incoming air and a MAP sensor to read pressure in the manifold. The turbo 2.0L also uses a charge‑pressure sensor before the throttle to help manage boost. The ECU blends these signals for accurate load calculation and smooth response.

Where is the MAP sensor located on a 2018 IS?
It’s mounted on the intake manifold, typically near the throttle body. On the 2.0T there’s also a separate boost sensor on the charge pipe. The MAP sensor sits directly in manifold vacuum/boost and seals with an O‑ring, so there’s no separate vacuum hose to chase.

Should the MAP sensor be cleaned or replaced during service?
It isn’t a routine replacement item. If the car drives well and shows no codes, it’s usually left alone. If issues arise or light contamination is spotted, a gentle clean with sensor‑safe electronics cleaner can restore readings. Replace the sensor if it’s failed, damaged, or repeatedly triggers MAP‑related fault codes.