P0303 on Lexus vehicles Cylinder 3 is misfiring

A model year is listed because the code is named in its own record — a bulletin filed against it, or an owner’s complaint about it — not because every one of these vehicles sets it. Counts are documents in NHTSA’s files, not failure rates.

Bulletins and campaigns Lexus filed with NHTSA whose summary names P0303. Quote the document number at the service desk — it is a diagnosis the maker has already written down.

• L-SB-0045-12 Rev Service bulletin
  2017-12-13 · Equipment — Other — Owners/Service/Other Manual
• TSB: REVISION NOTICE December 13, 2017 Rev1: ? Applicability has been updated to include 2013 ? 2017 model year RX 450h vehicles. ? The Introduction and Repair Procedure sections have been updated. Any previous printed versions of this bulletin should be discarded. Some 2010 ? 2017 model year RX 450h vehicles may exhibit one or more of the following conditions: ? MIL ?ON? with DTC P0300/00, P0301/
• L-SB-0045-12 Rev Service bulletin
  2017-12-13 · Engine
• TSB: REVISION NOTICE December 13, 2017 Rev1: Applicability has been updated to include 2013 ? 2017 model year RX 450h vehicles. The Introduction and Repair Procedure sections have been updated. Any previous printed versions of this bulletin should be discarded. Some 2010 ? 2017 model year RX 450h vehicles may exhibit one or more of the following conditions: MIL ?ON? with DTC P0300/00, P0301/00, P0
• L-SB-0044-19 Service bulletin
  2019-11-18 · Equipment
• TSB: Some 2016 ? 2019 model year RX450h and 2018 ? 2019 model year RX450hL vehicles may exhibit a MIL ON condition with one or more of the following Diagnostic Trouble Codes (DTCs): ? P0301 ? Cylinder 1 Misfire Detected ? P0302 ? Cylinder 2 Misfire Detected ? P0303 ? Cylinder 3 Misfire Detected ? P0304 ? Cylinder 4 Misfire Detected ? P0305 ? Cylinder 5 Misfire Detected ? P0306 ? Cylinder 6 Misfire
• L-SB-0019-16 Service bulletin
  2016-06-08 · Engine
• TSB: SOME 2011 – 2016 MODEL YEAR CT 200H (2ZR-FXE EQUIPPED) VEHICLES MAY EXHIBIT A “RUNS ROUGH” AND/OR MIL “ON” CONDITION WITH DTC(S) P0300, P0301, P0302, P0303, AND P0304 (MISFIRE) DURING LIGHT ACCELERATION WHILE THE EXHAUST GAS RECIRCULATION (EGR) SYSTEM IS ACTIVE. THIS CONDITION CAN BE CAUSED BY CLOGGED EGR PORTS IN THE INTAKE MANIFOLD ASSEMBLY. IF THE EGR PORTS ARE CLOGGED, THEN REPLACE THE I
• L-SB-0019-16 Service bulletin
  2016-06-08 · Engine And Engine Cooling — Exhaust System — Emission Control — Gas Recirculation Valve (Egr Valve)
• TSB: Some 2011 ? 2016 model year CT 200h (2ZR-FXE equipped) vehicles may exhibit a ?runs rough? and/or MIL ?ON? condition with DTC(s) P0300, P0301, P0302, P0303, and P0304 (Misfire) during light acceleration while the Exhaust Gas Recirculation (EGR) system is active. This condition can be caused by clogged EGR ports in the Intake Manifold Assembly. If the EGR ports are clogged, then replace the i
• L-SB-0174-17 Service bulletin
  2017-11-10 · Engine
• TSB: Some 2013 ? 2016 model year CT 200h vehicles may exhibit a vibration due to a rough idle and/or tapping noise from the HV transaxle after cold soak. The check engine light may also illuminate with Diagnostic Trouble Codes (DTCs) P0300, P0301, P0302, P0303, or P0304 (Random/Multiple Cylinder Misfire Detected). The Engine Control Module/ECM (SAE Term: Powertrain Control Module/PCM) logic has be
• LSB004419 Service bulletin
  2023-02-15 · Engine And Engine Cooling
• TSB: Some 2016 ? 2019 model year RX 450h and 2018 ? 2019 model year RX 450hL vehicles may exhibit a MIL ON condition with one or more of the following Diagnostic Trouble Codes (DTCs): ?P0301 ? Cylinder 1 Misfire Detected ?P0302 ? Cylinder 2 Misfire Detected ?P0303 ? Cylinder 3 Misfire Detected ?P0304 ? Cylinder 4 Misfire Detected ?P0305 ? Cylinder 5 Misfire Detected ?P0306 ? Cylinder 6

A stored code names the test that failed, never the part that caused it. The record above is what Lexus and its owners have filed about it; the code’s page across every make has the whole file.