DTC P0171 Or DTC P0172 & DTC P0174 Or DTC P0175: Notes

WARNING: This page is about a different car, the 2002 Lexus ES 300. However, it is still accessible from the selected car via links, so may be relevant.

Code Definition

DTC P0171 Or DTC P0172: System Too Lean/Rich Bank No. 1
DTC P0174 Or DTC P0175: System Too Lean/Rich Bank No. 2

CAUTION: If ECM replacement is instructed in following testing, always ensure ECM connectors and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. If ECM is replaced, ECM must be programmed with proper ignition key code for engine immobilizer system. For programming procedures, see COMPUTER RELEARN PROCEDURES - IMPORT article in GENERAL INFORMATION, or appropriate ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT.

NOTE: Bank 1 is also known as right bank (RH). A/F sensor refers to sensor closest to engine block.

NOTE: For component location, see appropriate illustration in THEORY & OPERATION article.