Codes 21 & 28 - Main O2 Sensor Signal Left Or Right Bank

WARNING: This page is about a different car, the 1995 Lexus SC 400. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: After repairs are completed, perform TROUBLE CODE DETECTION DRIVING PATTERN TEST at end of testing for this trouble code.

Fig 1: Codes 21 & 28 Flow Chart (1 Of 2) Main O2 Sensor Signal Left Or Right Bank

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 2: Codes 21 & 28 Flow Chart (2 Of 2) Main O2 Sensor Signal Left Or Right Bank

Fig 3: Code 21 & 28 Diagnostic Trouble Code Detection Test Main O2 Sensor Signal Left Or Right Bank