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

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

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

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

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