LEMON Manuals
: Even more car manuals for everyone: 1960-2025
Home
>>
Toyota
>>
1989
>>
Corolla LE, Automatic
>>
Repair and Diagnosis
>>
Engine Performance
>>
System
>>
Tests W/Codes
>>
Code 21 - O2 Sensor Signal (4A-F)
>>
Probable Causes
April 5, 2026:
LEMON Manuals is launched!
Read the announcement.
Probable Causes
Oxygen Sensor or Sensor Circuit
ECU
NOTE:
Diagnostic chart not available from manufacturer.