LEMON Manuals
: Even more car manuals for everyone: 1960-2025
Home
>>
Toyota
>>
2003
>>
Matrix Base, FWD, Standard
>>
Repair and Diagnosis (Single Page)
>>
Engine Performance
>>
Testing & Diagnosis
>>
Engine Control System Self Diagnostics
>>
Diagnostic Tests
>>
DTC P0128: Thermostat Malfunction (Matrix Model)
>>
Possible Causes
April 5, 2026:
LEMON Manuals is launched!
Read the announcement.
Possible Causes
Defective thermostat.
Defective cooling fan operation.
Defective cooling system.
Defective ECM.