Toyota Celica 2005, Repair Manual

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A21762
A − A Section
Air
Solid Electrolyte
(Zirconia Element)
Platinum Electrode
Heater
Exhaust Gas
Cover
Ideal Air − Fuel Mixture
Output V
oltage
Richer − Air Fuel Ratio − Leaner
Element
A
A
DI − 112
− DIAGNOSTICS ENGINE (1ZZ − FE)
2005 CELICA (RM1131U)
DTC P0130 Oxygen Sensor Circuit (Bank 1 Sensor 1)
CIRCUIT DESCRIPTION
The heated oxygen sensor is used to monitor oxygen concentration in the exhaust gas. For optimum catalyt-
ic converter operation, the air fuel mixture must be maintained near the ideal stoichiometric ratio. The heated
oxygen sensor output voltage changes suddenly in the vicinity of the stoichiometric ratio. The ECM adjusts
the fuel injection time so that the air
− fuel ratio is nearly stoichiometric.
When the air − fuel ratio becomes LEAN, the oxygen concentration in the exhaust gas increases. And the
heated oxygen sensor informs the ECM of the LEAN condition (low voltage, i.e. less than 0.45 V).
When the air
− fuel ratio is richer than the stoichiometric air − fuel ratio, the oxygen will be vanished from the
exhaust gas. And the heated oxygen sensor informs the ECM of the RICH condition (high voltage, i.e. more
than 0.45 V).
DTC No. DTC Detection Condition Trouble Area
P0130
Output voltage of heated oxygen sensor remains at 0.4 V or
more, or 0.5 V or less, during idling after engine is warmed up
(2 trip detection logic)
S Open or short in heated oxygen sensor (bank 1 sensor 1)
circuit
S Heated oxygen sensor (bank 1 sensor 1)
S Heated oxygen sensor heater (bank 1 sensor 1)
S EFI relay
S Air induction system
S Fuel pressure
S Injector
S ECM
HINT:
S
Sensor 1 is the sensor closest to the engine assembly.
S
The output voltage of the heated oxygen sensor and the short − term fuel trim value can be read using
the hand − held tester or the OBD ll scan tool.
DIC6O − 02
310