Toyota Celica 2005 Repair Manual page 331

DI−132
DTC P0134
CIRCUIT DESCRIPTION
Refer to DTC P0130 on page DI−112.
DTC No.
After engine is warmed up, heated oxygen sensor (bank 1, 2
sensor 1) output does not indicate RICH (y0.45 V) even once
when conditions (a), (b), (c) and (d) continue for at least 65
sec.:
P0134
(a) Engine speed: 1,400 rpm or more
(b) Vehicle speed: 40 to 130 km/h (25 to 81 mph)
(c) Throttle valve is not fully closed
(d) 180 sec. or more after starting engine
HINT:
After confirming DTC P0134, check the output voltage of the heated oxygen sensor (bank 1 sensor 1) in the
"DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL" using the hand−held tester or the OBD II scan tool.
If the output voltage of the heated oxygen sensor is always less than 0.1 V, the sensor circuit may be open
or shorted.
MONITOR DESCRIPTION
The ECM uses the heated oxygen sensor to optimize the air−fuel mixture in closed−loop fuel control. This
control helps decrease exhaust emissions by providing the catalyst with a nearly stoichiometric mixture.
The sensor detects the oxygen level in the exhaust gas and the ECM uses this data to control the air−fuel
ratio. The sensor output voltage ranges from 0 V to 1 V. If the signal voltage is less than 0.4 V, the air−fuel
ratio is LEAN. If the signal voltage is more than 0.55 V, the air−fuel ratio is RICH. If the conditions for the
closed−loop fuel control are met and after a specified time−period, the sensor's output signal never indicates
RICH, the ECM will conclude that the closed−loop fuel control is malfunctioning. The ECM will illuminate the
MIL and a DTC will be set.
MONITOR STRATEGY
Related DTCs
Required sensors/components
Frequency of operation
Duration
MIL operation
Sequence of operation
2005 CELICA (RM1131U)
DIAGNOSTICS
Oxygen Sensor Circuit No Activity Detected
(Bank 1 Sensor 1)
DTC Detecting Condition
Main sensors/components
Related sensors/components
Once per driving cycle
65 sec.
1 driving cycle
None
− ENGINE (1ZZ−FE)
S Open or short in heated oxygen sensor (bank 1 sensor 1)
circuit
S Heated oxygen sensor (bank 1 sensor 1)
S EFI relay
S Air induction system
S Fuel pressure
S Injector
S Gas leakage in exhaust system
S ECM
S PCV piping
P0134
330
Trouble Area
Excessive time to enter closed loop
Front heated oxygen sensor
Crank position sensor, Engine coolant tempera-
ture sensor, Vehicle speed sensor
DIC6Q−02