Toyota Celica 2005 Repair Manual page 312

MONITOR DESCRIPTION
Rich
0.55
0.45
0.40
Lean
The ECM uses the heated oxygen sensor information to regulate the air−fuel ratio to be close to a stoichio-
metric ratio. This maximizes the catalytic converter's ability to purify the exhaust gas. The sensor detects
oxygen level in the exhaust gas and sends this signal to the ECM.
The inner surface of the sensor element is exposed to outside air. The outer surface of the sensor element
is exposed to exhaust gas. The sensor element is made of platinum coated zirconia and includes an inte-
grated heating element. The heated oxygen sensor has the characteristic whereby its output voltage
changes suddenly in the vicinity of the stoichiometric air−fuel ratio. The heated oxygen sensor generates
output voltage between 0 V and 1.0 V in response to the oxygen concentration in exhaust gas. When the
output voltage of the heated oxygen sensor is 0.55 V or more, the ECM judges that the air−fuel ratio is RICH.
When it is 0.4 V or less, the ECM judges that the air−fuel ratio is LEAN.
Under normal condition, the output voltage from the heated oxygen sensor alternates RICH and LEAN sides
periodically. If the heated oxygen sensor outputs RICH signal (or LEAN signal) constantly, or if the heated
oxygen sensor cannot output enough voltage to reach the minimum specification, the ECM interprets this
as a malfunction in the heated oxygen sensor and sets a DTC.
MONITOR STRATEGY
Related DTCs
Required sensors/components
Frequency of operation
Duration
MIL operation
Sequence of operation
2005 CELICA (RM1131U)
DIAGNOSTICS −
PASS
Pass / Fail definition of voltage malfunction
P0130
Main sensors/components
Related sensors/components
Once per driving cycle
20 to 36 sec. x (3 times)
2 driving cycles
None
311
ENGINE (1ZZ−FE)
FAIL
FAIL
FAIL
Front heated oxygen sensor voltage is constant
at lean side or rich side
Front heated oxygen senor
Crank position sensor, Vehicle speed sensor
DI−113
Time
A20806