Toyota Celica 2005 Repair Manual page 226

13. CHECKING MONITOR STATUS
NOTICE:
The monitor status (mode 6) is not applicable to the heated oxygen sensor (HO2S). However, HO2S
test values can be checked by O2S TEST RESULT (mode 5). Refer to step 12.
(a) Outline
The monitor results and the test values can be checked with the OBDII scan tool.
The engine control module (ECM) monitors the emissions−related components as the thermostat, cat-
alyst converter and evaporative emissions (EVAP), and determines whether they are functioning nor-
mally or not. When finished monitoring, the ECM stores the monitor results and the test values.
The monitor result indicates whether the component is functioning normally or not. The test value is
the value that was used to determine the monitor result. If the test value is outside the test limit (mal-
function criterion), the ECM determines the component is malfunctioning. Some emissions−related
components have multiple test values to determine monitor result. If one of these test values is outside
test limit, the ECM determines the component is malfunctioning.
(b) Description
The test value and test limit information are described as shown in the following table. This information
is included under "MONITOR RESULT" in the emissions−related DTC sections:
TID $08: Thermostat
TLT CID Unit Conversion
$01 Multiply by 0.625 and
1
subtract 40 [°C]
TID (Test Identification Data) is assigned to each emissions−related component.
S
TLT (Test Limit Type):
S
If TLT is 0, the component is malfunctioning when the test value is higher than the test limit.
If TLT is 1, the component is malfunctioning when the test value is lower than the test limit.
CID (Component Identification Data) is assigned to each test value.
S
Unit Conversion is used to calculate the test value indicated on generic OBDII scan tools.
S
2005 CELICA (RM1131U)
DIAGNOSTICS −
Description of Test Value
ECT sensor output when estimated ECT
has reached to malfunction criterion
225
ENGINE (1ZZ−FE)
Malfunction criterion for thermostat
Description of Test Limit
DI−27