05−146
− DIAGNOSTICSSFI SYSTEM (2AZ−FSE)
AVENSIS Supplement (RM1045E)
DTC P0300 RANDOM/MULTIPLE CYLINDER MISFIRE
DETECTED
DTC P0301CYLINDER1MISFIRE DETECTED
DTC P0302 CYLINDER 2 MISFIRE DETECTED
DTC P0303 CYLINDER 3 MISFIRE DETECTED
DTC P0304 CYLINDER 4 MISFIRE DETECTED
CIRCUIT DESCRIPTION
When a misfire occurs in the engine, hydrocarbons (HC) enter the exhaust in high concentrations. If this HC
concentration is high enough, there could be an increase in exhaust emissions levels. High concentrations
of HC can also cause to temperature of the catalyst to increase, possibly damaging the catalyst. To prevent
this increase in emissions and limit the possibility of thermal damage, the ECM monitors the misfire rate.
When the temperature of the catalyst reaches a point of thermal degradation, the ECM will blink the CHK
ENG. For monitoring misfire, the ECM uses both the camshaft position sensor and the crankshaft position
sensor. The camshaft position sensor is used to identify misfiring cylinders and the crankshaft position sen-
sor is used to measure variations in the crankshaft rotation speed. The misfire counter increments when
crankshaft rotation speed variations exceed threshold values.
If the misfiring rate exceeds the threshold value and could cause emissions deterioration, the ECM illumi-
nates the CHK ENG.
HINT:
SFor any particular 200 revolutions of the engine, misfiring which would result in overheating of catalyst
is detected. This cause CHK ENG to blink (1trip detection logic).
SFor any particular1,000 revolutions of the engine, misfiring which would result in a deterioration of
emissions is detected. This illuminates CHK ENG (2 trip detection logic).
05HII−01
05–118
– DIAGNOSTICSSFI SYSTEM (1ZZ–FE/3ZZ–FE)(From February, 2004)
AVENSIS REPAIR MANUAL SUPPLEMENT
(RM1098E)
DTC P0300 RANDOM/MULTIPLE CYLINDER MISFIRE
DETECTED
DTC P0301 CYLINDER 1 MISFIRE DETECTED
DTC P0302 CYLINDER 2 MISFIRE DETECTED
DTC P0303 CYLINDER 3 MISFIRE DETECTED
DTC P0304 CYLINDER 4 MISFIRE DETECTED
CIRCUIT DESCRIPTION
When a misfire occurs in the engine, hydrocarbons (HC) enter the exhaust gas in high concentrations. If this
HC concentration is high enough, there could be an increase in exhaust emission levels. High concentra-
tions of HC can also cause temperature of the catalyst to increase, possibly damaging the catalyst. To pre-
vent this increase in emissions and limit the possibility of thermal damage, the ECM monitors the misfire rate.
When the temperature of the catalyst reaches a point of thermal degradation, the ECM will blink the MIL.
For monitoring misfire, the ECM uses both the camshaft position sensor and the crankshaft position sensor.
The camshaft position sensor is used to identify misfiring cylinders and the crankshaft position sensor is used
to measure variations in the crankshaft rotation speed. The misfire counter increments when crankshaft rota-
tion speed variations exceed threshold values.
If the misfiring rate exceeds the threshold and could cause emission deterioration, the ECM illuminates the
MIL.
HINT:
For any particular 200 revolutions of the engine, misfiring which could result in overheating of the cata-
lyst is detected. This will cause the MIL to blink (1 trip detection logic).
For any particular 1,000 revolutions of the engine, misfiring which could result in emission deterioration
is detected. This will cause the MIL to illuminate (2 trip detection logic).
05KOH–02
