Toyota 1 MZ–FE Manual page 493

DTC P0300 Random Misfire Detected
DTC P0301 P0302 P0303 P0304 P0305 P0306 Misfire
Detected (Cylinder 1–6)
CIRCUIT DESCRIPTION
Misfire: The ECM uses the crankshaft position sensor and camshaft position sensor to monitor changes
in the crankshaft rotation for each cylinder.
The ECM counts the number of times the engine speed change rate indicates that misfire has occurred.
And when the misfire rate equals or exceeds the count indicating that the engine condition has deterio-
rated, the MIL lights up.
If the misfire rate is high enough and the driving conditions will cause catalyst overheating, the MIL blinks
when misfiring occurs.
Diagnostic Trouble Code Detecting Condition
DTC No.
Misfiring of multiple cylinders is detected during the
P0300
same 200 or 1,000 revolutions.
P0301
For each 200 revolutions of the engine, misfiring is
detected which can cause catalyst overheating.
P0302
(This causes MIL to blink)
P0303
P0304
For each 1,000 revolutions of the engine, misfiring is
detected which causes emissions deterioration.
P0305
(2 trip detection logic)
P0306
HINT; When the code for a misfiring cylinder is recorded repeatedly but no Random Misfire code is
recorded, it indicates that the misfires were detected and recorded at different times.
1MZ–FE ENGINE – CIRCUIT INSPECTION
Trouble Area
Ignition system
Injector
Fuel line pressure
EG R
Compression pressure
Valve clearance not to specification
Valve timing
Mass air flow meter
Engine coolant temp. sensor
EG2–493