Diagnostic Trouble Code (Dtc) P0301 Random/Multiple Cylinder Misfire Detected - Isuzu 1999 RODEO Workshop Manual

DIAGNOSTIC TROUBLE CODE (DTC) P0301 RANDOM/MULTIPLE CYLINDER
Circuit Description
If the PCM determines that the engine is misfiring and can
determine the actual cylinder that is misfiring then it will
log the individual trouble code for that cylinder P0301.
This is normally the situation in the case of a failed fuel
injector, spark plug or ignition lead.
Conditions for Setting the DTC
f None of the following Diagnostic Trouble Codes are
present: TP sensor, MAP sensor, CMP sensor, VSS,
ECT, CKP sensor.
f The engine speed is between 600 and 6250 RPM.
f The system voltage is between 11 and 16 volts.
f The engine coolant temperature sensor (ECT)
indicates an engine temperature between –6.75°C
(20°F) and 120°C (248°F).
f Throttle angle is steady and throttle angle changes less
than 2.73% per 100 milliseconds.
f The PCM detects a crankshaft RPM variation
indicating a misfire that is sufficient to cause catalytic
converter damage or emissions levels to exceed the
mandated standard.
f TP sensor reads less than 3.125%.
f Vehicle speed is greater than 33km/h (20mph).
f Engine under load.
RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION
MISFIRE DETECTED
Action Taken When the DTC Sets
f The PCM will illuminate the malfunction indicator lamp
(MIL) the first time the fault is detected.
f If the misfire is severe enough to cause possible
catalyst damage, the PCM will flash the MIL for as long
as the misfire remains at catalyst damaging levels.
f "Open Loop" fuel control will be in effect.
f The PCM will store conditions which were present
when the Diagnostic Trouble Code was set as Freeze
Frame and in the Failure Records data.
Conditions for Clearing the MIL/DTC
f The PCM will turn the MIL OFF on the third consecutive
trip cycle during which the diagnostic has been run and
the fault condition is no longer present.
f A history Diagnostic Trouble Code P0301 will clear
after 40 consecutive warm–up cycles have occurred
without a fault.
f Diagnostic Trouble Code P0301 can be cleared by
using the Scan Tool's "Clear Info" function.
Diagnostic Aids
The Tech 2 displays "Misfire Cur. # 1 through #4" can be
useful to determine whether the misfire is isolated to a
single cylinder.
f Damaged or faulty ignition coils – Check for cracks or
other damage.
6E1–195
D06RX050