Misfire Monitor

OBD System Description - Misfire Monitor

Misfire

DTC Description / Detecting Condition / Confirmation Procedure
P0300 (Misfire) refer to DTC P0300: Engine Misfire Detected. P0300
P0301 (Misfire Cyl 1) refer to DTC P0301: Cylinder 1 Misfire Detected. P0301
P0302 (Misfire Cyl 2) refer to DTC P0302: Cylinder 2 Misfire Detected. P0302
P0303 (Misfire Cyl 3) refer to DTC P0303: Cylinder 3 Misfire Detected. P0303
P0304 (Misfire Cyl 4) refer to DTC P0304: Cylinder 4 Misfire Detected. P0304

Monitor Strategy Description
These DTC will determine if a multiple cylinder misfire or a cylinder specific misfire is occurring by monitoring crankshaft acceleration.

Malfunction Criteria
A: Individual event misfire detection See broken web link.
B: Emissions damaging > See broken web link.
C: Catalyst damaging > See broken web link. X misfires in 600 events (based on RPM and Load)

Enable Conditions
A:
Misfire Not Delayed (No active delays) = 0 engine cycles
AND All delays expired (Misfire Delay Counter = 0) = 0
B:
Engine load and engine speed is in a non-detectable region =/= TRUE
AND Time since detectable region entered >= 10 engine cycles
C:
Flare up and Flare down No-Delay Period
Engine Run time < 10 s
AND Engine Load >= See broken web link.

AND Time since negative torque conditions entered >= 15 engine cycles
Vehicle Operator Induced Actions = FALSE boolean
Cam Error
Cam Error Present = FALSE
AND Time since cam error removed > 30 engine cycles
Intrusive Diagnostics
Intrusive diagnostics active (EGRFLOW) = FALSE
Time since intrusive diagnostic became inactive >= 31 engine cycles
Low Fuel Level
Fuel Level > 0.15%
AND Fuel Level Fault = FALSE
AND Vehicle in plant = FALSE
AND Time since low fuel conditions met >= 500 engine cycles
All cylinders fueled
Number of cylinders fueled = 4
AND Fuel Cut Off = FALSE
AND DFCO = FALSE
AND High Vehicle Speed Fuel Shut Off = FALSE
AND High RPM Fuel Shut Off = FALSE
AND Time since all cylinders fueled >= 16 engine cycles
Delta Throttle
Current Throttle Position > Previous Throttle
AND Delta Throttle Position > 9.5001%
AND Time since throttle delta occurred >= 0 engine cycles
Current Throttle Position < Previous Throttle
AND Delta Throttle Position > 14.9994%
AND Time since throttle delta occurred >= 0 engine cycles
Abusive Engine Speed
Engine Speed >= 6,750 rpm (For AT), 7,000 rpm (For MT)
AND Time since engine speed exceedance occurred > 4,999 engine cycles
Crankshaft speed patterns normal
Run Time >= 10 sec.
AND Consecutive Positive Crank Delta < 15 events
AND Time since Consecutive Positive conditions occurred >= 0 engine cycles
OR
Consecutive Negative Crank Delta < 15 events
AND Time since Consecutive Negative conditions occurred >= 0 engine cycles
Flare up and Flare down No-Delay Period
Run Time < 10 sec.
AND Consecutive Positive Crank Delta < 22.5 events
AND Time since Consecutive Positive conditions occurred >= 0 engine cycles
OR
Consecutive Negative Crank Delta < 22.5 events
AND Time since Consecutive Negative conditions occurred >= 0 engine cycles
Engine Speed Range
Run time >= 10 sec.
AND Engine Speed < 6,250 rpm (For AT), 6,500 rpm (For MT)
AND Engine Speed > 600 rpm
AND Time since engine speed conditions met >= 15 engine cycles
Ignition Voltage
Run Time >= 10 sec.
AND Ignition Voltage > 10.9936 V
AND Ignition Voltage < 15.9907 V
AND Time since ignition voltage conditions met >= 15 engine cycles
Coolant Temperature
Start up Coolant Temperature < -7
AND Coolant Temperature > 21
ELSE Else if (Coolant temperature > -7
AND Coolant temperature) < 120
AND Time since delay enabled >= 15 engine cycles
Disabling faults present / Disabling Active Faults
=/= P0340 / P0016 / P0118 / P0117 / P0116 / P0335 / P0336 / P2110 / 0108 / P0107 / P0106 / P0502
Vehicle Operator Induced Actions
Run Time < 10 sec.
AND Engine Load < = See broken web link.
AND Engine Speed < 1,500 rpm
AND Time since action completed >= 15 engine cycles

Time required
Time Length and Frequency:
B:
Emissions damaging: 7 misfires in 5 out of 16,100 engine cycle analysis blocks, 4 times. See broken web link.
C:
Catalyst damaging: # of misfires (See table above.) based on RPM and Load in 1 out of 16,100 engine cycle analysis blocks more than 3 times inside FTP conditions (misfire % load <= 75 AND RPM <= 3,200 rpm) or just once (1. outside FTP conditions. See broken web link.

























Table B