Misfire Monitor

OBD System Description - Misfire Monitor

Random/Multiple Cylinder Misfires detected
DTC
P0300 Refer to DTC P0300: Engine Misfire Detected. P0300

MONITOR STRATEGY DESCRIPTION
CARB A misfire failure criteria:
Risk of catalyst damage, monitoring interval over 200 crankshaft revolutions.
CARB B1 misfire failure criteria:
Emission increase, monitoring interval over the first 1,000 crankshaft revolutions. CARB B4 misfire failure criteria:
Emission increase, monitoring interval over 1,000 crankshaft revolutions. For errors detection, misfire must take place for 4 monitoring intervals.
(after the first 1,000 crk revolutions)

MALFUNCTION CRITERIA AND THRESHOLD VALUE(S)
Monitoring during the 200 crankshaft revolutions:
The cylinder-specific counters are monitored each cycle.
If the single cylinder misfire detected over a critical threshold 700.
If the threshold is reached outside of the FTP cycle, the concerning cylinder is shut off immediately. CARB A misfire criterion is confirmed, else the criterion will be evaluated at the end of the 200 crankshaft revolution window (in this case, the cylinder will be shut off only after (3) A windows).
When an error is set, MIL is blinking or ON.
Misfire Cylinder Limp Home Process:
Cylinder shut off is limited by a maximum number of cylinders (1) that can be shut-off simultaneously each time, the misfire cylinder limp home process on one (or more) cylinder(s) is triggered, the corresponding cylinder counter(s) is (are) unitary incremented.
Monitoring at the end of 200 crankshaft revolutions:
If the global sum of detected misfire is greater than the threshold 4,200, the cylinder with the highest misfire rate is determined.
RPM < 4,500 rpm
Load percentage is < 70.999%
And Counter is > 700
Then engine criteria is in the FTP region.
At the end of first 1,000 crankshaft revolutions:
If the sum of detected misfire is greater than threshold 44, misfire cylinder limp home process is activated.
At the end of (other than first) 1,000 crankshaft revolutions:
If the sum of detected misfire is greater than threshold 44 during four monitoring intervals, cylinder limp home process is activated.

SECONDARY PARAMETERS AND ENABLE CONDITIONS
Enable Conditions for MISFIRE Diagnosis:
Ignition "ON", Eng "ON"
No CRK error
No CAM error
No MAF error
No MAF/TPS error
No TPS error

TIME LENGTH AND FREQUENCY
Every segment

Individual Misfire Cylinders #1 - 6
DTC
P0301 Refer to DTC P0301: Cylinder 1 Misfire Detected. P0301
P0302 Refer to DTC P0302: Cylinder 2 Misfire Detected. P0302
P0303 Refer to DTC P0303: Cylinder 3 Misfire Detected. P0303
P0304 Refer to DTC P0304: Cylinder 4 Misfire Detected. P0304
P0305 Refer to DTC P0305: Cylinder 5 Misfire Detected. P0305
P0306 Refer to DTC P0306: Cylinder 6 Misfire Detected. P0306

MONITOR STRATEGY DESCRIPTION
During Misfire A monitoring process, if the number of detected misfire on a single cylinder is over the threshold of short term catalyst protection, Misfire cylinder limp home is activated, and Misfire "A" errors is confirmed.
At each end of Misfire A, B1, or B4 monitoring intervals, if the misfire errors is confirmed for the interval, the cylinder with the highest misfire rate is determined.

MALFUNCTION CRITERIA AND THRESHOLD VALUE(S)
During the Misfire A monitoring window:
If the global sum of detected misfire is greater than the threshold 4,200, misfire cylinder limp home process is activated.
At the end of Misfire A monitoring window:
If misfire A criteria is confirmed, and the number of detected misfire on a cylinder is over the
threshold (4,000).
The errors is stored and MIL = BLINKING (100 ms) and if the errors occurs in the next DC, MIL =
ON
RPM < 4,500 rpm,
Load percentage is < 79.999%
And
Counter is > 700
=> Then engine criteria is in the FTP region.
At the end of Misfire B1/B4 window:
Misfire B1/B4 criteria is confirmed, and the number of detected misfire on a cylinder is over the threshold, misfire cylinder limp home process is activated:
=> The errors is stored and MIL = ON
CARB B misfire sum (global) > 44%

SECONDARY PARAMETERS AND ENABLE CONDITIONS
During the Misfire A monitoring window:
Enable Conditions for MISFIRE Diagnosis:
Ignition "ON", Eng "ON"
No CRK error
No CAM error
No MAF error
No MAF/TPS error
No TPS error
At the end of Misfire B1/B4 window:
Enable Conditions for MISFIRE Diagnosis:
Ignition "ON", Eng "ON"
No CRK error
No CAM error
No MAF error
No MAF/TPS error
No TPS error

TIME LENGTH AND FREQUENCY
Every segment

Misfire Detection-segment Time Acquisition Incorrect
DTC
P1321 Refer to DTC P1321: Misfire Segment Time Acquisition Incorrect. P1321

MONITOR STRATEGY DESCRIPTION
The purpose is to diagnose the ER segment adaptive values.
If during or at the end of the segment adaptive values learning process at least one of the engine roughness segment adaptation values is at the limit the error symptom "engine roughness segment adaptation values at the limit" is detected.

MALFUNCTION CRITERIA AND THRESHOLD VALUE(S)
|ER filtered adaptive values used for learning process (for each segment)| >= 4.99% (Limitation of ER segment adaptation range (mechanical tolerance).) Then an error is detected.

SECONDARY PARAMETERS AND ENABLE CONDITIONS
Enable Conditions:
ER segment adaptation process enable = 1
=> 0 and
Diagnosis condition mode of ER segment time adaptive values = 0
Or
ER segment adaptation process enable = 1
And
Diagnosis condition mode of ER segment time adaptive values = 1
No crk error detected
No cam error detected

TIME LENGTH AND FREQUENCY
Segment task