SAAB WIS ONLINE

DTC P0301 CYLINDER 1 MISFIRE DETECTED

DTC P0301 CYLINDER 1 MISFIRE DETECTED

OUTLINE OF DIAGNOSIS

Detect whether the misfire occurred or not. (Revolution fluctuation method) Monitoring the misfire which influences exhaust deterioration (1.5 times of FTP) and catalyst damage is made obligatory by the law. Misfire affecting these two has three patterns below.


Intermittent misfire (The same cylinder misfires in random, or different cylinders misfire in random.): FTP 1.5 times misfire

Every time misfire (The same cylinder misfires every time.): FTP 1.5 times misfire, Catalyst damage misfire


The following detecting methods are adopted for these detection.

Intermittent misfire: FTP 1.5 times misfire


180° Interval Difference Method (MT: 1,800 rpm or less; AT: None)

360° Interval Difference Method (whole range)

720° Interval Difference Method (3,000 rpm or less)


Every time misfire: FTP 1.5 times misfire, Catalyst damage misfire


360° Interval Difference Method


ENABLE CONDITION

Secondary Parameters Enable Conditions
All secondary parameter enable conditions

More than 1 second

Intake manifold pressure change during 0.5 engine rev.

< 13.3 kPa (100 mmHg, 3.94 inHg)

Engine speed change

< 700 rpm/32 milliseconds

Throttle position change during 16 milliseconds

< 21°

Fuel shut-off function

Not operating

Atomospheric pressure

≥ 75.0 kPa (563 mmHg, 22.2 inHg)

Fuel level

≥ 9.0 litres (2.38 US gal, 1.98 Imp gal)

AT torque control

Not in operation

Evaporative system leak check

Not in operation

Engine speed

460 — 6200 rpm

Intake manifold pressure

> Map 3

Battery voltage

≥ 8 V

Conclusion of fuel parameter

Not supervolatile



Map3

MT (Vehicle Speed < 64.4 km/h (40 MPH))

rpm 700 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500
kPa (mmHg, inHg)

24.8 (186, 7.32)

21.3 (160, 6.30)

20.5 (154, 6.06)

20.9 (157, 6.18)

20.5 (154, 6.06)

21.9 (164, 6.46)

24.3 (182, 7.17)

26.1 (196, 7.72)

28.7 (215, 8.46)

30.8 (231, 9.09)

34.7 (260, 10.23)

38.5 (289, 11.38)

40.1 (301, 11.85)



MT (Vehicle Speed ≥ 64.4 km/h (40 MPH))

rpm 700 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500
kPa (mmHg, inHg)

40.0 (300, 11.81)

40.0 (300, 11.81)

33.6 (252, 9.92)

34.2 (257, 10.11)

33.5 (251, 9.88)

35.6 (267, 10.51)

34.7 (260, 10.24)

27.7 (208, 8.19)

28.7 (215, 8.46)

30.8 (231, 9.09)

34.7 (260, 10.23)

38.5 (289, 11.38)

40.1 (301, 11.85)



AT

rpm 700 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500
kPa (mmHg, inHg)

26.0 (195, 7.68)

23.3 (175, 6.89)

22.3 (167, 6.57)

22.8 (171, 6.73)

22.7 (170, 6.69)

24.0 (180, 7.09)

27.9 (209, 8.23)

30.0 (225, 8.86)

31.7 (238, 9.37)

35.2 (264, 10.39)

40.0 (300, 11.81)

44.4 (333, 13.11)

45.7 (343, 13.50)



GENERAL DRIVING CYCLE


Detecting misfire between idling and high revolution.

Perform the diagnosis continuously.


DIAGNOSTIC METHOD

When the misfire occurred, the engine speed is decreased and the crankshaft position speed will change. Calculate the interval difference value (diagnostic value) from crankshaft position speed by the following formula, and judge whether the misfire occurs or not comparing the calculated result with judgment value. Counting the number of misfire up, and if the misfire ratio is higher during 1000 rev. or 200 rev., judge NG for the corresponding cylinder.

Calculate the diagnostic value (from crankshaft position speed)



Misfire detection every single ignition (Compare diagnostic value with judgment value)


180° Interval Difference Method

360° Interval Difference Method

720° Interval Difference Method




NG judgment (Judge misfire occurrence required by the law) (Compare number of misfire with judgment)


FTP1.5 times misfire NG judgment

Catalyst damage misfire NG judgment




As the following figure, pick out a random cylinder as the standard and name it omg 0. And the former crankshaft position speed is named omg 1, the second former crankshaft position speed is named omg 2, the third is named omg 3, and the following is the same.


(A)

Ignition order

(B)

Crankshaft position speed



180° Interval Difference Method

Diagnosis value

domg 180 = (omg −1 omg 0) − (omg 5 − omg 1)/4

Judge misfire occurs in the following cases.


domg 180 > judgment value of positive side



domg 180 ≤ judgment value of negative side

(judgment value before 180°CA)





360° Interval Difference Method

Diagnosis value domg 360 = (omg 1 − omg 0) − (omg 3 − omg 2)
Misfire judgment

domg 360 > judgment value



Misfire occurs




720° Interval Difference Method

Diagnosis value domg 720 = (omg 1 − omg 0) − (omg 5 − omg 4)
Misfire judgment

domg 720 > judgment value



Misfire occurs




FTP 1.5 times misfire (Misfire occurrence level affecting exhaust gas)

Judgment Value (Judge that malfunction occurs when the misfire ratio is high in 1000 engine revs.)

Malfunction Criteria Threshold Value
FTP emission judgment value

> 1.0% in 1000 revs.



Time Needed for Diagnosis: 1000 engine revs.

Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous driving cycles.

Catalyst damage misfire (Misfire occurrence level damaging catalyst)

Judgment Value (Judge that malfunction occurs when the misfire ratio is high in 200 engine revs. (400 ignitions))

Malfunction Criteria Threshold Value
Catalyst damage misfire judgment value

See Map 1



Map 1 Fault criteria threshold for misfire which would result in catalyst damage


These figures mean the misfire ratio (%) in 400 ignitions; for example, 22.5 (%) means 400 (ignition) × 22.5 (%) = 90 (ignition) or more, so this case is judged misfire.

Time Needed for Diagnosis: 200 engine revs.

Malfunction Indicator Light Illumination: Illuminates as soon as the malfunction occurs.

DTC CLEAR CONDITION


When the OK idling cycle was completed 40 times in a row

When “Clear Memory” was performed


MALFUNCTION INDICATOR LIGHT CLEAR CONDITION


When the OK driving cycle was completed 3 times in a row

When “Clear Memory” was performed


FAIL SAFE

None

ECM OPERATING AT DTC SETTING

Memorize the freeze frame data. (For test mode $02)