DIAGNOSTIC METHOD Subaru Outback BS

DIAGNOSTIC METHOD

Judge as NG when the conditions for the outline of the diagnosis of the top are established.

Note. For the detection standard, refer to DTC B1570 ANTENNA .

Note. For the detection standard, refer to DTC B1570 ANTENNA .

Note. For the detection standard, refer to DTC B1570 ANTENNA .

Note. For the detection standard, refer to DTC B1570 ANTENNA .

Note. For the detection standard, refer to DTC B1570 ANTENNA .

Note. For the detection standard, refer to DTC B1570 ANTENNA .

Note. For the detection standard, refer to DTC B1570 ANTENNA .

Detect the AVCS system malfunction.

Judge NG when the amount of AVCS actual timing advance does not approach to the amount of AVCS target timing advance.

When the differences of target timing advance amount and actual timing advance amount is calculated during AVCS control, and the difference per predetermined time is the specified value or larger.

1. Abnormality Judgment

Judge as NG when the following conditions are established within the predetermined time.

JUDGMENT VALUE

Time Needed for Diagnosis: 25000 ms

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

1. Normality Judgment

Judge as OK and clear the NG if the following conditions are established within the predetermined time.

JUDGMENT VALUE

Time Needed for Diagnosis: 25000 ms

Note. For the detection standard, refer to DTC P000A A CAMSHAFT POSITION SLOW RESPONSE (BANK 1) .

Detect open or short circuit of the oil control solenoid.

Judge as NG when the current is small even though the duty signal is large.

1. Abnormality Judgment

If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.

JUDGMENT VALUE

Time Needed for Diagnosis: 2000 ms

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

1. Normality Judgment

Judge as OK and clear the NG if the continuous time while the following conditions are established is more than the predetermined time.

JUDGMENT VALUE

Time Needed for Diagnosis: 2000 ms

Detect the AVCS system malfunction.

Judge as NG when the conditions during which the differences of AVCS target timing advance amount and AVCS actual timing advance amount is large continues.

When the conditions during which the differences of AVCS target timing advance amount and AVCS actual timing advance amount is large continues for certain amount of time.

1. Abnormality Judgment

Judge as NG when the following conditions are established within the predetermined time.

JUDGMENT VALUE

Time Needed for Diagnosis: 5000 ms

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

1. Normality Judgment

Judge as OK and clear the NG if the following conditions are established within the predetermined time.

JUDGMENT VALUE

Time Needed for Diagnosis: 5000 ms

Detect the AVCS system malfunction.

Judge as NG when standard timing advance amount is far from learning angle.

Judge as NG when the absolute value of the difference between cam signal input position and learning value is out of specification.

1. Abnormality Judgment

If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.

JUDGMENT VALUE

Time Needed for Diagnosis: 5000 ms

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

Note. Initial standard learning value is the value of crank angle initially input at the production plant. And then it will be updated every time normal judgment has been completed. Learning value will not be updated if NG judgment occurs because timing belt or chain derails suddenly in process or because wrong assembly occurs during servicing.

1. Normality Judgment

Judge as OK and clear the NG if the continuous time while the following conditions are established is more than the predetermined time.

JUDGMENT VALUE

Time Needed for Diagnosis: Less than 1 second

Note. For the detection standard, refer to DTC P0016 CRANKSHAFT POSITION - CAMSHAFT POSITION CORRELATION (BANK1) .

Note. For the detection standard, refer to DTC P0010 "A" CAMSHAFT POSITION ACTUATOR CIRCUIT/OPEN (BANK 1) .

Note. For the detection standard, refer to DTC P0011 INTAKE CAMSHAFT POSITION - TIMING OVER-ADVANCED OR SYSTEM PERFORMANCE (BANK 1) .

Detect functional errors of the front oxygen (A/F) sensor heater.

Judge as NG when it is determined that the front oxygen (A/F) sensor impedance is large when looking at engine status such as deceleration fuel cut.

Scheme 2

1. Abnormality Judgment

If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.

JUDGMENT VALUE

Time Needed for Diagnosis: 10000 ms

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

1. Normality Judgment

Judge as OK and clear the NG if the continuous time while the following conditions are established is more than the predetermined time.

JUDGMENT VALUE

Time Needed for Diagnosis: 10000 ms

Detect front oxygen (A/F) sensor heater open or short circuit.

The front oxygen (A/F) sensor heater performs duty control, and the output terminal voltage at ON is 0 V, and the output terminal voltage at OFF is the battery voltage.

Judge as NG when the terminal voltage remains Low.

Scheme 3

1. Abnormality Judgment

If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.

JUDGMENT VALUE

Time Needed for Diagnosis: 4 ms x 250 time(s)

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

1. Normality Judgment

Judge as OK and clear the NG if the continuous time while the following conditions are established is more than the predetermined time.

JUDGMENT VALUE

Time Needed for Diagnosis: Less than 1 second

Detect front oxygen (A/F) sensor heater open or short circuit.

The front oxygen (A/F) sensor heater performs duty control, and the output terminal voltage at ON is 0 V, and the output terminal voltage at OFF is the battery voltage.

Judge as NG when the terminal voltage remains High.

Scheme 4

1. Abnormality Judgment

If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.

JUDGMENT VALUE

Time Needed for Diagnosis: 4 ms x 500 time(s)

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

1. Normality Judgment

Judge as OK and clear the NG if the continuous time while the following conditions are established is more than the predetermined time.

JUDGMENT VALUE

Time Needed for Diagnosis: Less than 1 second

Detect the rear oxygen sensor heater open or short circuit.

The rear oxygen sensor heater performs duty control, and the output terminal voltage at ON is 0 V, and the output terminal voltage at OFF is the battery voltage.

Judge as NG when the terminal voltage remains Low.

Scheme 5

1. Abnormality Judgment

If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.

JUDGMENT VALUE

Time Needed for Diagnosis: 8 ms x 1250 time(s)

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

1. Normality Judgment

Judge as OK and clear the NG if the continuous time while the following conditions are established is more than the predetermined time.

JUDGMENT VALUE

Time Needed for Diagnosis: Less than 1 second

Detect the rear oxygen sensor heater open or short circuit.

The rear oxygen sensor heater performs duty control, and the output terminal voltage at ON is 0 V, and the output terminal voltage at OFF is the battery voltage.

Judge as NG when the terminal voltage remains High.

Scheme 6

1. Abnormality Judgment

If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.

JUDGMENT VALUE

Time Needed for Diagnosis: 8 ms x 1250 time(s)

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

1. Normality Judgment

Judge as OK and clear the NG if the continuous time while the following conditions are established is more than the predetermined time.

JUDGMENT VALUE

Time Needed for Diagnosis: Less than 1 second

Detect problems in the intake manifold pressure sensor output properties.

Judge as NG when the intake air pressure AD value is Low whereas it seemed to be High from the viewpoint of engine condition, or when it is High whereas it seemed to be Low from the engine condition.

Scheme 7

1. Abnormality Judgment

Judge as NG when Low side or High side becomes NG.

If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.

JUDGMENT VALUE

Time Needed for Diagnosis

Low side: 5000 ms

High side: 10000 ms

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

1. Normality Judgment

Judge as OK and clear the NG when both Low side and High side become OK.

If the duration of time while the following conditions are met is longer than the time indicated, judge as OK.

JUDGMENT VALUE

Time Needed for Diagnosis

Low side: Less than 1 second

High side: Less than 1 second

Detect the malfunction of air flow sensor output properties.

Judge as a low side NG when the air flow voltage indicates a small value regardless of running in a state where the air flow voltage increases. Judge as a high side NG when the air flow voltage indicates a large value regardless of running in a state where the air flow voltage decreases. Judge air flow sensor property NG when the Low side or High side becomes NG.

Scheme 8

1. Abnormality Judgment

Judge as NG when Low side or High side becomes NG.

If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.

JUDGMENT VALUE

Time Needed for Diagnosis

Low: 5000 ms

High: 10000 ms

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

1. Normality Judgment

Judge as OK and clear the NG when both Low side and High side become OK.

Judge as OK and clear the NG if the continuous time while the following conditions are established is more than the predetermined time.

JUDGMENT VALUE

Time Needed for Diagnosis

Low: Less than 1 second

High: Less than 1 second

Detect open or short circuits of the air flow sensor.

Judge as NG if out of specification.

Scheme 9

1. Abnormality Judgment

If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.

JUDGMENT VALUE

Time Needed for Diagnosis: 500 ms

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

1. Normality Judgment

Judge as OK and clear the NG if the continuous time while the following conditions are established is more than the predetermined time.

JUDGMENT VALUE

Time Needed for Diagnosis: Less than 1 second

Detect open or short circuits of the air flow sensor.

Judge as NG if out of specification.

Scheme 10

1. Abnormality Judgment

If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.

JUDGMENT VALUE

Time Needed for Diagnosis: 500 ms

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

1. Normality Judgment

Judge as OK and clear the NG if the continuous time while the following conditions are established is more than the predetermined time.

JUDGMENT VALUE

Time Needed for Diagnosis: Less than 1 second

Detect the open or short circuit of intake manifold pressure sensor.

Judge as NG if out of specification.

Scheme 11

1. Abnormality Judgment

If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.

JUDGMENT VALUE

Time Needed for Diagnosis: 2000 ms

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

1. Normality Judgment

Judge as OK and clear the NG if the continuous time while the following conditions are established is more than the predetermined time.

JUDGMENT VALUE

Time Needed for Diagnosis: Less than 1 second

Detect the open or short circuit of intake manifold pressure sensor.

Judge as NG if out of specification.

Scheme 12

1. Abnormality Judgment

If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.

JUDGMENT VALUE

Time Needed for Diagnosis: 2000 ms

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

1. Normality Judgment

Judge as OK and clear the NG if the continuous time while the following conditions are established is more than the predetermined time.

JUDGMENT VALUE

Time Needed for Diagnosis: Less than 1 second

Detect the malfunction of intake air temperature sensor output property.

Judge as NG when the intake air temperature is not varied whereas it seemed to be varied from the viewpoint of engine condition.

Scheme 13

1. Abnormality Judgment

Judge as NG when the following conditions are established.

JUDGMENT VALUE

Time Needed for Diagnosis: Less than 1 second

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

1. Normality Judgment

Judge as OK and clear the NG if the following conditions are established.

JUDGMENT VALUE

Time Needed for Diagnosis: Less than 1 second

Detect open or short circuit of the intake air temperature sensor.

Judge as NG if out of specification.

Scheme 14

1. Abnormality Judgment

If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.

JUDGMENT VALUE

Time Needed for Diagnosis: 500 ms

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

1. Normality Judgment

Judge as OK and clear the NG if the continuous time while the following conditions are established is more than the predetermined time.

JUDGMENT VALUE

Time Needed for Diagnosis: Less than 1 second

Detect open or short circuit of the intake air temperature sensor.

Judge as NG if out of specification.

Scheme 15

1. Abnormality Judgment

If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.

JUDGMENT VALUE

Time Needed for Diagnosis: 500 ms

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

1. Normality Judgment

Judge as OK and clear the NG if the continuous time while the following conditions are established is more than the predetermined time.

JUDGMENT VALUE

Time Needed for Diagnosis: Less than 1 second

Detect the malfunction of the engine coolant temperature sensor characteristics.

When the ignition is ON after the specified period of soaking time has elapsed, compare the engine coolant temperature with intake air temperature. Judge as NG if the difference between two temperatures is larger than the predetermined value and the engine coolant temperature becomes the specified value or more.

Scheme 16

1. Abnormality Judgment

If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.

JUDGMENT VALUE

Time Needed for Diagnosis: 512 ms

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

1. Normality Judgment

Judge as OK and clear the NG if the continuous time while the following conditions are established is more than the predetermined time.

JUDGMENT VALUE

Time Needed for Diagnosis: Less than 1 second

Detect the open or short circuit of the engine coolant temperature sensor.

Judge as NG if out of specification.

Scheme 17

1. Abnormality Judgment

If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.

JUDGMENT VALUE

Time Needed for Diagnosis: 500 ms

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

1. Normality Judgment

Judge as OK and clear the NG if the continuous time while the following conditions are established is more than the predetermined time.

JUDGMENT VALUE

Time Needed for Diagnosis: Less than 1 second

Detect the open or short circuit of the engine coolant temperature sensor.

Judge as NG if out of specification.

Scheme 18

1. Abnormality Judgment

If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.

JUDGMENT VALUE

Time Needed for Diagnosis: 500 ms

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

1. Normality Judgment

Judge as OK and clear the NG if the continuous time while the following conditions are established is more than the predetermined time.

JUDGMENT VALUE

Time Needed for Diagnosis: Less than 1 second

Detect the open or short circuit of throttle position sensor 1.

Judge as NG if out of specification.

Scheme 19

1. Abnormality Judgment

If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.

JUDGMENT VALUE

Time Needed for Diagnosis: 24 ms

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

1. Normality Judgment

Judge as OK and clear the NG if the continuous time while the following conditions are established is more than the predetermined time.

JUDGMENT VALUE

Time Needed for Diagnosis: 24 ms

Detect the open or short circuit of throttle position sensor 1.

Judge as NG if out of specification.

Scheme 20

1. Abnormality Judgment

If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.

JUDGMENT VALUE

Time Needed for Diagnosis: 24 ms

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

1. Normality Judgment

Judge as OK and clear the NG if the continuous time while the following conditions are established is more than the predetermined time.

JUDGMENT VALUE

Time Needed for Diagnosis: 24 ms

Detect the malfunction of engine coolant temperature output property.

Judge as NG when the engine coolant temperature does not rise in driving conditions where it should.

Scheme 21

1. Abnormality Judgment

Judge as NG if the criteria below are met.

JUDGMENT VALUE

Timer for diagnosis after engine start

1. Timer stop at fuel cut
2. During the driving conditions except a) above, timer counts up as follows.

64 ms + TWCNT ms (when at 64 ms)

TWCNT is defined as follows

TWCNT = 0 at idle switch ON

TWCNT show on the following table at idle switch OFF.

Judgment value of timer after engine starting

t = 359969 ms - 19601 ms x Ti

Ti : The lowest coolant temperature after engine start

Time Needed for Diagnosis: Less than 1 second

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

1. Normality Judgment

Judge as OK and clear the NG when the malfunction criteria below are met.

JUDGMENT VALUE

Time Needed for Diagnosis: Less than 1 second

Detect malfunctions of the thermostat function.

Judge as NG when any one of the following conditions is established.

1. When the actual engine coolant temperature does not reach the maximum temperature necessary to perform other OBDII diagnosis and Sum (Estimated engine coolant temperature - actual engine coolant temperature) exceeded the predetermined value. (Judgment 1)
2. When the actual engine coolant temperature does not reach the range within -11°C (-19.8°F) from the regulated temperature and Sum (Estimated engine coolant temperature - actual engine coolant temperature) exceeded the predetermined value. (Judgment 2)
3. When the difference between the estimated coolant temperature and the actual engine coolant temperature exceeds the predetermined value, and Sum (Estimated engine coolant temperature - actual engine coolant temperature) exceeded the predetermined value. (Judgment 3)

Scheme 22

1. Abnormality Judgment

If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.

JUDGMENT VALUE

MAP 4

MAP 5

MAP 6

MAP 7

MAP 8

MAP 9

Time Needed for Diagnosis: 300 - 700 seconds

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

1. Normality Judgment

Judge as OK and clear the NG if the continuous time while the following conditions are established is more than the predetermined time.

JUDGMENT VALUE

MAP 10

Time Needed for Diagnosis: 300 - 700 seconds

Detect the open or short circuit of sensor.

Judge as NG, when the element voltage is out of the specified range.

Scheme 23

1. Abnormality Judgment

If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.

JUDGMENT VALUE

Time Needed for Diagnosis

Input voltage (+): 1000 ms

Input voltage (-): 1000 ms

Input voltage (+) - Input voltage (-)|: 1000 ms

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

1. Normality Judgment

Judge as OK and clear the NG if the continuous time while the following conditions are established is more than the predetermined time.

JUDGMENT VALUE

Time Needed for Diagnosis: Less than 1 second

Detect the open or short circuit of sensor.

Judge as NG, when the element voltage is out of the specified range.

Scheme 24

1. Abnormality Judgment

If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.

JUDGMENT VALUE

Time Needed for Diagnosis

Input voltage (+): 1000 ms

Input voltage (-): 1000 ms

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

1. Normality Judgment

Judge as OK and clear the NG if the continuous time while the following conditions are established is more than the predetermined time.

JUDGMENT VALUE

Time Needed for Diagnosis: Less than 1 second

Detect open circuits of the sensor.

Judge as NG when the impedance of the element is large.

Scheme 25

1. Abnormality Judgment

If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.

JUDGMENT VALUE

Time Needed for Diagnosis: 5000 ms

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

1. Normality Judgment

Judge as OK and clear the NG if the continuous time while the following conditions are established is more than the predetermined time.

JUDGMENT VALUE

Time Needed for Diagnosis: Less than 1 second

Detect continuity NG of the oxygen sensor. If the oxygen sensor voltage reading is not within the probable range considering the operating conditions, judge as NG.

Scheme 26

1. Abnormality Judgment

If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.

JUDGMENT VALUE

Time Needed for Diagnosis

High: 2500 ms

Low (1): 20000 ms

Low (2): 40000 ms

Low (3): Value from Map

MAP

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

1. Normality Judgment

Judge as OK and clear the NG if the continuous time while the following conditions are established is more than the predetermined time.

JUDGMENT VALUE

Time Needed for Diagnosis

High: Less than 1 second

Low (1): Less than 1 second

Low (2): Less than 1 second

Low (3): Less than 1 second

Note. For the detection standard, refer to DTC P0137 O2 SENSOR CIRCUIT LOW VOLTAGE (BANK 1 SENSOR 2) .

Detect the slow response of rich --> lean for rear oxygen sensor output.

When the deceleration fuel cut has occurred, detect the trouble by calculating the time when the rear oxygen sensor output passes through the predetermined range of voltages.

Judge as NG when the response time is larger than the threshold value.

Scheme 27

Detect the trouble by calculating the response time of the rear oxygen sensor during fuel cut.

Scheme 28

1. Abnormality Judgment

Judge as NG when the following conditions are established.

JUDGMENT VALUE

Time Needed for Diagnosis: 10 seconds

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

1. Normality Judgment

Judge as OK and clear the NG if the following conditions are established.

JUDGMENT VALUE

Time Needed for Diagnosis: 10 seconds

Detect the slow response of lean --> rich for rear oxygen sensor output.

After the deceleration fuel cut has occurred, detect the trouble by calculating the time when the rear oxygen sensor output passes through the predetermined range of voltages.

Judge as NG when the response time is larger than the threshold value.

Scheme 29

Detect the trouble by calculating the response time of the rear oxygen sensor after fuel cut.

Scheme 30

1. Abnormality Judgment

Judge as NG when the following conditions are established.

JUDGMENT VALUE

Time Needed for Diagnosis: 10 seconds

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

1. Normality Judgment

Judge as OK and clear the NG if the following conditions are established.

JUDGMENT VALUE

Time Needed for Diagnosis: 10 seconds

Detect the delayed response of rear oxygen sensor output for rich --> lean.

After the deceleration fuel cut has started, detect the trouble by calculating the time when the rear oxygen sensor output decreases to the predetermined voltages.

Judge as NG when the response time is larger than the threshold value.

Scheme 31

Detect the trouble by calculating the time from the beginning of the fuel cut to the beginning of the rear oxygen sensor voltage starting to drop.

Scheme 32

1. Abnormality Judgment

Judge as NG when the following conditions are established.

JUDGMENT VALUE

Time Needed for Diagnosis: 10 seconds

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

1. Normality Judgment

Judge as OK and clear the NG if the following conditions are established.

JUDGMENT VALUE

Time Needed for Diagnosis: 10 seconds

Detect the delayed response of rear oxygen sensor output for lean --> rich.

After the deceleration fuel cut has completed, detect the trouble by calculating the time when the rear oxygen sensor output increases to the predetermined voltages.

Judge as NG when the response time is larger than the threshold value.

Scheme 33

Detect the trouble by calculating the time from the completion of the fuel cut to the beginning of the rear oxygen sensor voltage starting to rise.

Scheme 34

1. Abnormality Judgment

Judge as NG when the following conditions are established.

JUDGMENT VALUE

Time Needed for Diagnosis: 10 seconds

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

1. Normality Judgment

Judge as OK and clear the NG if the following conditions are established.

JUDGMENT VALUE

Time Needed for Diagnosis: 10 seconds

Detect the rear oxygen sensor open or short circuit. Judge as NG when the rear oxygen sensor voltage can be determined to be abnormal considering conditions such as intake air amount, engine coolant temperature, main feedback control and deceleration fuel cut.

Scheme 35

1. Abnormality Judgment

If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.

JUDGMENT VALUE

Time Needed for Diagnosis: 200000 ms

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

1. Normality Judgment

Judge as OK and clear the NG if the following conditions are established.

JUDGMENT VALUE

Detect the malfunction of rear oxygen sensor heater.

While observing the engine condition, judge as NG if the rear oxygen sensor impedance is great.

Scheme 36

1. Abnormality Judgment

If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.

JUDGMENT VALUE

Time Needed for Diagnosis: 4 ms x 2500 time(s)

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

1. Normality Judgment

Judge as OK and clear the NG if the continuous time while the following conditions are established is more than the predetermined time.

JUDGMENT VALUE

Time Needed for Diagnosis: 4 ms x 2500 time(s)

Detect the slow response of front oxygen (A/F) sensor.

For diagnosis, detect the trouble by processing the lambda waveform in normal driving without forcibly changing the target air fuel ratio.

Scheme 37