DIAGNOSTIC METHOD 2 Subaru Forester SJ

DIAGNOSTIC METHOD 2

Detect the malfunction by the cumulative value obtained from the amount of variation in lambda change.

Scheme 165

1. Abnormality Judgment

Judge as NG when the following conditions are established.

JUDGMENT VALUE

MAP SPECIFICATION

Time Needed for Diagnosis: 120 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: 120 seconds

Note. For the detection standard, refer to DTC P014C. < Ref. to DTC P014C O2 SENSOR SLOW RESPONSE - RICH TO LEAN (BANK 1 SENSOR 1) , Diagnostic Trouble Code (DTC) Detecting Criteria. >

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 166

Detect the malfunction depending on the average value of time necessary for lambda to inverse the air fuel ratio from "Lean --> Rich --> Lean" to "Rich --> Lean --> Rich".

Scheme 167

1. Abnormality Judgment

Judge as NG when the following conditions are established.

JUDGMENT VALUE

Time Needed for Diagnosis: 100 times of inversion

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: 100 times of inversion

Detect the malfunction by calculating the average amplitude of lambda.

Scheme 168

1. Abnormality Judgment

Judge as NG when the following conditions are established.

JUDGMENT VALUE

Time Needed for Diagnosis: 90 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: 90 seconds

Note. For the detection standard, refer to DTC P015A. < Ref. to DTC P015A O2 SENSOR DELAYED RESPONSE - RICH TO LEAN (BANK 1 SENSOR 1) , Diagnostic Trouble Code (DTC) Detecting Criteria. >

Detect fuel system malfunction by the amount of main feedback control.

Fuel system is diagnosed by comparing the target air fuel ratio calculated by ECM with the actual air fuel ratio measured by sensor.

1. Abnormality Judgment

Compare the diagnostic value with the threshold value, and if a condition meeting the criteria continues for 10 s x 3 times or more, judge that there is a fault in the fuel system.

JUDGMENT VALUE

Time Needed for Diagnosis: 10 s x 3 times

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: 10 seconds

Detect fuel system malfunction by the amount of main feedback control.

Fuel system is diagnosed by comparing the target air fuel ratio calculated by ECM with the actual air fuel ratio measured by sensor.

1. Abnormality Judgment

Compare the diagnostic value with the threshold value, and if a condition meeting the criteria continues for 10 s x 3 times or more, judge that there is a fault in the fuel system.

JUDGMENT VALUE

Time Needed for Diagnosis: 10 s x 3 times

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

1. Normality Judgment

Judge as OK if the status that the criteria below are met continues for 10 seconds.

JUDGMENT VALUE

Time Needed for Diagnosis: 10 seconds

Detect the signal stuck of the fuel pressure sensor.

Judge as NG when the voltage change amount per unit time of the fuel pressure sensor does not exceed the threshold value.

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: 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 continuous time while the following conditions are established is more than the predetermined time.

JUDGMENT VALUE

Time Needed for Diagnosis: 5 seconds

Detect the open or short circuit of the fuel pressure sensor.

Judge as NG if out of specification.

Scheme 169

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: 2500 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 fuel pressure sensor.

Judge as NG if out of specification.

Scheme 170

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: 2500 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 for abnormal values in the oil temperature sensor output properties.

Judge as NG when the oil temperature does not rise even though the engine is running under a condition where it should rise.

Scheme 171

1. Abnormality Judgment

Judge as NG when the following conditions are established.

JUDGMENT VALUE

After engine start oil temperature sensor characteristic diagnosis timer (timer for diagnosis)

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

64 ms + TOILCNT ms (when at 64 ms)

Where, TOILCNT is determined as follows

TOILCNT = 0 at idle switch ON

For TOILCNT at Idle switch off, refer to the following table.

After engine start oil temperature characteristic diagnosis timer judgment value (t)

t = 1829497 - 46830 x Ti (t > or = 284107)

Ti = The lowest coolant temperature after starting the engine

Time Needed for Diagnosis: 250 - 550 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: Less than 1 second

Detect the open or short circuit of the oil temperature sensor.

Judge as NG when outside of the judgment value.

Scheme 172

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: 520 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 oil temperature sensor.

Judge as NG when outside of the judgment value.

Scheme 173

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: 520 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 2.

Judge as NG if out of specification.

Scheme 174

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: 100 ms

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

1. Normality Judgment

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: Less than 1 second

Detect the open or short circuit of throttle position sensor 2.

Judge as NG if out of specification.

Scheme 175

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: 100 ms

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

1. Normality Judgment

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: Less than 1 second

Detect the malfunction of fuel pump control unit.

Judge as NG when the NG signal is sent through a diagnostic line coming from the fuel pump control unit.

Fuel pump control unit detects the open or short circuit malfunction for each line, and then sends NG signals if one of them is found NG.

Scheme 176

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: 2520 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 malfunction of high pressure fuel pump circuit function.

Judge as NG when ECM detects any malfunction in the diagnostic items listed below.

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: TDC x 75 times

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: TDC x 75 times

Detect the malfunction of wastegate control solenoid valve function.

Judge as NG when becoming high wastegate pressure.

Scheme 177

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 SPECIFICATION

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 open or short circuit of the wastegate control solenoid valve.

Judge as NG when the terminal output voltage remains Low during outputting the duty signal.

Scheme 178

Detect open or short circuit of the wastegate control solenoid valve.

Judge as NG when the terminal output voltage remains Low or High during outputting the duty signal.

Scheme 179

Note. For the detection standard, refer to DTC P0301. < Ref. to DTC P0301 CYLINDER 1 MISFIRE DETECTED , Diagnostic Trouble Code (DTC) Detecting Criteria. >

Detect the presence of misfire occurrence. (Revolution fluctuation method)

Monitoring Misfire which influences exhaust deterioration (1.5 times of FTP) and catalyst damage is made obligatory by the law. Misfire affecting these two has two patterns below

1. Intermittent misfire (The same cylinder misfires in random, or different cylinders misfire in random.): FTP 1.5 times misfire
2. 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.

1. Intermittent misfire: FTP 1.5 times misfire 180° Interval Difference Method 360° Interval Difference Method (whole range) 720° Interval Difference Method (3, 000 rpm or more)
2. Misfire every time: FTP 1.5 times misfire, Catalyst damage misfire 360° Interval Difference Method

When a misfire occurs, the engine speed will decrease 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 a misfire is occurring or not comparing the calculated result with judgment value. Count the number of misfires, if the misfire ratio is higher during 1000 revs. or 200 revs., judge corresponding cylinders as NG.

As shown in the following figure, pick a 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, etc.

Scheme 180

Note. For the detection standard, refer to DTC P0301. < Ref. to DTC P0301 CYLINDER 1 MISFIRE DETECTED , Diagnostic Trouble Code (DTC) Detecting Criteria. >

Note. For the detection standard, refer to DTC P0301. < Ref. to DTC P0301 CYLINDER 1 MISFIRE DETECTED , Diagnostic Trouble Code (DTC) Detecting Criteria. >

Note. For the detection standard, refer to DTC P0301. < Ref. to DTC P0301 CYLINDER 1 MISFIRE DETECTED , Diagnostic Trouble Code (DTC) Detecting Criteria. >

Detect the open or short circuit of knock sensor.

Judge as NG if out of specification.

Scheme 181

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: 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 knock sensor.

Judge as NG if out of specification.

Scheme 182

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: 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 knock sensor.

Judge as NG if out of specification.

Scheme 183

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: 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 knock sensor.

Judge as NG if out of specification.

Scheme 184

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: 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 the crankshaft position sensor.

Judge as NG when the crank signal is not input even though the starter was rotated.

Scheme 185

Scheme 186

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: 3000 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 for faults in crankshaft position sensor output properties.

Judge as NG when there is a problem in the number of crankshaft signals for every revolution of crankshaft.

Scheme 187

Scheme 188

1. Abnormality Judgment

Judge as NG when the following conditions are established.

Diagnosis 1

JUDGMENT VALUE

Diagnosis 2

JUDGMENT VALUE

Time Needed for Diagnosis: 10 engine revs.

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.

Diagnosis 1

JUDGMENT VALUE

Diagnosis 2

JUDGMENT VALUE

Time Needed for Diagnosis: 10 engine revs.

Detect the open or short circuit of the camshaft position sensor.

When there is no camshaft position signal input continuously, judge as NG.

Scheme 189

1. Abnormality Judgment

Diagnosis 1

Judge as NG when no input of camshaft position sensor signal in TDC remains for 14 times.

JUDGMENT VALUE

Time Needed for Diagnosis: TDC x 10 times

Diagnosis 2

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: 3000 ms

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

1. Normality Judgment

Diagnosis 1

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

JUDGMENT VALUE

Time Needed for Diagnosis: TDC x 10 times

Diagnosis 2

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 camshaft position sensor property.

Judge as NG when the number of camshaft signals remains abnormal.

Scheme 190

1. Abnormality Judgment

Judge as NG when the condition where the number of camshaft position sensor signals are less than 3 times during 2 revs of crankshaft.

JUDGMENT VALUE

Time Needed for Diagnosis: Engine two revolutions x 4 times

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

1. Normality Judgment

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

JUDGMENT VALUE

Time Needed for Diagnosis: Engine two revolutions x 4 times

Note. For the detection standard, refer to DTC P0340. < Ref. to DTC P0340 CAMSHAFT POSITION SENSOR "A" CIRCUIT (BANK 1 OR SINGLE SENSOR) , Diagnostic Trouble Code (DTC) Detecting Criteria. >

Note. For the detection standard, refer to DTC P0341. < Ref. to DTC P0341 CAMSHAFT POSITION SENSOR "A" CIRCUIT RANGE/PERFORMANCE (BANK 1 OR SINGLE SENSOR) , Diagnostic Trouble Code (DTC) Detecting Criteria. >

Based on the self-diagnostic result of the ignition coil driving IC, judge the ignition coil driving circuit as normal or abnormal.

The ignition coil driving IC detects "no ignition" status as a malfunction.

1. Abnormality Judgment

Judge as NG when the following conditions are established.

JUDGMENT VALUE

Time Needed for Diagnosis: 2500 ms

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

1. Normality Judgment

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

JUDGMENT VALUE

Time Needed for Diagnosis: 500 ms

Note. For the detection standard, refer to DTC P0351. < Ref. to DTC P0351 IGNITION COIL A PRIMARY/SECONDARY CIRCUIT , Diagnostic Trouble Code (DTC) Detecting Criteria. >

Note. For the detection standard, refer to DTC P0351. < Ref. to DTC P0351 IGNITION COIL A PRIMARY/SECONDARY CIRCUIT , Diagnostic Trouble Code (DTC) Detecting Criteria. >

Note. For the detection standard, refer to DTC P0351. < Ref. to DTC P0351 IGNITION COIL A PRIMARY/SECONDARY CIRCUIT , Diagnostic Trouble Code (DTC) Detecting Criteria. >

Detect the open or short circuit of the camshaft position sensor.

When there is no camshaft position signal input continuously, judge as NG.

Scheme 191

1. Abnormality Judgment

Judge as NG when no input of camshaft position sensor signal in TDC remains for 15 times.

JUDGMENT VALUE

Time Needed for Diagnosis: TDC x 15 times

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

1. Normality Judgment

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

JUDGMENT VALUE

Time Needed for Diagnosis: TDC x 15 times

Detect the malfunction of camshaft position sensor property.

Judge as NG when the number of camshaft signals remains abnormal.

Scheme 192

1. Abnormality Judgment

Judge as NG when the condition where the number of camshaft position sensor signals are less than 2 times during 2 revs of crankshaft.

JUDGMENT VALUE

Time Needed for Diagnosis: Engine two revolutions x 4 times

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

1. Normality Judgment

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

JUDGMENT VALUE

Time Needed for Diagnosis: Engine two revolutions x 4 times

Note. For the detection standard, refer to DTC P0365. < Ref. to DTC P0365 CAMSHAFT POSITION SENSOR "B" CIRCUIT (BANK 1) , Diagnostic Trouble Code (DTC) Detecting Criteria. >

Note. For the detection standard, refer to DTC P0390. < Ref. to DTC P0390 CAMSHAFT POSITION SENSOR "B" CIRCUIT (BANK 2) , Diagnostic Trouble Code (DTC) Detecting Criteria. >

For the detection standard, refer to DTC P0366. < Ref. to DTC P0366 CAMSHAFT POSITION SENSOR B CIRCUIT RANGE/PERFORMANCE (BANK 1) , Diagnostic Trouble Code (DTC) Detecting Criteria. >

Detect EGR system malfunction.

Intake manifold pressure (negative pressure) is constant because the throttle valve is fully closed during deceleration fuel cut. At this time, when the EGR valve is opened/closed, the intake manifold pressure will change. EGR System OK/NG is judged by the range of this change.

Scheme 193

Measure the pressure values when the enable conditions are established, and perform diagnosis by calculating those results.

1. Label the intake manifold pressure value as PMOF1, which is observed when enable conditions are established, and set the EGR target step to 55 steps (nearly full open).
2. Label the intake manifold pressure value as PMON, which is observed after one second has passed since EGR target step was set to 55 steps (when the enable conditions were established), and set the EGR target step to 0.
3. Label the intake manifold pressure as PMOF2, which is observed after one second has passed since EGR target step was set to 0 (after two seconds have passed since the enable conditions were established).

1. Abnormality Judgment

Judge as NG when the following conditions are established.

JUDGMENT VALUE

Time Needed for Diagnosis: 2 seconds

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

Scheme 194

1. Normality Judgment

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

JUDGMENT VALUE

Time Needed for Diagnosis: 2 seconds

Detect the deterioration of the catalyst function.

Though the front oxygen sensor output would change slowly with a new catalyst, the sensor output with a deteriorated catalyst becomes high and the inversion time is shortened.

For this reason, the catalyst diagnosis is carried out by monitoring the front oxygen sensor output and comparing it with the front oxygen (A/F) sensor output.

Scheme 195

After the enable conditions have been established, calculate the front oxygen (A/F) sensor lambda value deviation sum value (Sum (sglmd n - sglmd n-1 )), and rear oxygen sensor output voltage deviation sum value (Sum (ro2sad n - ro2sad n-1 )) in every 32 ms x 4 times. If the front oxygen (A/F) sensor lambda value deviation sum value (Sum (sglmd n - sglmd n - 1 )) is the predetermined value or more, calculate the diagnostic value.

1. Abnormality Judgment

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

JUDGMENT VALUE

Time Needed for Diagnosis: 30 - 55 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 within the predetermined time.

JUDGMENT VALUE

Time Needed for Diagnosis: 30 - 55 seconds

Detect the malfunction of purge flow by the change of ELCM pressure sensor output value before/after purge introduction.