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Home >> Subaru >> 2008 >> Forester XT, Standard >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Diagnostic Trouble Code (DTC) Detecting Criteria (H4DOTC) >> Diagnostic Trouble Code (DTC) Detecting Criteria >> DTC P1602 Control Module Programming Error >> Diagnostic Method
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Diagnostic Method

Abnormality Judgment 

When the diagnostic execution conditions are established, calculate the estimated exhaust temperature.

Judge as NG if the following conditions are established within 14 seconds after starting the engine.

Judgment Value 

JUDGMENT VALUE CHART

Malfunction Criteria Threshold Value
Estimated exhaust temperature < Value from Map 1

Map 1 

MAP 1 REFERENCE

Coolant temperature at engine start -40°C (-40°F) -30°C (-22°F) -20°C (-4°F) -10°C (14°F) 0°C (32°F) 10°C (50°F) 20°C (68°F) 30°C (86°F) 40°C (104°F) 50°C (122°F)
Threshold Value 200°C (392°F) 200°C (392°F) 200°C (392°F) 200°C (392°F) 200°C (392°F) 200°C (392°F) 180°C (356°F) 180°C (356°F) 180°C (356°F) 180°C (356°F)

Time Needed for Diagnosis:  14 seconds

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

Judge as OK when the following conditions are established after predetermined amount of time has passed.

Judgment Value 

JUDGMENT VALUE CHART

Malfunction Criteria Threshold Value
Estimated exhaust temperature ≥ Value from Map 1

Judge as NG when all the following conditions are established and judge as OK when not met.

JUDGMENT VALUE CHART

Malfunction Criteria Threshold Value
Continuous time of (target engine RPM - engine RPM > 100) ≥ 10000 milliseconds
Continuous time when (actual retard amount > 5°CA) ≥ 3000 milliseconds

Time Needed for Diagnosis:  6 seconds

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