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Home >> Subaru >> 2023 >> WRX Base, Standard Trans >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (Diagnostics) (3 Of 4) >> Diagnostic Procedure with Diagnostic Trouble Code (DTC) >> DTC P1261: Cylinder 1 Direct Fuel Injector Circuit/Open >> General Description >> Diagnostic Method

Diagnostic Method

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

Judgment value

JUDGMENT VALUE SPECIFICATION - DIAGNOSIS 1 (POWER SUPPLY SHORT)

Malfunction Criteria Threshold Value
Fuel injector supply voltage - Fuel injector terminal voltage (+) 2 V or less
JUDGMENT VALUE SPECIFICATION - DIAGNOSIS 2 (GROUND SHORT)

Malfunction Criteria Threshold Value
Fuel injector terminal voltage (-) - Ground 2 V or less
JUDGMENT VALUE SPECIFICATION - DIAGNOSIS 3 (OPEN CIRCUIT)

Malfunction Criteria Threshold Value
Condition 1 and condition 2 are continuously detected
Condition 1:
Fuel injector supply voltage - Fuel injector terminal voltage (+)
2 V or less
Condition 2:
Fuel injector terminal voltage (-) - Ground
2 V or less
JUDGMENT VALUE SPECIFICATION - DIAGNOSIS 4 (SHORT CIRCUIT, OVERCURRENT)

Malfunction Criteria Threshold Value
Fuel injector current 3.5 μs after the injection command 3 A or more

Time needed for diagnosis: 

Diagnosis 1, 2 and 3: 50 times

Diagnosis 4: 25 times

ENGINE SPEED SPECIFICATION - MAP

Engine speed (rpm) Time needed for 50 times of diagnosis (sec) Time needed for 25 times of diagnosis (sec)
500 3 1.5
2000 0.75 0.375
4000 0.375 0.1875
6000 0.25 0.125

Malfunction indicator light illumination:  Illuminates as soon as a malfunction occurs.