Subaru Legacy 2004 Service Manual page 853

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step
6 CHECK HARNESS BETWEEN ECM AND
MASS AIR FLOW SENSOR CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Measure the resistance of harness
between ECM and mass air flow sensor con-
nector.
Connector & terminal
(B136) No. 23 — (B3) No. 3:
(B136) No. 31 — (B3) No. 2:
(B136) No. 35 — (B3) No. 5:
7 CHECK HARNESS BETWEEN ECM AND
MASS AIR FLOW SENSOR CONNECTOR.
Measure the resistance of harness between
ECM and chassis ground.
Connector & terminal
(B136) No. 23 — Chassis ground:
(B136) No. 31 — Chassis ground:
(B136) No. 35 — Chassis ground:
8 CHECK POOR CONTACT.
Check poor contact in mass air flow sensor
connector.
Check
Is the resistance less than 1
!?
Is the resistance more than 1
M!?
Is there poor contact in mass
air flow sensor connector?
EN(H4SO 2.5)(diag)-94
Yes
Go to step 7. Repair the open
circuit between
ECM and mass air
flow sensor con-
nector.
Go to step 8. Repair the ground
short circuit
between ECM and
mass air flow sen-
sor connector.
Repair the poor Replace the mass
contact in mass air air flow and intake
flow sensor con- air temperature
nector. sensor. <Ref. to
FU(H4SO 2.5)-26,
Mass Air Flow and
Intake Air Temper-
ature Sensor.>
No