Subaru Legacy 2005 Service Manual page 1817

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step
1 CHECK OUTPUT SIGNAL FROM ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B136) No. 16 (+) — Chassis ground (
2 CHECK OUTPUT SIGNAL FROM ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B136) No. 16 (+) — Chassis ground (
3 CHECK INPUT SIGNAL OF ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B136) No. 22 (+) — Chassis ground (
4 CHECK INPUT SIGNAL OF ECM (USING
SUBARU SELECT MONITOR).
Read the data of atmospheric absolute pres-
sure signal using Subaru Select Monitor.
NOTE:
For detailed operation procedure, refer to
"READ CURRENT DATA FOR ENGINE". <Ref.
to EN(H6DO)(diag)-26, Subaru Select Moni-
tor.>
5 CHECK HARNESS BETWEEN ECM AND
MANIFOLD ABSOLUTE PRESSURE SEN-
SOR CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from manifold
absolute pressure sensor.
3) Turn the ignition switch to ON.
4) Measure the voltage between manifold
absolute pressure sensor connector and
engine ground.
Connector & terminal
(E28) No. 3 (+) — Engine ground (
6 CHECK HARNESS BETWEEN ECM AND
MANIFOLD ABSOLUTE PRESSURE SEN-
SOR CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Measure the resistance of harness
between ECM and manifold absolute pressure
sensor connector.
Connector & terminal
(B136) No. 22 — (E28) No. 2:
7 CHECK HARNESS BETWEEN MANIFOLD
ABSOLUTE PRESSURE SENSOR CONNEC-
TOR.
1) Turn the ignition switch to ON.
2) Measure the voltage between ECM con-
nector and chassis ground.
Connector & terminal
(B136) No. 22 (+) — Chassis ground (
Check
Is the voltage more than 4.5 V? Go to step 3.
−
):
Does the voltage change by
shaking the ECM harness and
connector?
−
):
Is the voltage more than 4.5 V? Go to step 5.
−
):
Is the value more than 13.3
kPa (100 mmHg, 3.94 inHg)
when shaking the ECM har-
ness and connector?
Is the voltage more than 4.5 V? Go to step 6.
−
):
Is the resistance less than 1
Ω?
Is the voltage more than 4.5 V? Repair the battery
−
):
EN(H6DO)(diag)-121
ENGINE (DIAGNOSTICS)
Yes
Go to step 2.
Repair the poor Replace the ECM.
contact in ECM <Ref. to
connector. FU(H6DO)-34,
Engine Control
Module (ECM).>
Go to step 4.
Repair the poor Go to step 5.
contact in ECM
connector.
Repair the open
circuit of harness
between ECM and
manifold absolute
pressure sensor
connector.
Go to step 7. Repair the open
circuit of harness
between ECM and
manifold absolute
pressure sensor
connector.
Go to step 8.
short of harness
between ECM and
manifold absolute
pressure sensor
connector.
No