Subaru 2002 IMPREZA Service Manual page 1499

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
Step
1 CHECK HARNESS BETWEEN ECM AND
TCM CONNECTOR.
1)Turn the ignition switch to ON.
2)Measure the voltage between ECM and
chassis ground.
Connector & terminal
(B135) No. 20 (+) — Chassis ground ( − − − − ):
2 CHECK HARNESS BETWEEN ECM AND
TCM CONNECTOR.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B135) No. 20 (+) — Chassis ground ( − − − − ):
3 CHECK HARNESS BETWEEN ECM AND
TCM CONNECTOR.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B135) No. 20 (+) — Chassis ground ( − − − − ):
4 CHECK OUTPUT SIGNAL FROM ECM.
Measure the voltage between ECM and chas-
sis ground.
Connector & terminal
(B135) No. 20 (+) — Chassis ground ( − − − − ):
5 CHECK HARNESS BETWEEN ECM AND
TCM CONNECTOR.
Measure the voltage between TCM and chas-
sis ground.
Connector & terminal
(B54) No. 20 (+) — Chassis ground ( − − − − ):
6 CHECK POOR CONTACT.
Check poor contact in TCM connector.
Check
Is the voltage more than 10 V? Repair the battery
Is the voltage more than 4 V?
Is the voltage less than 1 V?
Does the voltage change from
1 V to 4 V while monitoring the
value with voltage meter?
Is the voltage more than 4 V?
Is there poor contact in TCM
connector?
EN(TURBO)-339
ENGINE (DIAGNOSTICS)
Yes
Go to step 2.
short circuit in har-
ness between
ECM and TCM
connector. After
repair, replace the
ECM. <Ref. to
FU(TURBO)-49,
Engine Control
Module.>
Go to step 5. Go to step 3.
Repair the poor Go to step 4.
contact in ECM
connector.
Even if MIL lights Contact with your
up, the circuit has Subaru distributor
returned to a nor- service.
mal condition at
NOTE:
this time.
Inspection by DTM
is required,
NOTE:
In this case, repair cause
the following: cause is deteriora-
• Poor contact in tion of
ECM connector parts.
• Poor contact in
TCM connector
Go to step 6. Repair the open
circuit in harness
between ECM and
TCM connector.
Repair the poor Check the TCM
contact in TCM power supply line
connector. and grounding
line.
No
be-
probable
multiple