Subaru 2002 IMPREZA Service Manual page 711

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. 4 (+) — Chassis ground ( − − − − ):
2 CHECK HARNESS BETWEEN ECM AND
TCM CONNECTOR.
1)Turn the ignition switch to OFF.
2)Disconnect the connector from ECM and
TCM.
3)Measure the resistance of harness between
ECM and chassis ground.
Connector & terminal
(B135) No. 4 — Chassis ground:
3 CHECK OUTPUT SIGNAL FOR ECM.
1)Connect the connector to ECM.
2)Turn the ignition switch to ON.
3)Measure the voltage between ECM and
chassis ground.
Connector & terminal
(B135) No. 4 (+) — Chassis ground ( − − − − ):
4 CHECK TROUBLE CODE FOR AUTOMATIC
TRANSMISSION.
Read the DTC for automatic transmission.
<Ref. to AT-22, Read Diagnostic Trouble Code
(DTC).>
Check
Is the voltage less than 1 V?
Is the resistance less than 10
Ω?
Is the voltage more than 5 V?
Does the DTC appear for auto-
matic transmission?
EN-279
ENGINE (DIAGNOSTICS)
Yes
Go to step 2. Even if MIL lights
up, the circuit has
returned to a nor-
mal condition at
this time.
NOTE:
In this case, repair
the following:
• Poor contact in
ECM connector
• Poor contact in
TCM connector
Repair the ground Go to step 3.
short circuit in har-
ness between
ECM and TCM
connector.
Go to step 4. Repair the poor
contact in ECM
connector.
Inspect the DTC Replace the TCM.
for automatic <Ref. to AT-46,
transmission. Transmission Con-
<Ref. to AT-42, trol Module
Diagnostic Proce- (TCM).>
dure with Diagnos-
tic Trouble Code
(DTC).>
No