Subaru IMPREZA 2004 Service Manual page 521

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step
2 CHECK HARNESS BETWEEN TCM AND
BRAKE LIGHT SWITCH CONNECTOR.
1)Disconnect the connectors from TCM and
brake light switch.
2)Measure the resistance of harness between
TCM and brake light switch connector.
Connector & terminal
LHD
(B55) No. 12 — (B64) No. 1:
RHD
(B55) No. 12 — (B64) No. 2:
3 CHECK HARNESS BETWEEN TCM AND
BRAKE LIGHT SWITCH CONNECTOR.
Measure the resistance of harness between
TCM and chassis ground.
Connector & terminal
(B55) No. 12 — Chassis ground:
4 CHECK INPUT SIGNAL FOR TCM.
1)Connect the connectors to TCM and brake
light switch.
2)Measure the voltage between TCM and
chassis ground.
Connector & terminal
(B55) No. 12 (+) — Chassis ground ( − − − − ):
5 CHECK INPUT SIGNAL FOR TCM.
Measure the voltage between TCM and chas-
sis ground.
Connector & terminal
(B55) No. 12 (+) — Chassis ground ( − − − − ):
6 CHECK POOR CONTACT.
Check poor contact in TCM connector.
Check
Is the resistance less than 1
Ω?
Is the resistance more than 1
MΩ?
Is the voltage less than 1 V
when releasing the brake
pedal?
Is the voltage more than 10 V
when depressing the brake
pedal?
Is there poor contact in TCM
connector?
EN(H4SO)(diag)-212
Yes
Go to step 3. Repair or replace
the harness and
connector.
NOTE:
In this case, repair
the following:
• Open circuit in
harness between
TCM and brake
light switch con-
nector
• Poor contact in
TCM connector
• Poor contact in
brake light switch
connector
Go to step 4. Repair ground
short circuit in har-
ness between
TCM and brake
light switch con-
nector.
Go to step 5. Adjust or replace
the brake light
switch. <Ref. to LI-
8, STOP LIGHT
SWITCH,
INSPECTION,
Stop Light Sys-
tem.>
Go to step 6. Adjust or replace
the brake light
switch. <Ref. to LI-
8, STOP LIGHT
SWITCH,
INSPECTION,
Stop Light Sys-
tem.>
Repair poor con- Replace the TCM.
tact in TCM con- <Ref. to 4AT-74,
nector. Transmission Con-
trol Module
(TCM).>
No