Subaru Impreza 2003, Service Manual

Page: 1415 / 3610

EN(H4DOTC)-239
ENGINE (DIAGNOSTICS)
DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
BX:DTC P0734 — GEAR 4 INCORRECT RATIO —
• DTC DETECTING CONDITION:
• Two consecutive driving cycles with fault
• TROUBLE SYMPTOM:
• Shift point too high or too low; engine brake not effective in “3” range; excessive shift shock; excessive
tight corner “braking”
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode <Ref. to EN(H4DOTC)-48, OP-
ERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4DOTC)-40, Inspection Mode.>.
• WIRING DIAGRAM:
Step Check Yes No
1 CHECK ANY OTHER DTC ON DISPLAY. Is any other DTC displayed? Inspect the rele-
vant DTC using
“List of Diagnostic
Trouble Code
(DTC)”. <Ref. to
EN(H4DOTC)-75,
List of Diagnostic
Trouble Code
(DTC).> Go to step 2.
2 CHECK THROTTLE POSITION SENSOR
CIRCUIT.
Check the throttle position sensor circuit. <Ref.
to 4AT-48, DTC 31 THROTTLE POSITION
SENSOR, Diagnostic Procedure with Diagnos-
tic Trouble Code (DTC).>
Is there any trouble in throttle
position sensor circuit? Repair or replace
the throttle posi-
tion sensor circuit. Go to step 3.
3 CHECK FRONT VEHICLE SPEED SENSOR
CIRCUIT.
Check the front vehicle speed sensor circuit.
<Ref. to 4AT-53, DTC 33 FRONT VEHICLE
SPEED SENSOR, Diagnostic Procedure with
Diagnostic Trouble Code (DTC).>
Is there any trouble in front
vehicle speed sensor circuit? Repair or replace
the vehicle speed
sensor 2 circuit. Go to step 4.
4 CHECK TORQUE CONVERTER TURBINE
SPEED SENSOR CIRCUIT.
Check the torque converter turbine speed sen-
sor circuit. <Ref. to 4AT-57, DTC 36 TORQUE
CONVERTER TURBINE SPEED SENSOR,
Diagnostic Procedure with Diagnostic Trouble
Code (DTC).>
Is there any trouble in torque
converter turbine speed sensor
circuit? Repair or replace
the torque con-
verter turbine
speed sensor cir-
cuit. Go to step 5.
5 CHECK POOR CONTACT.
Check poor contact in TCM connector.
Is there poor contact in TCM
connector? Repair the poor
contact in TCM
connector. Go to step 6.
6 CHECK MECHANICAL TROUBLE.
Check mechanical trouble in automatic trans-
mission.
Is there any mechanical trou-
ble in automatic transmission? Repair or replace
the automatic
transmission.
<Ref. to 4AT-33,
INSPECTION,
Road Test.> Replace the TCM.
<Ref. to 4AT-70,
Transmission Con-
trol Module
(TCM).>