Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Manual - part 288

EN(H4DOTC)(diag)-376

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL MO-
TOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Measure the resistance between electronic
throttle control connector and engine ground.

Connector & terminal

(E57) No. 2 — Engine ground:
(E57) No. 1 — Engine ground:

Is the resistance 1 MΩ or
more?

Go to step

17.

Repair the ground
short circuit of har-
ness between
ECM connector
and electronic
throttle control
connector.

CHECK ELECTRONIC THROTTLE CON-
TROL MOTOR HARNESS.
Measure the resistance between electronic
throttle control connectors.

Connector & terminal

(E57) No. 2 — (E57) No. 1:

Is the resistance 1 MΩ or
more?

Go to step

18.

Repair the short
circuit in harness
between ECM con-
nector and elec-
tronic throttle
control connector.

CHECK ELECTRONIC THROTTLE CON-
TROL GROUND CIRCUIT.
Measure the resistance between ECM connec-
tor and chassis ground.

Connector & terminal

(B134) No. 3 — Chassis ground:
(B134) No. 4 — Chassis ground:
(B134) No. 6 — Chassis ground:
(B137) No. 1 — Chassis ground:
(B137) No. 3 — Chassis ground:

Is the resistance less than 5 Ω? Go to step

19.

Repair the harness
and connector.
NOTE:

In this case, repair
the following item:
• Open circuit of
harness between
ECM

connector

and engine ground
• Poor contact of
coupling connector

CHECK ELECTRONIC THROTTLE CON-
TROL.
Measure the resistance between electronic
throttle control terminals.

Terminals

No. 2 — No. 1:

Is the resistance 50 Ω or less? Go to step

20.

Replace the elec-
tronic throttle con-
trol. <Ref. to
FU(STI)-15, Throt-
tle Body.> <Ref. to
FU(w/o STI)-15,
Throttle Body.>

CHECK ELECTRONIC THROTTLE CON-
TROL.
Move the throttle valve to the fully open and fully
closed positions with fingers.
Check that the valve returns to the specified
position when releasing fingers.

Does the valve return to the
specified position? Standard
value: 3 mm (0.12 in) from fully
closed position

Repair the poor
contact of ECM
connector.

Replace the elec-
tronic throttle con-
trol. <Ref. to
FU(STI)-15, Throt-
tle Body.> <Ref. to
FU(w/o STI)-15,
Throttle Body.>

Step

Check

Yes

EN(H4DOTC)(diag)-377

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

EN:DTC P2102 THROTTLE ACTUATOR CONTROL MOTOR CIRCUIT LOW

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(H4DOTC)-245, DTC P2102 THROTTLE ACTUATOR CONTROL

MOTOR CIRCUIT LOW, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Improper idling

• Poor driving performance

• Engine stalls.
CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(H4DOTC)(diag)-63,

OPERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(H4DOTC)(diag)-49, PROCE-

DURE, Inspection Mode.>.

WIRING DIAGRAM:

• Engine electrical system, without SI-DRIVE <Ref. to WI-32, WITHOUT SI-DRIVE, WIRING DIAGRAM,

Engine Electrical System.>

• Engine electrical system, with SI-DRIVE <Ref. to WI-48, WITH SI-DRIVE, WIRING DIAGRAM, Engine

Electrical System.>

ECM

EN-08727

22 23

11 12 13 14 15

26 27

16 17

18 19 20 21

33 34

30 31

B136

B134

B17

A29

B21

B122

A19

E57

B134

B220

B137

B136

B135

15A

B220

B135

B220

3
5

36 39

28 31

B122

B21

D: B137

E57

SBF-7

FUSE

(RELAY BLOCK)

MAIN RELAY

ELECTRONIC THROTTLE

CONTROL RELAY

BATTERY

: TERMINAL No. OPTIONAL ARRANGEMENT

ELECTRONIC THROTTLE

CONTROL

EN(H4DOTC)(diag)-378

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step

Check

Yes

CHECK ELECTRONIC THROTTLE CON-
TROL RELAY.
1) Turn the ignition switch to OFF.
2) Remove the electronic throttle control relay.
3) Connect the battery to terminals No. 31 and
No. 32 of electronic throttle control relay.
4) Measure the resistance between electronic
throttle control relay terminals.

Terminals

No. 29 — No. 30:

Is the resistance less than 1 Ω? Go to step

Replace the elec-
tronic throttle con-
trol relay. <Ref. to
FU(STI)-64, Elec-
tronic Throttle
Control Relay.>
<Ref. to FU(w/o
STI)-62, Elec-
tronic Throttle
Control Relay.>

CHECK POWER SUPPLY OF ELECTRONIC
THROTTLE CONTROL RELAY.
Measure the voltage between electronic throttle
control relay connector and chassis ground.

Connector & terminal

(B220) No. 29 (+) — Chassis ground (–):

Is the voltage 10 V or more?

Go to step

Repair the open or
ground short circuit
of power supply
circuit.

CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL RE-
LAY CONNECTOR.
1) Disconnect the connector from ECM.
2) Turn the ignition switch to ON.
3) Measure the voltage between electronic
throttle control relay connector and chassis
ground.

Connector & terminal

(B220) No. 32 (+) — Chassis ground (–):

Is the voltage 10 V or more?

Repair the short
circuit to power in
the harness
between ECM con-
nector and elec-
tronic throttle
control relay con-
nector.

Go to step

CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL RE-
LAY CONNECTOR.
1) Turn the ignition switch to OFF.
2) Measure the resistance between electronic
throttle control relay connector and chassis
ground.

Connector & terminal

(B220) No. 32 — Chassis ground:
(B220) No. 30 — Chassis ground:

Is the resistance 1 MΩ or
more?

Go to step

Repair the short
circuit to ground in
harness between
ECM connector
and electronic
throttle control
relay connector.

CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL RE-
LAY CONNECTOR.
Measure the resistance between ECM connec-
tor and electronic throttle control relay connec-
tor.

Connector & terminal

(B135) No. 17 — (B220) No. 32:
(B135) No. 7 — (B220) No. 30:

Is the resistance less than 1 Ω? Repair the poor

contact of ECM
connector.

Repair the open
circuit in harness
between ECM con-
nector and elec-
tronic throttle
control relay con-
nector.