Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Service manual — part 452

6MT(diag)-19

List of Diagnostic Trouble Code (DTC)

MANUAL TRANSMISSION AND DIFFERENTIAL (DIAGNOSTICS)

12.List of Diagnostic Trouble Code (DTC)

A: LIST

1. SUBARU SELECT MONITOR DISPLAY

DTC

Item

Content of diagnosis

Reference

P1521

Brake Switch Circuit Range/
Performance Problem (High
Input)

Stop light switch circuit is open or
shorted.

<Ref. to 6MT(diag)-20, DTC P1521 BRAKE
SWITCH CIRCUIT RANGE/PERFORMANCE
PROBLEM (HIGH INPUT), Diagnostic Proce-
dure with Diagnostic Trouble Code (DTC).>

P1720 DCCD CAN System Circuit

CAN communication circuit is open or
shorted.

<Ref. to 6MT(diag)-21, DTC P1720 DCCD
CAN SYSTEM CIRCUIT, Diagnostic Procedure
with Diagnostic Trouble Code (DTC).>

P1767 DCCD Steering Angle Sensor

Open, short or communication failure
of the steering angle sensor circuit

<Ref. to 6MT(diag)-22, DTC P1767 DCCD
STEERING ANGLE SENSOR, Diagnostic Pro-
cedure with Diagnostic Trouble Code (DTC).>

P1769

Yaw Rate & Lateral G Sensor
Malfunction

Yaw rate & lateral G sensor malfunc-
tion

<Ref. to 6MT(diag)-23, DTC P1769 YAW RATE
& LATERAL G SENSOR MALFUNCTION,
Diagnostic Procedure with Diagnostic Trouble
Code (DTC).>

P1875 Circuit of Center Diff

Open or short in the driver’s control
center differential circuit

<Ref. to 6MT(diag)-24, DTC P1875 CIRCUIT
OF CENTER DIFF, Diagnostic Procedure with
Diagnostic Trouble Code (DTC).>

6MT(diag)-20

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

MANUAL TRANSMISSION AND DIFFERENTIAL (DIAGNOSTICS)

13.Diagnostic Procedure with Diagnostic Trouble Code (DTC)

A: DTC P1521 BRAKE SWITCH CIRCUIT RANGE/PERFORMANCE PROBLEM

(HIGH INPUT)

DIAGNOSIS:

Stop light switch circuit is open or shorted.

TROUBLE SYMPTOM:

ABS does not operate.

Step

Check

Yes

No

1

CHECK DTC.

Does the DTC related to stop
light SW appear in the VDC
diagnostics test mode?

Perform the diag-
nosis according to
DTC.

Go to step

2.

2

CHECK IGNITION POWER SUPPLY CIRCUIT
OF DCCD CONTROL MODULE.
1) Connect the Subaru Select Monitor to the
vehicle.
2) Turn the ignition switch to ON.
3) Read the data of «Battery voltage» using
Subaru Select Monitor.

Is the voltage 11 V or more?

Go to step

3.

Repair the open
circuit of harness
between fuse (F/B
No. 12) and DCCD
control module, or
between fuse (F/B
No. 12) and bat-
tery.

3

CHECK DTC.

Is DTC P1720 displayed?

Perform the diag-
nosis according to
DTC.

Go to step

4.

4

CHECK DCCD CONTROL MODULE.
1) Turn the ignition switch to ON.
2) Read the data of «Stop Light Switch» using
Subaru Select Monitor.

Does the «Stop Light Switch»
change to ON/OFF according
to the depressing/releasing
operation of the brake?

Go to step

5.

Check the poor
contact.

5

CHECK OTHER DTC.

Is a DTC other than DTC P1521
displayed?

Perform the diag-
nosis according to
DTC.

The stop light
switch is currently
normal.

6MT(diag)-21

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

MANUAL TRANSMISSION AND DIFFERENTIAL (DIAGNOSTICS)

B: DTC P1720 DCCD CAN SYSTEM CIRCUIT

NOTE:

Refer to “LAN SYSTEM” for diagnostic procedure. <Ref. to LAN(diag)-55, DTC U1216 HIGH-SPEED CAN

(DCCD) DATA ERROR, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>

6MT(diag)-22

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

MANUAL TRANSMISSION AND DIFFERENTIAL (DIAGNOSTICS)

C: DTC P1767 DCCD STEERING ANGLE SENSOR

DIAGNOSIS:

Open, short or communication failure of the steering angle sensor circuit

TROUBLE SYMPTOM:

A tight corner braking symptom occurs.

Step

Check

Yes

No

1

CHECK DTC.

Does the DTC related to steer-
ing angle sensor appear in the
VDC diagnostics test mode?

Perform the diag-
nosis according to
DTC.

Go to step

2.

2

CHECK IGNITION POWER SUPPLY CIRCUIT
OF DCCD CONTROL MODULE.
1) Connect the Subaru Select Monitor to the
vehicle.
2) Turn the ignition switch to ON.
3) Read the data of «Battery voltage» using
Subaru Select Monitor.

Is the voltage 11 V or more?

Go to step

3.

Repair the open
circuit of harness
between fuse (F/B
No. 12) and DCCD
control module, or
between fuse (F/B
No. 12) and bat-
tery.

3

CHECK DTC.

Is DTC P1720 displayed?

Perform the diag-
nosis according to
DTC.

Go to step

4.

4

CHECK DCCD CONTROL MODULE.
1) Turn the ignition switch to ON.
2) Read the data of «Steering Angle Sensor»
using Subaru Select Monitor.

Does the Subaru Select Moni-
tor value change according to
the input from the steering to
the right and left?

Go to step

5.

Go to step

6.

5

CHECK DTC.
1) Clear the memory.
2) Start the engine.
3) Read the DTC.

Is DTC P1767 displayed?

Replace the steer-
ing angle sensor.

Go to step

6.

6

CHECK OTHER DTC.

Is a DTC other than DTC P1767
displayed?

Perform the diag-
nosis according to
DTC.

The steering angle
sensor circuit is
currently operating
properly.