Mazda CX 7. Manual - part 347

ON-BOARD DIAGNOSTIC [BCM]

09-02F–23

09-02F

DTC C1284[BCM]

id0902f5838400

Diagnostic procedure

DTC C1284

Oil pressure switch circuit failure

DETECTION 
CONDITION

Open circuit in wiring harness between BCM and oil pressure switch

POSSIBLE 
CAUSE

• Open circuit in wiring harness between BCM terminal 1G and oil pressure switch terminal A

• Oil pressure switch malfunction

• BCM malfunction

STEP

INSPECTION

ACTION

1

INSPECT OIL PRESSURE SWITCH 
CONNECTOR

• Turn the ignition switch off.

• Disconnect the oil pressure switch 

connector.

• Inspect the oil pressure switch connector 

terminals for poor connection (such as 
damaged/pulled-out pins, and corrosion).

• Is there any malfunction?

Yes

Repair or replace the terminal, then go to Step 5.

No

Go to the next step.

2

INSPECT BCM CONNECTOR

• Disconnect the BCM connector.

• Inspect the BCM connector terminals for 

poor connection (such as damaged/pulled-
out pins, and corrosion).

• Is there any malfunction?

Yes

Repair or replace the terminal, then go to Step 5.

No

Go to the next step.

3

INSPECT OIL PRESSURE SWITCH SIGNAL 
CIRCUIT FOR OPEN CIRCUIT

• Inspect for continuity between BCM terminal 

1G (wiring harness-side) and oil pressure 
switch terminal A (wiring harness-side).

• Is there continuity?

Yes

Go to the next step.

No

Repair or replace the wiring harness for a possible open 
circuit, then go to Step 5.

4

INSPECT OIL PRESSURE SWITCH

• Inspect the oil pressure switch.

 (See 09-22-14 OIL PRESSURE SWITCH 
INSPECTION.)

• Is there any malfunction?

Yes

Replace the oil pressure switch, then go to the next step.

No

Go to the next step.

5

VERIFY TROUBLESHOOTING COMPLETED

• Make sure to reconnect all disconnected 

connectors.

• Clear the DTC from the BCM memory using 

the M-MDS.

• Perform the self-test.

 (See 09-02F-26 BCM SELF-TEST[BCM].)

• Is the same DTC present?

Yes

Replace the BCM.
 (See 09-40-1 BODY CONTROL MODULE (BCM) 
REMOVAL/INSTALLATION.)

No

DTC troubleshooting completed.

A

OIL PRESSURE SWITCH

BCM

1G

A

OIL PRESSURE SWITCH WIRING 

HARNESS-SIDE CONNECTOR

BCM WIRING HARNESS-SIDE  

CONNECTOR

1E

1G

1I

1K

1M

1O

1A

1C

1N

1L

1P

1H

1D

1B

1F

1J

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ON-BOARD DIAGNOSTIC [BCM]

09-02F–24

End Of Sie

DTC C1295, C1307, C1441, C1442, C1443, C1444, C144A, C144C[BCM]

id0902f5839800

DTC C1295, C1307, C1441, C1442, C1443, C1444, C144A, C144C

Steering angle sensor system

DETECTION 
CONDITION

C1295

• BCM detects steering angle sensor internal abnormality (signal overflow)

C1307

• BCM detects steering angle sensor internal abnormality (signal jump)

C1441, C1442, C144C

• Open circuit in wiring harness between BCM and steering angle sensor

C1443, C1444, C144A

• Short to GND in wiring harness between BCM and steering angle sensor

POSSIBLE 
CAUSE

• Improper installation or positioning of the steering angle sensor

• Steering wheel is off-center

• Open circuit in wiring harness between BCM terminal 3S and steering angle sensor terminal F

• Open circuit or short to power supply in wiring harness between BCM terminal 3Q and steering angle 

sensor terminal A

• Open circuit or short to power supply in wiring harness between BCM terminal 3O and steering angle 

sensor terminal C

• Open circuit or short to power supply in wiring harness between BCM terminal 3M and steering angle 

sensor terminal E

• Open circuit or short to power supply in wiring harness between BCM terminal 3K and steering angle 

sensor terminal D

• Open circuit in wiring harness between BCM terminal 3I and steering angle sensor terminal B

• Short to GND in wiring harness between BCM terminal 3S and steering angle sensor terminal F

• Short to GND in wiring harness between BCM terminal 3Q and steering angle sensor terminal A

• Short to GND in wiring harness between BCM terminal 3O and steering angle sensor terminal C

• Short to GND in wiring harness between BCM terminal 3M and steering angle sensor terminal E

• Short to GND in wiring harness between BCM terminal 3K and steering angle sensor terminal D

• Steering angle sensor signal circuit short each other

• Steering angle sensor malfunction

• BCM malfunction

3K

D

3I

B

3O

C

3M

E

3S

F

3Q

A

E

A

C

D

B

F

3E

3G

3I

3K

3M

3O

3A

3C

3N 3L

3P

3H

3D 3B

3F

3J

3Q

3R

3S

3T

3U

3V

3W

3X

BCM

STEERING ANGLE SENSOR WIRING 

HARNESS-SIDE CONNECTOR

STEERING ANGLE SENSOR

BCM WIRING HARNESS-SIDE 

CONNECTOR

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ON-BOARD DIAGNOSTIC [BCM]

09-02F–25

09-02F

Diagnostic procedure

STEP

INSPECTION

ACTION

1

INSPECT STEERING WHEEL FOR OFF-
CENTER

• Drive the vehicle and inspect the steering 

wheel position while driving in a straight line.

• Is the steering wheel off-center?

Yes

Inspect and adjust the front wheel alignment to correct the 
steering wheel alignment, then go to Step 9.
(See 02-11-2 FRONT WHEEL ALIGNMENT.)

No

Go to the next step.

2

INSPECT STEERING ANGLE SENSOR 
POWER SUPPLY CIRCUIT FOR OPEN

• Turn the ignition switch to the ON position.

• Measure the voltage between the steering 

angle sensor terminal F and body GND.

• Is the voltage 5 V?

Yes

Go to the next step.

No

Repair or replace the wiring harness, then go to Step 9.

3

INSPECT STEERING ANGLE SENSOR GND 
CIRCUIT FOR OPEN

• Turn the ignition switch off.

• Disconnect the steering angle sensor  

connector.

• Inspect for continuity between the steering 

angle sensor terminal B (wiring harness-
side) and body GND.

• Is there continuity?

Yes

Go to the next step.

No

Repair or replace the wiring harness, then go to Step 9.

4

INSPECT STEERING ANGLE SENSOR 
SIGNAL CIRCUIT FOR OPEN

• Disconnect the BCM connector.

• Inspect for continuity between the following 

terminals:
— BCM terminal 3Q— steering angle sensor 

terminal A (wiring harness-side)

— BCM terminal 3O— steering angle sensor 

terminal C (wiring harness-side)

— BCM terminal 3M— steering angle sensor 

terminal E (wiring harness-side)

— BCM terminal 3K— steering angle sensor 

terminal D (wiring harness-side)

• Is there continuity?

Yes

Go to the next step.

No

Repair or replace the wiring harness, then go to Step 9.

5

INSPECT STEERING ANGLE SENSOR 
SIGNAL CIRCUIT FOR SHORT TO GND

• Inspect for continuity between the following 

terminals  and body GND:

— Steering angle sensor terminal A (wiring 

harness-side)

— Steering angle sensor terminal C (wiring 

harness-side)

— Steering angle sensor terminal E (wiring 

harness-side)

— Steering angle sensor terminal D (wiring 

harness-side)

• Is there continuity?

Yes

Repair or replace the wiring harness, then go to Step 9.

No

Go to the next step.

6

INSPECT STEERING ANGLE SENSOR 
SIGNAL CIRCUIT FOR SHORT TO POWER 
SUPPLY

• Measure voltage between the following and 

body GND:
— Steering angle sensor terminal A (wiring 

harness-side)

— Steering angle sensor terminal C (wiring 

harness-side)

— Steering angle sensor terminal E (wiring 

harness-side)

— Steering angle sensor terminal D (wiring 

harness-side)

• Is the voltage 1 V or less? 

Yes

Go to the next step.

No

Repair or replace the wiring harness, then go to Step 9.

7

INSPECT FOR IMPROPER INSTALLATION 
OF STEERING ANGLE SENSOR

• Is the installation normal?

Yes

Go to the next step.

No

Repair installation or replace the steering angle sensor, then 
go to Step 9.

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ON-BOARD DIAGNOSTIC [BCM]

09-02F–26

End Of Sie

DTC C1937[BCM]

id0902f5839300

Diagnostic procedure

End Of Sie

BCM SELF-TEST[BCM]

id0902f5830600

1. Connect the M-MDS to the DLC-2.
2. Set up the M-MDS (including the vehicle 

recognition).

3. Verify the following vehicle conditions:

• All the switches are turned off (except the 

ignition switch).

• All the doors, hood, and liftgate are closed.

• All the doors, and liftgate are unlocked.

• Parking brake lever is pulled.

4. Start the engine.

Note

• If the engine is not running, the BCM 

determines that the oil pressure switch 
malfunction.

5. Perform procedures according to directions on the M-MDS screen.
6. Verify if any DTCs are displayed.

• If any DTCs are displayed, perform the troubleshooting according to the corresponding DTC inspection.

7. Disconnect the M-MDS.

End Of Sie

8

INSPECT STEERING ANGLE SENSOR

• Inspect the steering angle sensor.

(See 09-40-8 STEERING ANGLE SENSOR 
INITIALIZATION PROCEDURE.)

• Is the steering angle sensor normal?

Yes

Go to the next step.

No

Replace the steering angle sensor, then go to Step 9.

9

VERIFY TROUBLESHOOTING COMPLETED

• Make sure to reconnect all disconnected 

connectors.

• Clear the DTC from the BCM memory using 

the M-MDS.

• Start the engine and drive the vehicle at 10 

km/h {6.2 mph} or more.

• Is the same DTC present?

Yes

Replace the BCM.
 (See 09-40-1 BODY CONTROL MODULE (BCM) 
REMOVAL/INSTALLATION.)

No

DTC troubleshooting completed.

STEP

INSPECTION

ACTION

DTC C1937

Steering wheel angle sensor offset failure

DETECTION 
CONDITION

BCM lost steering angle initialization position

POSSIBLE 
CAUSE

• Steering wheel is operated suddenly during sleep control

• Steering angle sensor malfunction

• BCM malfunction

STEP

INSPECTION

ACTION

1

PERFORM STEERING ANGLE SENSOR 
INITIALIZATION

• Perform steering angle sensor initialization.

 (See 09-40-8 STEERING ANGLE SENSOR 
INITIALIZATION PROCEDURE.)

• TCS OFF light and DSC/TCS indicator light 

go out?

Yes

Inspect the steering angle sensor and related wiring 
harness.

• Repair ore replace if necessary.

Go to the next step.

No

Go to the next step.

2

VERIFY TROUBLESHOOTING COMPLETED

• Make sure to reconnect all disconnected 

connectors.

• Clear the DTC from the BCM memory using 

the M-MDS.

• Turn the ignition switch to LOCK position 

then ON position.

• Is the same DTC present?

Yes

Replace the BCM.
 (See 09-40-1 BODY CONTROL MODULE (BCM) 
REMOVAL/INSTALLATION.)

No

DTC troubleshooting completed.

DLC-2

acxuuw00001913

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