Mazda CX 7. Manual - part 134

CHARGING SYSTEM [L3 WITH TC]

01-17–7

01-17

9. Turn the following electrical loads on and verify that the current reading increases more than the minimum 

value indicated below.

— If it is not as specified, go to the PCM and generator shearing inspection. (See 01-17-7 PCM and generator 

shearing inspection.)

• Headlights (high-beam)

• Blower motor (HI)

• Rear window defroster

• Brake lights

Generator generated current minimum value

70 % of the nominal output current (nominal output current: 110 A)
[Ambient temp. 20 

°C {68 °F}, voltage 13.0— 15.0 V, both engine and generator are hot]

PCM and generator shearing inspection

1. Connect the M-MDS to the DLC-2.

2. Inspect as follows: 

DLC-2

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Step

Inspection

Action

1

Measure the generator terminal B voltage when the 
electrical loads

*1

 are on and off.

15 V or more

Go to Step 2.

13— 15 V

Normal

*2

13 V or less

Go to Step 3.

2

Monitor the ALTT V PID using the M-MDS, or measure the 
voltage of PCM terminal 2AJ using a tester. Is the voltage 
between 13 and 15 V ?

Yes

Go to Step 4.

No

PCM input error.

3

Monitor the ALTT V PID using the M-MDS, or measure the 
voltage of PCM terminal 2AJ using a tester. Is the voltage 
between 13 and 15 V ?

Yes

Go to Step 5.

No

PCM input error.

4

Monitor the ALTF PID using the M-MDS, or calculate the 
duty value of the PCM terminal 2AI using an oscilloscope. 
Is the duty value 100 % ?

Yes

PCM input error.

No

PCM, generator, or 
both are not 
normal.

0V

A

B

B

A

x 100 (%) = DUTY (%)

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CHARGING SYSTEM [L3 WITH TC]

01-17–8

*1

: Headlights, blower motor, rear window defroster, and brake lights.

*2

: If the generator field coil duty value does not change when electrical loads (such as headlights, blower motor, 

rear window defroster, brake lights) are on or off, inspection with discharged battery is needed.

Generator Inner Parts
Rotor

1. Measure the resistance between the slip rings 

using a tester.

• If not within the specification, replace the 

rotor.

Generator rotor resistance (between slip 

rings) [20 

°C {68 °F}]

1.8— 2.2 ohm

2. Verify that there is no continuity between the slip 

ring and core using a tester.

• If there is continuity, replace the rotor.

3. Inspect the slip ring surface condition.

• If the slip ring surface is rough, use a lathe or 

fine sandpaper to smooth it.

5

Monitor the ALTF PID using the M-MDS, or calculate the 
duty value of the PCM terminal 2AI using an oscilloscope. 
Is the duty value 0 % ?

Yes

PCM input error.

No

PCM, generator, or 
both are not 
normal.

Step

Inspection

Action

0V

A

B

B

A

x 100 (%) = DUTY (%)

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CHARGING SYSTEM [L3 WITH TC]

01-17–9

01-17

Stator coil

1. Verify that the continuity is as indicated in the 

table.

• If there is any malfunction, replace the stator.

2. Verify that there is no continuity between the 

stator coil leads and core using a tester.

• If there is continuity, replace the stator coil.

Brush

1. Inspect brushes for wear.

• If any brush is worn almost to or beyond the 

limit, replace all of the brushes.

Generator brush length

Standard: 22.5 mm {0.89 in}
Minimum: 5.0 mm {0.20 in}

1

2

3

4

5

6

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Terminal

: Continuity

1

2

3

4

5

6

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MINIMUM

STANDARD

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CHARGING SYSTEM [L3 WITH TC]

01-17–10

Brush spring

1. Measure the force of the brush spring using a spring pressure gauge.
2. Read the spring pressure gauge at the brush tip 

projection of 2 mm {0.079 in}.

• Replace the brush spring if necessary.

Generator brush spring force

Standard: 4.1— 5.3 N {0.42— 0.54 kgf, 0.92— 

1.19 lbf}

Minimum: 1.7 N {0.17 kgf, 0.38 lbf}

Rectifier (Using an analog circuit tester)

1. Inspect for continuity of the diodes using an 

analog circuit tester.

• If not as specified, replace the rectifier.

Specification

Rectifier (Using a digital circuit tester)

1. Inspect for continuity of the diodes using a digital circuit tester.

• If not as specified, replace the rectifier.

Specification

Bearing

1. Inspect for abnormal noise, looseness, and 

sticking.

• Replace the bearing if necessary.

End Of Sie

2 mm
{0.079 in}

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Negative

Positive

Continuity

E

P1, P2, P3, P4, 

P5, P6

Yes

B

No

P1, P2, P3, P4, 

P5, P6

E

No

B

Yes

P4

P5

P6

P3

P2

P1

E

B

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Negative

Positive

Continuity

E

P1, P2, P3, P4, 

P5, P6

No

B

Yes

P1, P2, P3, P4, 

P5, P6

E

Yes

B

No

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