Noise from a generator may be because of electrical noise or because of mechanical noise. Usually, electrical noise or magnetic whine varies with the ampere load placed on the generator and is a normal operating characteristic of all generators. If diagnosing a noisy generator, loose components or misaligned components around the generator may transmit the noise into the passenger compartment. Replacement of the generator may not resolve the condition.

1

Test the generator for correct operation using an appropriate generator tester. Refer to Charging System Check .

Is the generator operating correctly?

Go to Step 2

Go to Step 13

1. Start the engine. Verify that the noise can be heard.
2. Disconnect the connector from the generator.
3. Listen for the noise.

Has the noise stopped?

Go to Step 12

Go to Step 3

1. Turn OFF the engine.
2. Remove the drive belt. Refer to Drive Belt Replacement 1.0L or to Drive Belt Replacement 1.3L in Engine Mechanical.
3. Spin the generator pulley.

Does the generator shaft smoothly spin without any roughness or without any grinding noise?

Go to Step 4

Go to Step 13

Inspect the generator for a loose pulley and for a loose pulley nut.

Is the generator pulley or the pulley nut loose?

Go to Step 5

Go to Step 7

1. Remove the generator pulley.
2. Inspect the pulley and the shaft for damage or for signs of overheating because of a slipping pulley.

Is the pulley or the shaft damaged?

Go to Step 13

Go to Step 6

1. Install the pulley.
2. Tighten the generator pulley nut to 65 N·m (48 lb ft).
3. Install the drive belt. Refer to Drive Belt Replacement 1.0L or to Drive Belt Replacement 1.3L in Engine Mechanical.
4. Start the engine.

Has the noise decreased or stopped?

System OK

Go to Step 7

1. Loosen all of the generator mounting bolts.
2. Tighten the generator mounting bolts to specifications and in the proper sequence if necessary. Refer to Generator Replacement .
3. Install the drive belt. Refer to Drive Belt Replacement 1.0L or to Drive Belt Replacement 1.3L in Engine Mechanical.
4. Start the engine.

Has the noise decreased or stopped?

System OK

Go to Step 8

Inspect the generator for the following conditions:

Do the connections pull the generator, or do any hoses, etc. rest on the generator?

Go to Step 9

Go to Step 10

1. Reroute the connections in order to relieve the tension.
2. Reroute the hoses, etc. away from the generator.
3. Start the engine.

Has the noise decreased or stopped?

System OK

Go to Step 10

Check the drive belt for correct tension. Refer to Drive Belt Replacement 1.0L or to Drive Belt Replacement 1.3L in Engine Mechanical.

Is the drive belt loose?

Go to Step 11

Go to Step 12

1. Adjust the drive belt tension. Refer to Drive Belt Replacement 1.0L or to Drive Belt Replacement 1.3L in Engine Mechanical.
2. Start the engine.

Has the noise decreased or stopped?

System OK

Go to Step 12

Compare the vehicle with a known good vehicle.

Do both vehicles make the same noise?

System OK

Go to Step 13

Important: Before replacing the generator, eliminate all other possible sources of objectionable noise. Replacing the generator may not change the noise level, if the noise is a characteristic of the generator or of the mounting configuration.

Replace the generator. Refer to Generator Replacement .

Has the noise decreased or stopped?

System OK

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