Did you perform the Diagnostic System Check - Vehicle?

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Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

Start the engine. Observe the charge indicator on the instrument cluster (IPC) .

Does the charge indicator illuminate or message center (DIC) display a charging system message?

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Go to Step 3

Go to Symptoms - Engine Electrical

Important: The green POWER lamp of the tester should remain illuminated while the tester is being used.

1. Turn OFF the ignition.
2. Connect the red lead of the J 41450-B Universal CS Generator Test Harness to the generator output terminal.
3. Connect the black lead of the J 41450-B to the metal generator housing.

Does the green POWER lamp on the tester illuminate?

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Go to Step 6

Go to Step 4

Measure the voltage from the output terminal of the generator to the generator metal housing.

Does the voltage measure equal to the specified value?

12 V

Go to Step 14

Go to Step 5

Measure the voltage from the output terminal of the generator to the battery negative terminal.

Does the voltage measure equal to the specified value?

12 V

Go to Step 12

Go to Step 11

1. Turn OFF completely the load tool before connecting or disconnecting a carbon pile load tester to the battery. Otherwise, sparking at the terminals could cause battery gasses to explode.
2. Connect a carbon pile tester to the vehicle.

Important: Ensure that all generator output circuit wires pass through the inductive probe.

3. Connect an inductive ammeter to the output circuit of the generator.
4. Disconnect the generator harness connector.
5. Locate the matching harness connector on the J 41450-B , and connect the connector to the generator.

Does the red DIAGNOSTIC lamp on the tester illuminate?

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Go to Step 7

Go to Step 13

1. Start the engine and allow it to idle for 30 seconds.
2. Increase the engine speed to 2,500 RPM.

Does the red DIAGNOSTIC lamp on the tester illuminate?

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Go to Step 15

Go to Step 8

1. Maintain the engine speed at 2,500 RPM.

Important: If the generator is not capable of producing the Load Test amps, operate the generator at it's maximum possible output.

2. Turn ON the load of the carbon pile tester and increase the load until the generator output is equal to the Load Test value given in Generator Usage.

Does the red DIAGNOSTIC lamp on the tester illuminate?

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Go to Step 15

Go to Step 9

1. Maintain the engine speed at 2,500 RPM and continue to operate the generator at the load test value.
2. Measure the voltage drop from the output terminal of the generator to the positive terminal on the battery. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Does the voltage measure greater than the specified value?

0.5 V

Go to Step 11

Go to Step 10

1. Maintain the engine speed at 2,500 RPM and continue to operate the generator at the load test value.
2. Measure the voltage drop from the battery negative terminal to the metal housing of the generator. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Does the voltage measure greater than the specified value?

0.5 V

Go to Step 12

Go to Step 16

Repair the high resistance or an open in the output circuit of the generator. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you complete the repair?

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Go to Step 16

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Repair the high resistance or open in the ground circuit of the generator. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you complete the repair?

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Go to Step 16

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1. Disconnect the J 41450-B tester harness connector from the generator, but leave the alligator clips connected so that the green POWER lamp remains illuminated.
2. Connect a jumper lead, with an in-line 100-ohm resistor between the J 41450-B tester harness connector terminal B of the generator and a good ground. Refer to Engine Electrical Connector End Views .

Does the red DIAGNOSTIC lamp illuminate?

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Go to Step 15

Go to Step 14

There is a problem with the J 41450-B . Refer to the manufacturers instructions, how to test the J 41450-B for proper operation.

Has the J 41450-B tester been replaced?

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Go to Step 3

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Replace the generator. Refer to Generator Replacement .

Did you complete the replacement?

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Go to Step 16

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Operate the vehicle in order to verify the repair.

Did you correct the condition?

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System OK

Go to Step 2

Did you perform the Diagnostic System Check - Vehicle?

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Go to Step 2

Go to Diagnostic System Check - Vehicle

With ignition OFF, install the Midtronics Digital Battery Analyzer and verify the condition of the battery.

Is the battery sufficiently charged for testing?

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Go to Step 3

Go to Battery Inspection/Test

1. Disconnect the Midtronics Digital Battery Analyzer.
2. Connect the Sun Vat 40 tester or equivalent to the battery.
3. Turn the ignition to the OFF/LOCK position.
4. Observe and record the battery voltage reading at the battery terminals on the Sun Vat 40 tester.
5. Start the engine and observe the system voltage reading on the tester.

Does the voltage increase from the first specified (engine OFF) to the second (engine ON specified range)?

Engine Off = B+

Engine On = 13.9-15.5 V

Go to Step 4

Go to Step 6

1. Turn on the following accessories:

•	Headlights - HI beams

•	A/C on Max

•	Blower Fan - On high

•	Rear window defogger

•	Heated seats (If equipped)

2. Maintain engine speed at 2500 RPM.

Is voltage still within the specified value?

13.9-15.5 V

Go to Step 5

Go to Step 6

1. Turn OFF all accessories.
2. Turn OFF the ignition.
3. Connect a carbon pile tester to the vehicle.

Important: When measuring generator output current, be sure the inductive probe encircles the generator output wire.

4. Connect an inductive ammeter probe to the output circuit of the generator.
5. Start the engine.
6. Increase engine speed to 2,500 RPM.
7. Adjust the carbon pile as necessary in order to obtain the maximum current output.

Is the generator output greater than or equal to the load test value as specified in Generator Usage ?

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System OK

Go to Step 10

1. Turn the engine OFF.
2. Disconnect the generator harness connector.
3. Turn the ignition to the ON position.
4. Using a DMM, measure the voltage on the L-terminal circuit.

Is the voltage greater than the specified value?

0 V

Go to Step 11

Go to Step 7

1. Turn the engine OFF.
2. Start the engine and check the voltage on the L-terminal.

Is the voltage within the specified value?

3 V or above

Go to Step 8

Go to Step 12

1. Turn engine OFF.
2. Turn ignition switch to ON position.
3. Using the scan tool, observe the duty cycle in the F-terminal signal parameter.

Does the scan tool display near the indicated value?

0%

Go to Step 9

Go to Step 13

Connect a test lamp to B+ and repeatedly touch the F-terminal at the generator harness connector while monitoring the GEN-F terminal signal parameter on the scan tool.

Does the scan tool indicate that the generator PWM is above the specified range?

90%

Go to Step 10

Go to Step 14

1. Turn the engine OFF.
2. Inspect the generator B+ output terminal at the generator for an open or high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

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Go to Step 19

Go to Step 15

Test the L-terminal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

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Go to Step 19

Go to Step 16

Test the L-terminal circuit for open or short to ground. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

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Go to Step 19

Go to Step 16

Test the GEN-F terminal for a short to voltage. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

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Go to Step 19

Go to Step 16

Test the GEN-F terminal circuit for an open or short to ground. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

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Go to Step 19

Go to Step 16

Inspect for poor connections at the generator. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

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Go to Step 19

Go to Step 18

Inspect for poor connections at the harness connector of the generator battery control module (GBCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

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Go to Step 19

Go to Step 17

Replace the GBCM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

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Go to Step 19

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Replace the generator. Refer to Generator Replacement .

Did you complete the replacement?

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Go to Step 19

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Operate the vehicle in order to verify the repair.

Did you correct the condition?

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System OK

Go to Step 2