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HOMESERVICE MANUALSPONTIAC2008GRAND PRIX BASEREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 24 (BATTERY, CHARGING SYSTEM AND STARTING SYSTEM)DIAGNOSTIC INFORMATION AND PROCEDURESCHARGING SYSTEM TEST
2008 Pontiac Grand Prix Base

Charging System Test

2008 Pontiac Grand Prix BaseSECTION Charging System Test
WARNING: This page is about a different car, the 2007 Hummer H2. However, it is still accessible from the selected car via links, so may be relevant.
Charging System Test

Step Action Value(s) Yes No
1 Did you perform the Diagnostic System Check - Vehicle? - Go to Step 2  Go to Diagnostic System Check - Vehicle
2 Start the engine. Observe the charge indicator on the instrument panel cluster (IPC).
Does the charge indicator illuminate or message center (DIC) display a charging system message?		 - Go to Step 3  Go to Symptoms - Engine Electrical 
3
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?		 - Go to Step 6  Go to Step 4 
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 
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 
6
  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?		 - Go to Step 7  Go to Step 13 
7
  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?		 - Go to Step 15  Go to Step 8 
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 its 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?		 - Go to Step 15  Go to Step 9 
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 .
Does the voltage measure greater than the specified value?		 0.5 V Go to Step 11  Go to Step 10 
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 .
Does the voltage measure greater than the specified value?		 0.5 V Go to Step 12  Go to Step 16 
11 Repair the high resistance or an open in the output circuit of the generator. Refer to Circuit Testing and to Wiring Repairs .
Did you complete the repair?		 - Go to Step 16  -
12 Repair the high resistance or open in the ground circuit of the generator. Refer to Circuit Testing and to Wiring Repairs .
Did you complete the repair?		 - Go to Step 16  -
13
  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?		 - Go to Step 15  Go to Step 14 
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?		 - Go to Step 3  -
15 Replace the generator. Refer to Generator Replacement .
Did you complete the replacement?		 - Go to Step 16  -
16 Operate the vehicle in order to verify the repair.
Did you correct the condition?		 - System OK Go to Step 2 
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.