Grand Prix V8-5.3L (2007)
5. Verify that a test lamp illuminates between the relay switch B+ and ground.
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If the test lamp does not illuminate, test the relay switch B+ circuit for a short to ground or an open/high resistance. If the circuits test normal
and the fuse for the ignition 1 voltage circuit is open, test the ignition 1 voltage circuit to the ECM for a short to ground. If the circuit tests
normal, replace the ECM.
6. Connect a test lamp between the relay coil B+ and the relay coil control circuit.
7. Ignition ON, command the powertrain relay ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the
commanded states.
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If the test lamp is always ON, test the relay coil control circuit for a short to ground. If the circuit tests normal, replace the ECM.
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If the test lamp is always OFF, test the relay coil control circuit for a short to voltage or an open/high resistance. If the circuit tests normal,
replace the ECM.
8. Connect a 20-amp fused jumper wire between the relay switch B+ and the relay ignition 1 voltage circuit.
9. Ignition ON, engine OFF, monitor the EC Ignition Relay Feedback parameter with a scan tool. The parameter should display B+.
^
If the parameter does not display B+, test the ignition 1 voltage circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
10. If all circuits test normal, test or replace the relay.
Component Testing
1. Ignition OFF, disconnect the powertrain relay.
2. Test for 65-110 ohms of resistance between terminals 85 and 86 of the relay.
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If the resistance is not within the specified range, replace the relay.
3. Test for infinite resistance between following terminals:
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Terminal 30 and 86
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Terminal 30 and 87
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Terminal 30 and 85
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Terminal 85 and 87
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If not the specified value, replace the relay.
4. Install a 20-amp fused jumper wire between relay terminal 85 and 12 volts. Install a jumper wire between relay terminal 86 and ground. Test for
less than 1 ohm of resistance between terminals 30 and 87.
^
If greater than the specified range, replace the relay.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure. See: Computers and Control Systems/Testing and
Inspection/Diagnostic Trouble Code Tests and Associated Procedures/Verification Tests and Procedures
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Relay Replacement (Attached to Wire Harness) Relay Replacement (Within an Electrical Center)
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Junction Block Replacement - Accessory Wiring
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Control Module References for ECM replacement, setup, and programming. See: Testing and Inspection/Programming and Relearning
