Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSBUICK2006TERRAZA CXL, 3.5 L, AWDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 234 (ENGINE CONTROL SYSTEM - 5.3L - DTC P1682 TO DTC P3401)DTC P1682CIRCUIT/SYSTEM TESTING
2006 Buick Terraza CXL, 3.5 L, AWD
Circuit/System Testing
2006 Buick Terraza CXL, 3.5 L, AWDSECTION Circuit/System Testing
WARNING: This page is about a different car, the 2006 Chevrolet Monte Carlo and 2006 Chevrolet Impala. However, it is still accessible from the selected car via links, so may be relevant.
- If DTCs P0685, P0689, or P0690 are set, test and repair those DTCs first.
- With the ignition ON, and the engine OFF, test for ignition 1 voltage at both test points of the ECM IGN fuse in the underhood fuse block.IMPORTANT: The ignition main relay that is shown on the electrical wiring schematic is not serviceable. It is soldered to the bus bar, internal to the underhood fuse block. If it is determined that the ignition main relay is not functioning correctly, the underhood fuse block must be replaced.
- If the ignition 1 voltage is not present on either test point of the ECM IGN fuse, then replace underhood fuse block.
- If the ignition 1 voltage is present on one test point of the ECM IGN fuse, then repair the short to ground in the ignition 1 voltage circuit to the electronic control module (ECM). If the wire circuit tests normal, then replace the ECM.
- If the ignition 1 voltage is present on both test points of the ECM IGN fuse, then inspect and test for loose and corroded terminals at the underhood fuse block electrical connector, and the ECM electrical connectors, which contains the ignition 1 voltage circuit. If the electrical connectors test normal, then repair the ignition 1 voltage circuit, for an open or high resistance. All wire circuit resistance should measure 2 ohms or less. If the wire circuit tests normal, then replace the ECM.
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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.