Diagnostic Aids
WARNING: This page is about a different car, the 2006 Buick LaCrosse and 2006 Buick Allure. However, it is still accessible from the selected car via links, so may be relevant.
Inspect for any of the following conditions:
- An AIR pump that fails to turn OFF may set DTC P2431.
- The AIR pump can be damaged if it fails to turn OFF. Inspect and correct the cause of an inoperable pump before replacing pump.
- The resistance of the AIR pump relay coil (across terminal 85 and terminal 86) is 50-70 ohms at 20°C (68°F). In the normal unenergized state, the resistance of the open relay contacts (across terminal 30 and terminal 87) is infinite.
- The AIR pump relays electrical contacts may be pitted and sticking. Replace the relay if tapping gently on the relay or wiggling the relay causes a change in the relays operation.
- The performance of the AIR pump relay may be affected by temperature. Check the relay after sitting outside overnight and after running the engine 30 minutes.
- An intermittent malfunction may be caused by a fault in an AIR system electrical circuit. Inspect the wiring harness and components for an intermittent condition. Refer to Testing for Intermittent Conditions and Poor Connections .