System Description

WARNING: This page is about a different car, the 2005 Buick LaCrosse and 2005 Buick Allure. However, it is still accessible from the selected car via links, so may be relevant.

The secondary air injection (AIR) system aids in the reduction of hydrocarbon emissions during a cold start. The system forces fresh filtered air into the exhaust stream in order to accelerate the catalyst operation. An electric air pump, the AIR pump, provides filtered air on demand to the AIR control solenoid valve/pressure sensor assembly. The AIR control solenoid valve/pressure sensor assembly controls the flow of air from the AIR pump to the exhaust manifold. The AIR valve relay supplies the current needed to operate the AIR control solenoid valve/pressure sensor assembly. A pressure sensor is used to monitor the air flow from the AIR pump. The powertrain control module (PCM) supplies the internal pressure sensor with a 5-volt reference, an electrical ground, and a signal circuit.

The AIR diagnostic uses 3 phases to test the AIR system:

DTCs P0411 and P2430 run during Phase 1
DTCs P2430 and P2440 run during Phase 2
DTC P2444 runs during Phase 3

In all 3 phases, testing is accomplished by comparing the measured pressure against the expected pressure. The PCM can detect faults in the AIR pump, AIR control solenoid valve/pressure sensor assembly, and the exhaust check valve. The pressure sensor can also detect leaks and restrictions in the secondary AIR system plumbing.

DTC P2430-The AIR system pressure sensor is stuck range diagnostic monitors the amount of change in the sensor signal during phase 1 and phase 2. When the PCM detects AIR pressure sensor signal change is less than expected DTC P2430 sets. DTC P2430 runs during phase 1 and phase 2.