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DTC P0491 Secondary Air Injection Relay Location and Diagnosis for 2005 Chrysler Sebring 2.4L DOHC

Model: Chrysler Fault Code: P0491 Posted: 2014-03-29 07:27

2005 Chrysler Sebring 2.4L DOHC 4-door sedan with automatic transmission (California model). I'm experiencing a DTC P0496 - Secondary Air Injection System Performance Fault. The code clears when the vehicle is turned off, but I'd like to identify the correct relay location and confirm which component controls the air pump. I believe the secondary air injection relay is located in the under-hood relay center, but I'm unsure of its exact position or how to verify it. Can anyone provide a clear diagram or guidance on identifying the specific relay responsible for powering the air pump? Any help would be greatly appreciated. Note: This issue does not involve engine performance or drivability problems—only the DTC P0491, which indicates an air injection system flow fault during engine operation.

Related fault codes
P0491
Comments (4)
Anonymous 2014-03-29 10:11

The under-hood Power Distribution Center (PDC) cover typically includes a legend identifying each relay. Look for the label 'P0491 - AIR INJECTION SYSTEM PERFORMANCE'. When the engine is running, the PCM monitors air flow through the system. The test begins once sufficient airflow has been accumulated. If the Powertrain Control Module (PCM) detects either excessive or insufficient airflow, the DTC P0491 will be set.

Anonymous 2014-03-29 13:23

Thanks for the input, Kev2—but I checked the under-hood relay cover and it does not list any specific relay designation for the air injection system. The labels are either generic or missing critical component names.

Anonymous 2014-03-29 14:13

After some research, the secondary air injection relay is mounted on a bracket attached to the air pump itself. To locate it: from underneath the vehicle, look up near the intake manifold where the air hose connects to the intake system—this is typically just behind or beside the air pump assembly. The relay is bolted directly to that bracket and can be accessed with basic tools.

Anonymous 2014-03-29 21:15

Thanks, Kev2! Your guidance was incredibly helpful. I've been trying to get this information from my dealership, but they're charging me for retrieving diagnostic codes and then want to replace a small relay—this is unreasonable. As a former shop foreman at Yuba City Honda in California, I used to provide detailed technical support to customers regardless of whether we performed the repair. That customer service approach helped our shop rise from 10th to #1 in just two years. This kind of transparency and helpfulness matters—thank you for sharing your experience!