What Does P1423 Mean?
The PCM has detected insufficient airflow from the Secondary Air Injection system on Bank 1. The system is operating but not delivering adequate air volume to reduce cold-start emissions.
Common Causes
30%
Restricted or clogged SAI air filter or intake screen
25%
Weak or failing SAI air pump not generating adequate pressure
20%
Leaking SAI check valve allowing exhaust backflow
15%
Partially blocked SAI passages or carbon buildup in injection ports
10%
Stuck or partially closed SAI diverter valve
Diagnostic Steps
1
Step 1: Start engine cold and command SAI system on with scan tool - listen for pump operation and check for airflow at pump outlet
2
Step 2: Inspect and clean or replace SAI air filter and intake screen for restrictions
3
Step 3: Disconnect air supply hose at check valve and verify strong airflow from pump during activation
4
Step 4: Remove and inspect check valve for proper operation - should allow air in one direction only and seal completely
5
Step 5: Check SAI system hoses and connections for leaks using smoke test; inspect injection tubes for carbon blockage
Estimated Repair Cost
$200 - $900
Parts + labor, varies by vehicle and location
The PCM has detected insufficient airflow from the Secondary Air Injection system on Bank 1. The system is operating but not delivering adequate air volume to reduce cold-start emissions.
The most common cause of P1423 (Sec.Air Inj.Sys.,Bank1 Flow too Low) is: Restricted or clogged SAI air filter or intake screen
Typical repair costs for P1423 range from $200 to $900, depending on the vehicle, location, and whether you do it yourself or go to a shop.
No safety concerns for vehicle operation. This impacts emissions performance only, resulting in increased cold-start emissions and potential emissions test failure.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1423 to identify the root cause.
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Quick Info
Category
Powertrain
System
Emissions Control - Secondary Air Injection
Difficulty
Type
Manufacturer
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