DeVille, Eldorado, Seville 1999-2005

Secondary Air Injection System

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Operation



Secondary Air Injection (AIR) Pump

The secondary air injection (AIR) system helps reduce exhaust emissions. The system forces fresh filtered air into the exhaust stream in order to accelerate catalyst operation.

The system includes the following:



AIR pump--The AIR pump supplies filtered air through the secondary air injection system into the exhaust stream. The control module provides ground for the pump relay. Battery voltage is then applied to the pump. The filter is the only serviceable part of the pump.
 
AIR vacuum control solenoid--The AIR vacuum control solenoid controls the AIR shut-off valves. When the secondary air injection system is enabled, the control module provides a ground to the solenoid. Enabling the solenoid, allows engine vacuum to be applied to the AIR shut-off valves.
 
AIR shut-off valves--The AIR shut-off valves are vacuum operated. When the secondary air injection system is enabled, vacuum is applied to the valves. The vacuum opens the valves and allows air from the AIR pump to flow to the check valves.
 
Check valve--The check valve prevents back flow of exhaust gases into the secondary air injection system. An AIR pump that had become inoperative and had shown indications of having exhaust gases in the outlet port would indicate check valve failure.
 
Plumbing--The plumbing carries the air from the pump to the exhaust stream. The plumbing includes the hoses, pipes and clamps. The plumbing can be tested for leaks using a soapy water solution. With the AIR pump running, bubbles will form if a leak exists.
 

Results Of Incorrect Operation

If no air (oxygen) flow enters the exhaust stream, the start up emission levels will rise. The control module can detect a system flow problem using the pre-catalyst heated oxygen sensor (HO2S) and short term FT. If a system flow problem is present the HO2S voltage will not indicate an expected lean condition, short term FT will not increase and a diagnostic trouble code (DTC) will set.

If incorrect voltage is present on the vacuum control solenoid or the pump relay control circuits the device will not operate. This will be detected by the control module and a DTC will set.

The following DTCs can set if a secondary air injection fault is detected:



DTC P0410-- A system flow problem has been detected.
 
DTC P0412-- A vacuum control solenoid control circuit problem has been detected.
 
DTC P0418-- A pump relay control circuit problem has been detected.
 
DTC P1415-- A system flow problem has been detected relating to cylinder bank 1.
 
DTC P1416-- A system flow problem has been detected relating to cylinder bank 2.
 

Removal & Installation



Air Pump
  1. Raise the vehicle.
  2.  
  3. Remove the retaining screws from the front portion of the left front wheel well/splash shield.
  4.  
  5. Lower the splash shield far enough to gain access to the secondary air injection (AIR) pump (2) assembly.
  6.  
  7. Loosen and lower the AIR outlet hose pinch clamp.
  8.  
  9. Remove the AIR inlet hose from the AIR pump (2).
  10.  
  11. Disconnect the AIR pump electrical connector.
  12.  
  13. Remove the upper AIR pump to cradle bolt.
  14.  
  15. Lift up and pull out to remove the AIR pump (2) from the cradle bracket.

    Click image to see an enlarged view

    Fig. Indicating components for removal of the AIR Pump

  16.  

To install:

  1. Install the lower AIR pump bolts/nuts into the cradle bracket and push down.
  2.  
  3. Install the upper AIR pump to cradle bolt. Tighten the upper and lower AIR pump to cradle bolts to 9 Nm (80 inch lbs.).
  4.  
  5. Reconnect the AIR pump electrical connector.
  6.  
  7. Install the AIR outlet hose and pinch clamp to the AIR pump (2).
  8.  
  9. Install the AIR inlet hose to the AIR pump (2).
  10.  
  11. Lower the vehicle.
  12.  

Air Solenoid Or Pump Relay
  1. Remove the fuel injector sight shield.
  2.  
  3. Disconnect the AIR vacuum control valve electrical connector.
  4.  
  5. Disconnect the vacuum lines.
  6.  
  7. Remove the nut securing the AIR vacuum control valve to the bank 1 AIR shut-off valve bracket.
  8.  
  9. Remove the AIR vacuum control valve.
  10.  

To install:

  1. Install the AIR vacuum control valve to the bank 1 AIR shut-off valve bracket. Tighten the nut to 9 Nm (80 inch lbs.).
  2.  
  3. Reconnect the vacuum lines.
  4.  
  5. Reconnect the AIR vacuum control valve electrical connector.
  6.  
  7. Install the fuel injector sight shield.
  8.  

 
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