Secondary air intake code

[thstone]

There is no sensor (per se) that tells the air pump when to run. Instead, the air pump is commanded on by the ECU depending on coolant temperature (for cold start operation) and engine rpm (for pressure test at idle).

Use your Durametric to manually turn on the SAI pump. That should verify that the pump and all of the electrical connections are good. And if the pump operates manually, then it should operate properly when commanded by the ECU (whether cold start or pressure test).

The most common problems are hose leaks and inop valves.

What CEL code are you getting? That will help us point you in the right direction.

[911monty]

Originally Posted by thstone

There is no sensor (per se) that tells the air pump when to run. Instead, the air pump is commanded on by the ECU depending on coolant temperature (for cold start operation) and engine rpm (for pressure test at idle).

Use your Durametric to manually turn on the SAI pump. That should verify that the pump and all of the electrical connections are good. And if the pump operates manually, then it should operate properly when commanded by the ECU (whether cold start or pressure test).

The most common problems are hose leaks and inop valves.

What CEL code are you getting? That will help us point you in the right direction.

The system check uses the 02 sensors to detect a lean condition when the SAI pump is running. It will then set the MIL code for the bank/banks that are not working.
If a Durametric is available you can monitor the 02 sensors and start the SAI pump to monitor function. Failure points are the air change over valve, the electric switch, vacuum tank and as Jaeger so graphically posted the ports in the heads themselves.