Air Injection: Testing and Inspection

NOTE: The "ELECTRIC AIR PUMP OUTPUT CHECK" is described for the TECH-1 diagnostic scan tool or equivalent. If a scan tool with this output function is not available or if system is not operating correctly, perform inspection as described below.

ELECTRIC AIR PUMP OUTPUT CHECK
With engine at normal operating temperature in neutral at idle, connect a "Scan" tool. Select "Miscellaneous test" then "Output test". Select "AIR system" in "Output test" directory. Exit to "Data list" and select oxygen sensor voltages for both left and right oxygen sensors. Enable the "Output test" for the AIR system.

The "Output test" will energize the electric air pump and the ESV solenoid for only 5 seconds. When the "Output test" is enabled, the oxygen sensor voltages for both sensors should remain under .4 volts because air is being directed to the exhaust ports.

If the oxygen sensor voltages remain low during the "Output test" the electric air pump and integral stop valve are operating satisfactorily.

INSPECTION

ELECTRIC AIR PUMP
1. For a seized electric air pump
2. Hoses, tubes and all connections for leaks and proper routing
3. AIR pump for proper mounting


HOSES AND PIPES
1. Hose or pipe for deterioration or holes
2. All hoses or pipe connections, and clamp tightness
3. Hose or pipe routing
4. If a leak is suspected on the pressure side of the system or if a hose or pipe has been disconnected on the pressure side, the connections should be checked for with a soapy water solution. With the electric air pump running, bubbles will form if a leak exists.

Check Valve
1. Check valves should be inspected whenever the hose is disconnected or when failure is suspected.

2. Blow through the check valve toward the cylinder head. Air should pass through the valve. Then, with supply hoses disconnected from check valves, start engine and listen for exhaust noise from check valves. There should be no exhaust noise and no exhaust coming from the check valves. If there is, replace check valve(s).