This SYSTEM is made available for the dissemination of valuable information between members of the automotive industry who service automobiles manufactured by Daimler-Benz ("Mercedes"). However, manufacturer guidelines should always be followed. This SYSTEM provides a means for more easily discussing the beneficial use of such instructions. You should always consult your official resources and manuals before that which you find on the Internet, and you should always confirm all procedures with the appropriate manufacturer or specialist before proceeding.
Category:	ENGINE
MODEL:	140
ENGINE:	119
YEAR:
SYMPTOMS:	The vehicle check engine light on Code 017 displayed Air injection Malfunction
TEST:	Perform standard visual test of connector to air pump and vacuum hoses to switchover valves and diverter valve.
TEST:	Operate engine till 80 degree Celsius is reached Apply vacuum to diverter valve Activate Air Pump for 10 seconds Monitor oxygen sensor and verify oxygen sensor voltage drop below .040 volts. (This verifies air injection passages are clear and pump is pumping sufficient air)
POSSIBLE CAUSE:	A failure of the air pump switchover valve vacuum source plastic tubing which lays inside a plastic shield routed under the air pump. The tubing starts at the manifold and end at the switchover valve. The heat generated and the torque of the engine contributes to the breakage. The tubes are not visible so detection is difficult. Replacement requires tubing and a new sleeve for protection. OEM parts should be used.
NOTES:	The vacuum switchover valves are located behind the right front headlight assembly