CHECKING FUNCTION OF OXYGEN SENSOR
Connect digital tester.
Adjust idle speed 13 00 054.
Unscrew cap nut (1).
Attach exhaust probe 13 0 070 on exhaust line.
Connect CO tester.


13 00 054

Pull off hose (2) from collector to carbon canister
and don´t plug opening.
Measure and note CO level.
CO level should be between 0.2 and 0.8 % by
volume.
CO Level Too Low:
1.) Leak in intake system after air flow sensor.
Check intake pipes, intake necks, hoses and
connections for leaks.
2.) Leak in crankcase.
Check valve cover seal, oil pan, oil dipstick
and vent line for leaks.

Tighten CO adjusting screw with Special Tool
13 1 060.
This should not change the CO level.
If CO level rises, oxygen sensor is defective.

Disconnect plug receptacle (3) for oxygen
sensor.
Readjust the high CO level to the value measured
earlier with the oxygen sensor.
Connect plug receptacle (3) again.
Important: If car had been driven on gasoline
containing lead, replace oxygen sensor and catalytic
converter.

Vehicles after change point in 1982
CHECKING FUNCTION OF
OXYGEN SENSOR
Unscrew plug (1).
Screw in Special Tool 13 0 100 and attach the Special Tool 13 0 090.
Connect the BMW service tester.

Measure the CO level.
Specifications: 0.2 to 1.2 % by volume.
Refer to 13 00 054 for other information.


13 00 054

Pull off vacuum hose (1) on the pressure regulator and plug.
The CO level will rise briefly and is immediately regulated back to the original value
= the oxygen sensor is working.
If Not:
Check the power supply to the oxygen sensor from the relay according to the wiring diagram.
See Group 13 for additional information.