LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Volkswagen >> 1985 >> Jetta L4-1781cc 1.8L SOHC >> Repair and Diagnosis >> Powertrain Management >> Computers and Control Systems >> Mixture Control Solenoid >> Technical Service Bulletins >> CIS With OXS System - New Checking/Adjusting Procedures >> Oxygen Sensor, Checking
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Oxygen Sensor, Checking

^ engine oil temperature, min. 80~C (176~F)
^ idle adjustment OK
^ control unit oxygen regulating function OK
^ remote control US 4480/3 not connected
^ oxygen sensor connected



^ connect test equipment for measuring OXS duty cycle

- start engine and let idle for at least 2 min.



- clamp hose (1) of idle speed stabilizer valve together tightly
- remove hose (2) from connecting piece on intake manifold
- hold connecting piece on intake manifold closed and note reading on test equipment
^ duty cycle reading must drop

If NO:
- replace oxygen sensor