Quiz # 6
Zirconium O2 Sensors
Name ________________________
1. A slightly lean (vacuum leak) A/F mixture will cause a properly functioning 02 sensor to
produce a wave form that is:
a. Fluctuating with average voltage above .45
b. Fluctuating with average voltage below .45
c. Fluctuating equally above and below .45
d. All the above
2. The voltage range from a properly functioning 02 sensor is:
a. 0 to .45
b. .45 to .9
c. .1 to .9
d. .2 to .6
3. Which piece of equipment will monitor an 02 sensor most effectively:
a. DVOM
b. Scan tool
c. DSO
d. All the above
4. A vehicle has a rough idle along with poor engine performance and a low voltage from the 02
sensor, what is most likely cause?
a. Defective post (after the cat) 02 sensor
b. High fuel pressure
c. Open electrical windings in a fuel injector
d. Saturated evaporative canister
5. A vehicle with a fuel system that is operating properly will have an 02 sensor reporting:
a. Minimum voltage = .0mv Maximum voltage = .1mv Average voltage = 500mv
b. Minimum voltage = 150mv Maximum voltage = 850mv Average voltage = 450mv
c. Minimum voltage = .850mv Maximum voltage = 150mv Average voltage = 4.50mv
d. Minimum voltage = 185mv Maximum voltage = 715mv Average voltage = 485mv
6. A lean exhaust will have ________ levels.
a. Low NOx
b. Low oxygen
c. High oxygen
d. A/F ratio between 12.9:1 and 13.8:1
7. Technician A says that adding propane to a vacuum leak will cause the 02-sensor voltage to
decrease towards .1 volt. Technician B says high fuel pressure will cause the 02 sensor to
report a voltage between .1 and .45. Who is correct?
a. A
b. B
c. Both A & B
d. Not A or B
8. The vehicle you are diagnosing has a misfire, you are using a DSO, and how will the
waveform react?
a. Bias lean below .45 volts with increased activity
b. Slow down in frequency, much slower than normal
c. Increase in transitions above .45 volts
d. O2 sensors will not respond to a misfire
9. Using chart below and answer the question about the 02 sensor wave form
1 volt
0 volt
a.
b.
c.
d.
Engine is constantly running lean
Vacuum leak
Engine is constantly running rich
Engine is running normal
10. During open loop computer operation:
a. The computer delivers fuel according to the oxygen content of the exhaust
b. Computer always diverts the air to the atmosphere
c. Computer does not use the 02 sensor input to calculate fuel delivery
d. Computer goes into a “limp home” mode of operation