Download Diagnostic Testing for Oxygen Sensors

NTK oxygen catalogue Final
7/4/03 4:22 PM
Page 32
Diagnostic Testing for Oxygen Sensors
OBD ignition on
problem with the
sensor
Course of test
Check Cables
Visual check of cables
Test points
Cable broken or connector damaged?
Cable seal loosened?
Moisture in the connector?
Corroded connector pins?
Wiring in order?
Check sensor
Visual check of sensor
Does the connector show visible damage?
Analysis of sensor
1
2
3
Multimeter
Result
Test
Procedure
Sensor
volatage signal
1. Ignition off, disconnect sensor
connector
2. Attach multimeter to sensor
signal connector (+ black cable)
and earth connector (-battery)
3. Reconnect sensor
4. Run engine continuously for
2 mins at 2000 rpm
5. Carry out test with engine warm
from operation
Voltage oscillates
between 0 and 1 V
Heater
element
1. Disconnect sensor connector
2. Attach multimeter to white
sensor cable
Heater resistance
should be 2 to 14 ohm
at room temperature
1. Heater elements may be
defective. Sensor must be
repalced with new sensor
On-board
current
1. Ignition off, disconnect sensor
connector
2. Attach multimeter to signal
terminal and earth on the
connector to the vehicle
3. Switch on ignition
Voltage is > 10.5 V
1. Check wiring and ground
If not the case
1. Sensor may be defective if
voltage does not change
2. Remove sensor and check for
oil or other deposits
3. Replace with new sensor
In overrun sensor voltage
is continuously O V
Check
1. Check exhaust
for leaks
2. Check electrical
connections
3. Determine oil
consumption
(could be too high due
to defective piston
rings or defective
valve stem seal)