Spectrum 3.0L GM - Page 211

211
DTC 522739 Oxygen Sensor Short/Open
Step Action Value(s) Yes No
1
Did you perform the On-board diagnostics (OBD)
system check?
Go to Step
(2)
Go to On-
Board
Diagnostics
System
Check/
Malfunction
indicator
lamp.
2
 Key OFF, disconnect C018
 Key ON, measure voltage from C018 pin D
to ground.
Is battery voltage present?
NOTE: Voltage is supplied from the Component
Power Relay circuit and will only be present for
1 to 2 seconds when the key is first turned on.
Go to Step
(3)
Repair open
in Component
Power Relay
circuit. Go to
Step (8)
3
 Measure resistance across the O2 sensor
heater circuit, pins C and D.
Is the resistance 9.6, ± 1.5 @ 21˚C?
9.6, ±
1.5 @
21˚C?
Go to Step
(4)
Replace the
O2 Sensor.
Go to Step
(8)
4
 Measure the resistance from the O2 sensor
heater circuit pins C and D to ground
 Is the resistance greater than 30M?
NOTE: Do not probe wires without proper ser-
vice tool. Permanent harness damage may
result.
>30M
Go to Step
(5)
Replace the
O2 Sensor.
Go to Step
(8)
5
 Key OFF, disconnect ECU-C
 Measure resistance from C018 pin C to
ECU-C pin L2
Is the resistance less than 5?
<5M
Go to Step
(6)
Repair the
open in the
circuit. Go to
Step (8)
6
 Measure the resistance from C018 pin C to
ground.
Is the resistance greater than 30M?
>30M
Go to Step
(7)
Repair the
short to
ground in the
harness. Go
to Step (8)
7
 Key ON, engine running, monitor the system
for faults
 Flex the connectors at the ECU while watch-
ing for faults
Was a fault indicated by wiggling the wires?
Repair or re-
place the
ECU harness.
Go to Step
(8)
Replace the
ECU. Go to
Step (8)