O2 Sensor Test

Test Conditions
Test Results If Not
EGO/HEGO SIGNAL to
Control Unit
-Key off, disconnect EGO sensor
sconnector
-Connect DMM Between EGO SIGNAL
wire dand negative(-) battery terminal
-Engine at normal operating temperature
Approximately 0.55 volts EGO sensor may be faulty
EGO/HEGO SIGNAL to
control unit
-Key off, Disconnect EGO sensor
connector
-Connect DMM between EGO SIGNAL wire
and negative(-)battery terminal
-Engine at normal operating temperature
-Create vacuum leak (disconnect vacuum
hose to intake manifold
Voltage drops and fluctuates EGO sensor may be faulty
PWR -Key off, disconnect HEGO sensor
connector
-Connect DMM between PWR wire and
GROUND at vehicle connector
-Key on
10 Volts or greater Check harness wiring and
grounds
HEGO heater element -Key off, disconnect HEGO sensor
connector
-Connect DMM between KEY POWER wire
and POWER GROUND at sensor connector
Approximately 6 ohms at
room temperature
HEGO heater element faulty
O2 Sensor Test
O2 Sensor Test