| 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