Grand Prix V6-191 3.1L VIN M SFI (1998)
Oil Level Switch: Description and Operation
DESCRIPTION
The engine oil level sensor is used to detect low engine oil level conditions. The Engine Oil Level (EOL) Switch is a simple float switch that is
grounded when the engine oil level is OK.
OPERATION
The PCM checks the Engine Oil Level switch circuit at start-up. If the engine has been running, the PCM performs a test routine based on engine
coolant temperature to ensure that the engine oil has drained back into the sump before checking the state of the engine oil level switch. If the engine
coolant temperature is between 15°C (59°F) and 140°C (284°F), the PCM compares the engine coolant temperature at the last key OFF to the engine
coolant temperature at the current key on. If the difference between the recorded temperature values is at least 12°C (54°F), the PCM will test the
engine oil level.
The PCM commands the Low Oil Level Lamp ON if the engine oil level sensor indicates that a low oil level condition exists. The PCM determines
whether or not to test for low oil level based on the difference between engine coolant temperature at the last shutdown and engine coolant
temperature at startup. This is to ensure that the oil has drained back into the oil pan before testing.
