Oil Level Warning Indicator: Description and Operation

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 start-up. This is to ensure that the oil has drained back into the oil pan before testing.

The engine oil level switch is a simple float switch that is grounded when the engine oil level is OK. When the ignition is first turned ON, the PCM commands the low oil level lamp ON for a brief period of time to test the bulb, approximately 3 seconds. The PCM also 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 drained back into the sump before checking the state of the engine oil level switch. if the engine coolant temperature is between 15°C-130°C (59°F-266°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.