The PCM controlled lamps are intended to alert the driver to an operating condition which may require immediate attention.
The PCM commands the Low Oil Level Lamp ON if the engine oil level switch 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.
Engine Oil Level Switch
The engine oil level switch is a float switch that is grounded when the engine oil level is OK. The PCM checks engine oil level at startup. Before checking the state of the engine oil level switch, the PCM performs a test routine based on time and engine coolant temperature to ensure that the engine oil has drained back into the sump. To test for low oil level at startup, the following conditions must be present:
| • | Startup engine coolant temperature must be greater than 15° C (59° F). |
| • | Startup engine coolant temperature must be at least 12° C (22° F) cooler than the engine coolant temperature was at the last key OFF. |
The low engine oil level lamp will be illuminated for about a minute when the PCM checks for low oil level and the engine oil level switch indicates that a low oil level condition exists (engine oil level switch circuit not grounded). When the ignition is first turned ON, the PCM commands the low engine oil level lamp ON for a brief period of time to test the bulb.
