Operation

OPERATION

The low oil level indicator gives an indication to the vehicle operator when the engine oil level is too low. This indicator is controlled by a transistor on the instrument cluster circuit board based upon cluster programming and electronic messages received by the cluster over the Controller Area Network (CAN) data bus from the Engine Control Module (ECM) (also known as the Powertrain Control Module/PCM).

The low oil level indicator Light Emitting Diode (LED) or icon and textual message display are completely controlled by the instrument cluster logic circuit, and that logic will only allow this indicator to operate or icon and textual message to be displayed when the instrument cluster detects that the ignition switch is in the ON position. Therefore, the LED or the icon and textual message will always be OFF when the ignition switch is in any position except ON. The LED only illuminates or the icon and textual message are only displayed when it is activated by the instrument cluster logic. The instrument cluster will turn ON the low oil level indicator for the following reasons:

- Bulb Test - On vehicles not equipped with the optional steering wheel buttons, each time the ignition switch is turned to the ON position the low oil level indicator is illuminated by the cluster briefly as a bulb test.
- Low Oil Level Indicator Lamp-On Message - On vehicles not equipped with the optional steering wheel buttons, each time the cluster receives an electronic low oil level indicator lamp-ON message from the ECM, the low oil level indicator will be illuminated. Once the engine has been started, the indicator will flash each time the cluster receives a message from the ECM indicating that the engine oil level is at or near the Minimum mark on the dipstick. If the oil level drops any further, the indicator will illuminate solid, an audible alert will sound and a 2.0 l (2.0 Liters) textual message will be displayed. If the oil level exceeds the Maximum mark on the dipstick, the indicator will illuminate solid, an audible alert will sound and a HI textual message will be displayed. The indicator remains illuminated until the engine oil level is corrected, or until the ignition switch is turned to the OFF position, whichever occurs first.
- Low Oil Level Indicator Lamp-On Message - On vehicles equipped with the optional steering wheel buttons, each time the cluster receives an electronic low oil level indicator lamp-ON message from the ECM, the low oil level icon and a textual message will appear within the cluster multi-function display. The available textual messages include: Engine oil level - Stop, turn engine off, Engine oil level - Check oil level, Engine oil - Add 1.0 liter (quart), Engine oil level - Reduce oil level, Oil sensor - Visit workshop or Engine oil level - Not when eng. running. The icon and textual message remain displayed until the cluster receives a lamp-OFF message from the ECM, or until the ignition switch is turned to the OFF position, whichever occurs first.

The ECM continually monitors the engine oil level sensor to determine the engine oil level. The ECM then sends the proper lamp-ON or lamp-OFF messages to the ElectroMechanical Instrument Cluster (EMIC) (also known as the Cab Compartment Node/CCN or KOMBI). If the ECM sends a lamp-ON message after the bulb test, it indicates that the ECM has detected that the engine oil level is too low or too high, which could result in engine damage. The ECM will store a Diagnostic Trouble Code (DTC) for any malfunction it detects.

On vehicles equipped with the optional diesel engine, the engine oil level can be displayed in the cluster multi-function display as monitored by the ECM through the engine oil level sensor while the vehicle is standing level with the engine at normal operating temperature and switched OFF for at least five minutes. See the owner's information packet in the vehicle glove box for more information on this feature.

For proper diagnosis of the engine oil level sensor, the ECM, the EMIC, the CAN data bus or the electronic communication related to low oil level indicator operation, a diagnostic scan tool is required. Refer to the appropriate diagnostic information.