The oil change reminder indicator informs the driver that the engine requires an engine oil change due to excessive build up of fuel within the engine oil. This is due to the DPF regeneration process where additional fuel quantities are added to increase exhaust gas temperatures. As a result small quantities of unburnt fuel remain in the combustion chamber and bypass the piston rings into the engine oil.
The amount of excessive fuel is calculated by the PCM. The PCM monitors the engine operating conditions and the values from the exhaust gas temperature sensor during the DPF regeneration process and calculates the amount of fuel in the oil. If the fuel content exceeds the permitted level, the PCM will illuminate the oil change reminder indicator in the instrument cluster.
After the engine oil has been changed, a service indicator reset procedure must be carried out.
For additional information, refer to: Oil Change Indicator Reset (413-09 Warning Devices, General Procedures).
