WATER-IN-FUEL INDICATOR

DESCRIPTION

A water-in-fuel indicator is standard equipment on all instrument clusters. However, on vehicles not equipped with the optional diesel engine, this indicator is electronically disabled. The water-in-fuel indication appears within the reconfigurable dot matrix Organic Light Emitting Diode (OLED) display unit. The water-in-fuel indicator consists of a textual WATER IN FUELmessage which appears in place of the compass/trip computer information in the dot matrix display.

The dot matrix OLED is soldered onto the cluster electronic circuit board, and is visible through a window with a smoked clear lens located on the lower edge of the tachometer gauge dial face of the cluster overlay. The dark lens over the OLED prevents it from being clearly visible when it is not illuminated. The water-in-fuel indicator textual message appears in the same blue-green color and at the same lighting level as the compass/trip computer information when it is illuminated by the instrument cluster electronic circuit board.

The water-in-fuel indicator is serviced as a unit with the OLED in the instrument cluster.

OPERATION

The water-in-fuel indicator gives an indication to the vehicle operator when there is excessive water detected in the diesel fuel. This indicator is controlled by the instrument cluster logic circuit based upon cluster programming and electronic messages received over the Controller Area Network (CAN) data bus from the Powertrain Control Module (PCM).

The water-in-fuel indicator function of the reconfigurable dot matrix Organic Light Emitting Diode (OLED) display unit is completely controlled by the instrument cluster logic circuit, and that logic will only allow this indicator to operate when the instrument cluster receives a battery current input on the fused ignition switch output (run-start) circuit. Therefore, the OLED water-in-fuel indication will always be OFF when the ignition switch is in any position except ON or START. The instrument cluster will turn ON the water-in-fuel indicator for the following reasons:

• Water-In-Fuel Indicator Lamp-On Message - Each time the cluster receives an electronic water-in-fuel indicator lamp-ON message from the PCM indicating there is excessive water in the diesel fuel system, the water-in-fuel indicator will be illuminated. The indicator remains illuminated until the cluster receives a lamp-OFF message from the PCM, or until the ignition switch is turned to the OFF position, whichever occurs first.

The PCM continually monitors the water-in-fuel sensor to determine whether there is excessive water in the diesel fuel system. The PCM then sends the proper lamp-ON or lamp-OFF message to the ElectroMechanical Instrument Cluster (EMIC).

For proper diagnosis of the water-in-fuel-sensor, the PCM, the EMIC, the CAN data bus, or the electronic communication related to water-in-fuel indicator operation a diagnostic scan tool is required. Refer to the appropriate diagnostic information.